Fossil

/*
** Renders diffs for ajax routes. pOrig is the "original" (v1) content
** and pContent is the locally-edited (v2) content. diffFlags is any
** set of flags suitable for passing to text_diff().
*/
void ajax_render_diff(Blob * pOrig, Blob *pContent, u64 diffFlags){
  Blob out = empty_blob;
  DiffConfig DCfg;

  diff_config_init(&DCfg, diffFlags);
  text_diff(pOrig, pContent, &out, &DCfg);
  if(blob_size(&out)==0){
    /* nothing to do */
  }else if(DIFF_SIDEBYSIDE & diffFlags){
    CX("%b",&out);
  }else{
    CX("<pre class='udiff'>%b</pre>",&out);
  }

    blob_append(&prompt,
      "#\n"
      "# All merged-in branches will be closed due to the --integrate flag\n"
      "#\n", -1
    );
  }
  if( p->verboseFlag ){
    DiffConfig DCfg;
    blob_appendf(&prompt,
        "#\n%.78c\n"
        "# The following diff is excluded from the commit message:\n#\n",
        '#'
    );
    diff_config_init(&DCfg, DIFF_VERBOSE);
    if( g.aCommitFile ){
      FileDirList *diffFiles;
      int i;
      diffFiles = fossil_malloc_zero((g.argc-1) * sizeof(*diffFiles));
      for( i=0; g.aCommitFile[i]!=0; ++i ){
        diffFiles[i].zName  = db_text(0,
         "SELECT pathname FROM vfile WHERE id=%d", g.aCommitFile[i]);
        if( fossil_strcmp(diffFiles[i].zName, "." )==0 ){
          diffFiles[0].zName[0] = '.';
          diffFiles[0].zName[1] = 0;
          break;
        }
        diffFiles[i].nName = strlen(diffFiles[i].zName);
        diffFiles[i].nUsed = 0;
      }
      diff_against_disk(0, 0, diff_get_binary_glob(),
                        db_get_boolean("diff-binary", 1),
                        &DCfg, diffFiles, &prompt);
      for( i=0; diffFiles[i].zName; ++i ){
        fossil_free(diffFiles[i].zName);
      }
      fossil_free(diffFiles);
    }else{
      diff_against_disk(0, 0, diff_get_binary_glob(),
                        db_get_boolean("diff-binary", 1),
                        &DCfg, 0, &prompt);
    }
  }
  prompt_for_user_comment(pComment, &prompt);
  blob_reset(&prompt);
}

/*

    "whitespace changes only\n"

/*
** Maximum length of a line in a text file, in bytes.  (2**15 = 32768 bytes)
*/
#define LENGTH_MASK_SZ  15
#define LENGTH_MASK     ((1<<LENGTH_MASK_SZ)-1)

/*
** An instance of this object describes the formatting and processing
** details desired of a "diff" operation.
**
** Conceptually, this object is as an encoding of the command-line options
** for the "fossil diff" command.  That is not a precise description, though,
** because not all diff operations are started from the command-line.  But
** the idea is sound.
**
** Information encoded by this object includes but is not limited to:
**
**    *   The desired output format (unified vs. side-by-side, 
**        TCL, JSON, HTML vs. plain-text).
**
**    *   Number of lines of context surrounding each difference block
**
**    *   Width of output columns for text side-by-side diffop          
*/
struct DiffConfig {
  u64 diffFlags;           /* Diff flags */
  u32 nFile;               /* Number of files diffed so far */
  const char *zDiffCmd;    /* External diff command to use instead of builtin */
  const char *zBinGlob;    /* GLOB pattern for binary files */
  ReCompiled *pRe;         /* Show only changes matching this pattern */
};

#endif /* INTERFACE */

/*
** Initialize memory for a DiffConfig based on just a diffFlags integer.
*/
DiffConfig *diff_config_init(DiffConfig *pCfg, u64 diffFlags){
  memset(pCfg, 0, sizeof(*pCfg));
  pCfg->diffFlags = diffFlags;
  return pCfg;
}

/*
** Information about each line of a file being diffed.
**
** The lower LENGTH_MASK_SZ bits of the hash (DLine.h) are the length
** of the line.  If any line is longer than LENGTH_MASK characters,
** the file is considered binary.

/*
** Output a patch-style text diff.
*/
static void contextDiff(
  DContext *p,      /* The difference */
  Blob *pOut,       /* Output a context diff to here */
  DiffConfig *pCfg  /* Configuration options */
){
  DLine *A;     /* Left side of the diff */
  DLine *B;     /* Right side of the diff */
  int a = 0;    /* Index of next line in A[] */
  int b = 0;    /* Index of next line in B[] */
  int *R;       /* Array of COPY/DELETE/INSERT triples */
  int r;        /* Index into R[] */
  int nr;       /* Number of COPY/DELETE/INSERT triples to process */
  int mxr;      /* Maximum value for r */
  int na, nb;   /* Number of lines shown from A and B */
  int i, j;     /* Loop counters */
  int m;        /* Number of lines to output */
  int skip;     /* Number of lines to skip */
  static int nChunk = 0;  /* Number of diff chunks seen so far */
  int nContext;    /* Number of lines of context */
  int showLn;      /* Show line numbers */
  int showDivider = 0;  /* True to show the divider between diff blocks */

  nContext = diff_context_lines(pCfg);
  showLn = (pCfg->diffFlags & DIFF_LINENO)!=0;
  A = p->aFrom;
  B = p->aTo;
  R = p->aEdit;
  mxr = p->nEdit;
  while( mxr>2 && R[mxr-1]==0 && R[mxr-2]==0 ){ mxr -= 3; }
  for(r=0; r<mxr; r += 3*nr){
    /* Figure out how many triples to show in a single block */

                         pY->z + chng.a[i].iStart2, chng.a[i].iLen2);
  }
  blob_append_char(p->pOut, ',');
  blob_append_json_literal(p->pOut, pX->z + x, pX->n - x);
  blob_append(p->pOut, "],\n",3);
}
static void dfjsonEnd(DiffBuilder *p){
  blob_append(p->pOut, "0]}", 3);
  fossil_free(p);
}
static DiffBuilder *dfjsonNew(Blob *pOut){
  DiffBuilder *p = fossil_malloc(sizeof(*p));
  p->xSkip = dfjsonSkip;
  p->xCommon = dfjsonCommon;
  p->xInsert = dfjsonInsert;

  blob_appendf(p->pOut, " | %6u ", p->lnRight);
  sbs_append_chars(p->pOut, 0, p->width, pY);
  blob_append_char(p->pOut, '\n');
}
static void dfsbsEnd(DiffBuilder *p){
  fossil_free(p);
}
static DiffBuilder *dfsbsNew(Blob *pOut, DiffConfig *pCfg){
  DiffBuilder *p = fossil_malloc(sizeof(*p));
  p->xSkip = dfsbsSkip;
  p->xCommon = dfsbsCommon;
  p->xInsert = dfsbsInsert;
  p->xDelete = dfsbsDelete;
  p->xReplace = dfsbsEdit;
  p->xEdit = dfsbsEdit;
  p->xEnd = dfsbsEnd;
  p->lnLeft = p->lnRight = 0;
  p->width = diff_width(pCfg);
  p->pOut = pOut;
  return p;
}
/****************************************************************************/
/*
** Return the number between 0 and 100 that is smaller the closer pA and
** pB match.  Return 0 for a perfect match.  Return 100 if pA and pB are

** each other.  Insertion and deletion costs are 50.  Match costs
** are between 0 and 100 where 0 is a perfect match 100 is a complete
** mismatch.
*/
static unsigned char *diffBlockAlignment(
  const DLine *aLeft, int nLeft,     /* Text on the left */
  const DLine *aRight, int nRight,   /* Text on the right */
  DiffConfig *pCfg,                  /* Configuration options */
  int *pNResult                      /* OUTPUT: Bytes of result */
){
  int i, j, k;                 /* Loop counters */
  int *a;                      /* One row of the Wagner matrix */
  int *pToFree;                /* Space that needs to be freed */
  unsigned char *aM;           /* Wagner result matrix */
  int nMatch, iMatch;          /* Number of matching lines and match score */

  }

  /* For large alignments, use a divide and conquer algorithm that is
  ** O(NlogN).  The result is not as precise, but this whole thing is an
  ** approximation anyhow, and the faster response time is an acceptable
  ** trade-off for reduced precision.
  */
  if( nLeft*nRight>DIFF_ALIGN_MX && (pCfg->diffFlags & DIFF_SLOW_SBS)==0 ){
    const DLine *aSmall;   /* The smaller of aLeft and aRight */
    const DLine *aBig;     /* The larger of aLeft and aRight */
    int nSmall, nBig;      /* Size of aSmall and aBig.  nSmall<=nBig */
    int iDivSmall, iDivBig;  /* Divider point for aSmall and aBig */
    int iDivLeft, iDivRight; /* Divider point for aLeft and aRight */
    unsigned char *a1, *a2;  /* Results of the alignments on two halves */
    int n1, n2;              /* Number of entries in a1 and a2 */

    if( aSmall==aRight ){
      iDivRight = iDivSmall;
      iDivLeft = iDivBig;
    }else{
      iDivRight = iDivBig;
      iDivLeft = iDivSmall;
    }
    a1 = diffBlockAlignment(aLeft,iDivLeft,aRight,iDivRight,pCfg,&n1);
    a2 = diffBlockAlignment(aLeft+iDivLeft, nLeft-iDivLeft,
                            aRight+iDivRight, nRight-iDivRight,
                            pCfg, &n2);
    a1 = fossil_realloc(a1, n1+n2 );
    memcpy(a1+n1,a2,n2);
    fossil_free(a2);
    *pNResult = n1+n2;
    return a1;
  }

}

/*
** Format a diff using a DiffBuilder object
*/
static void formatDiff(
  DContext *p,           /* The computed diff */

  DiffConfig *pCfg,      /* Configuration options */
  DiffBuilder *pBuilder  /* The formatter object */
){
  const DLine *A;        /* Left side of the diff */
  const DLine *B;        /* Right side of the diff */
  unsigned int a = 0;    /* Index of next line in A[] */
  unsigned int b = 0;    /* Index of next line in B[] */
  const int *R;          /* Array of COPY/DELETE/INSERT triples */
  unsigned int r;        /* Index into R[] */
  unsigned int nr;       /* Number of COPY/DELETE/INSERT triples to process */
  unsigned int mxr;      /* Maximum value for r */
  unsigned int na, nb;   /* Number of lines shown from A and B */
  unsigned int i, j;     /* Loop counters */
  unsigned int m, ma, mb;/* Number of lines to output */
  signed int skip = 0;   /* Number of lines to skip */
  unsigned int nContext; /* Lines of context above and below each change */

  nContext = diff_context_lines(pCfg);
  A = p->aFrom;
  B = p->aTo;
  R = p->aEdit;
  mxr = p->nEdit;
  while( mxr>2 && R[mxr-1]==0 && R[mxr-2]==0 ){ mxr -= 3; }

  for(r=0; r<mxr; r += 3*nr){
    /* Figure out how many triples to show in a single block */
    for(nr=1; R[r+nr*3]>0 && R[r+nr*3]<nContext*2; nr++){}

    /* If there is a regex, skip this block (generate no diff output)
    ** if the regex matches or does not match both insert and delete.
    ** Only display the block if one side matches but the other side does
    ** not.
    */
    if( pCfg->pRe ){
      int hideBlock = 1;
      int xa = a, xb = b;
      for(i=0; hideBlock && i<nr; i++){
        int c1, c2;
        xa += R[r+i*3];
        xb += R[r+i*3];
        c1 = re_dline_match(pCfg->pRe, &A[xa], R[r+i*3+1]);
        c2 = re_dline_match(pCfg->pRe, &B[xb], R[r+i*3+2]);
        hideBlock = c1==c2;
        xa += R[r+i*3+1];
        xb += R[r+i*3+2];
      }
      if( hideBlock ){
        a = xa;
        b = xb;

        i++;
        m = R[r+i*3];
        ma += R[r+i*3+1] + m;
        mb += R[r+i*3+2] + m;
      }

      /* Try to find an alignment for the lines within this one block */
      alignment = diffBlockAlignment(&A[a], ma, &B[b], mb, pCfg, &nAlign);

      for(j=0; ma+mb>0; j++){
        assert( j<nAlign );
        switch( alignment[j] ){
          case 1: {
            /* Delete one line from the left */
            pBuilder->xDelete(pBuilder, &A[a]);

  }
}

/*
** Extract the number of lines of context from diffFlags.  Supply an
** appropriate default if no context width is specified.
*/
int diff_context_lines(DiffConfig *pCfg){
  int n = pCfg->diffFlags & DIFF_CONTEXT_MASK;
  if( n==0 && (pCfg->diffFlags & DIFF_CONTEXT_EX)==0 ) n = 5;
  return n;
}

/*
** Extract the width of columns for side-by-side diff.  Supply an
** appropriate default if no width is given.
**
** Calculate the default automatically, based on terminal's current width:
**   term-width = 2*diff-col + diff-marker + 1
**   diff-col = lineno + lmargin + text-width + rmargin
**
**   text-width = (term-width - diff-marker - 1)/2 - lineno - lmargin - rmargin
*/
int diff_width(DiffConfig *pCfg){
  int w = (pCfg->diffFlags & DIFF_WIDTH_MASK)/(DIFF_CONTEXT_MASK+1);
  if( w==0 ){
    static struct {
      unsigned int lineno, lmargin, text, rmargin, marker;
    } sbsW = { 5, 2, 0, 0, 3 };
    const unsigned int wMin = 24, wMax = 132;
    unsigned int tw = terminal_get_width(80);
    unsigned int twMin =

** file is encountered, 0 is returned and pOut is written with
** text "cannot compute difference between binary files".
*/
int *text_diff(
  Blob *pA_Blob,   /* FROM file */
  Blob *pB_Blob,   /* TO file */
  Blob *pOut,      /* Write diff here if not NULL */
  DiffConfig *pCfg /* Configuration options */

){
  int ignoreWs; /* Ignore whitespace */
  DContext c;

  if( pCfg->diffFlags & DIFF_INVERT ){
    Blob *pTemp = pA_Blob;
    pA_Blob = pB_Blob;
    pB_Blob = pTemp;
  }
  ignoreWs = (pCfg->diffFlags & DIFF_IGNORE_ALLWS)!=0;
  blob_to_utf8_no_bom(pA_Blob, 0);
  blob_to_utf8_no_bom(pB_Blob, 0);

  /* Prepare the input files */
  memset(&c, 0, sizeof(c));
  if( (pCfg->diffFlags & DIFF_IGNORE_ALLWS)==DIFF_IGNORE_ALLWS ){
    c.xDiffer = compare_dline_ignore_allws;
  }else{
    c.xDiffer = compare_dline;
  }
  c.aFrom = break_into_lines(blob_str(pA_Blob), blob_size(pA_Blob),
                             &c.nFrom, pCfg->diffFlags);
  c.aTo = break_into_lines(blob_str(pB_Blob), blob_size(pB_Blob),
                           &c.nTo, pCfg->diffFlags);
  if( c.aFrom==0 || c.aTo==0 ){
    fossil_free(c.aFrom);
    fossil_free(c.aTo);
    if( pOut ){
      diff_errmsg(pOut, DIFF_CANNOT_COMPUTE_BINARY, pCfg->diffFlags);
    }
    return 0;
  }

  /* Compute the difference */
  diff_all(&c);
  if( ignoreWs && c.nEdit==6 && c.aEdit[1]==0 && c.aEdit[2]==0 ){
    fossil_free(c.aFrom);
    fossil_free(c.aTo);
    fossil_free(c.aEdit);
    if( pOut ) diff_errmsg(pOut, DIFF_WHITESPACE_ONLY, pCfg->diffFlags);
    return 0;
  }
  if( (pCfg->diffFlags & DIFF_NOTTOOBIG)!=0 ){
    int i, m, n;
    int *a = c.aEdit;
    int mx = c.nEdit;
    for(i=m=n=0; i<mx; i+=3){ m += a[i]; n += a[i+1]+a[i+2]; }
    if( n>10000 ){
      fossil_free(c.aFrom);
      fossil_free(c.aTo);
      fossil_free(c.aEdit);
      if( pOut ) diff_errmsg(pOut, DIFF_TOO_MANY_CHANGES, pCfg->diffFlags);
      return 0;
    }
  }
  if( (pCfg->diffFlags & DIFF_NOOPT)==0 ){
    diff_optimize(&c);
  }

  if( pOut ){
    if( pCfg->diffFlags & DIFF_NUMSTAT ){
      int nDel = 0, nIns = 0, i;
      for(i=0; c.aEdit[i] || c.aEdit[i+1] || c.aEdit[i+2]; i+=3){
        nDel += c.aEdit[i+1];
        nIns += c.aEdit[i+2];
      }
      g.diffCnt[1] += nIns;
      g.diffCnt[2] += nDel;
      if( nIns+nDel ){
        g.diffCnt[0]++;
        blob_appendf(pOut, "%10d %10d", nIns, nDel);
      }
    }else if( pCfg->diffFlags & DIFF_RAW ){
      const int *R = c.aEdit;
      unsigned int r;
      for(r=0; R[r] || R[r+1] || R[r+2]; r += 3){
        blob_appendf(pOut, " copy %6d  delete %6d  insert %6d\n",
                     R[r], R[r+1], R[r+2]);
      }
    }else if( pCfg->diffFlags & DIFF_JSON ){
      DiffBuilder *pBuilder = dfjsonNew(pOut);
      formatDiff(&c, pCfg, pBuilder);
      blob_append_char(pOut, '\n');
    }else if( pCfg->diffFlags & DIFF_TCL ){
      DiffBuilder *pBuilder = dftclNew(pOut);
      formatDiff(&c, pCfg, pBuilder);
    }else if( pCfg->diffFlags & DIFF_SIDEBYSIDE ){
      DiffBuilder *pBuilder;
      if( pCfg->diffFlags & DIFF_HTML ){
        pBuilder = dfsplitNew(pOut);
      }else{
        pBuilder = dfsbsNew(pOut, pCfg);
      }
      formatDiff(&c, pCfg, pBuilder);
    }else if( pCfg->diffFlags & DIFF_DEBUG ){
      DiffBuilder *pBuilder = dfdebugNew(pOut);
      formatDiff(&c, pCfg, pBuilder);
    }else if( pCfg->diffFlags & DIFF_HTML ){
      DiffBuilder *pBuilder = dfunifiedNew(pOut);
      formatDiff(&c, pCfg, pBuilder);
    }else{
      contextDiff(&c, pOut, pCfg);
    }
    fossil_free(c.aFrom);
    fossil_free(c.aTo);
    fossil_free(c.aEdit);
    return 0;
  }else{
    /* If a context diff is not requested, then return the
    ** array of COPY/DELETE/INSERT triples.
    */
    free(c.aFrom);
    free(c.aTo);
    return c.aEdit;
  }
}

/*
** Initialize the DiffConfig object using command-line options.
**
** Process diff-related command-line options and return an appropriate
** "diffFlags" integer.
**
**   --brief                      Show filenames only        DIFF_BRIEF
**   -c|--context N               N lines of context.        DIFF_CONTEXT_MASK
**   --html                       Format for HTML            DIFF_HTML
**   --invert                     Invert the diff            DIFF_INVERT
**   -n|--linenum                 Show line numbers          DIFF_LINENO
**   --noopt                      Disable optimization       DIFF_NOOPT
**   --numstat                    Show change counts         DIFF_NUMSTAT
**   --strip-trailing-cr          Strip trailing CR          DIFF_STRIP_EOLCR
**   --unified                    Unified diff.              ~DIFF_SIDEBYSIDE
**   -w|--ignore-all-space        Ignore all whitespaces     DIFF_IGNORE_ALLWS
**   -W|--width N                 N character lines.         DIFF_WIDTH_MASK
**   -y|--side-by-side            Side-by-side diff.         DIFF_SIDEBYSIDE
**   -Z|--ignore-trailing-space   Ignore eol-whitespaces     DIFF_IGNORE_EOLWS
*/
void diff_options(DiffConfig *pCfg, int isGDiff){
  u64 diffFlags = 0;
  const char *z;
  int f;

  memset(pCfg, 0, sizeof(*pCfg));
  if( find_option("ignore-trailing-space","Z",0)!=0 ){
    diffFlags = DIFF_IGNORE_EOLWS;
  }
  if( find_option("ignore-all-space","w",0)!=0 ){
    diffFlags = DIFF_IGNORE_ALLWS; /* stronger than DIFF_IGNORE_EOLWS */
  }
  if( find_option("strip-trailing-cr",0,0)!=0 ){

    diffFlags |= DIFF_TCL;
  }

  /* Undocumented and unsupported flags used for development
  ** debugging and analysis: */
  if( find_option("debug",0,0)!=0 ) diffFlags |= DIFF_DEBUG;
  if( find_option("raw",0,0)!=0 )   diffFlags |= DIFF_RAW;
  pCfg->diffFlags = diffFlags;
}

/*
** COMMAND: test-diff
** COMMAND: xdiff
**
** Usage: %fossil xdiff [options] FILE1 FILE2

** This command prints the differences between the two files FILE1 and FILE2.
** all of the usual diff formatting options (--tk, --by, -c N, etc.) apply.
** See the "diff" command for a full list of command-line options.
**
** This command used to be called "test-diff".  The older "test-diff" spelling
** still works, for compatibility.
*/
void xdiff_cmd(void){
  Blob a, b, out;

  const char *zRe;           /* Regex filter for diff output */

  DiffConfig DCfg;

  if( find_option("tk",0,0)!=0 ){
    diff_tk("xdiff", 2);
    return;
  }
  find_option("i",0,0);
  find_option("v",0,0);
  diff_options(&DCfg, 0);
  zRe = find_option("regexp","e",1);
  if( zRe ){
    const char *zErr = re_compile(&DCfg.pRe, zRe, 0);
    if( zErr ) fossil_fatal("regex error: %s", zErr);
  }

  verify_all_options();
  if( g.argc!=4 ) usage("FILE1 FILE2");
  blob_zero(&out);
  diff_begin(&DCfg);
  diff_print_filenames(g.argv[2], g.argv[3], &DCfg, &out);
  blob_read_from_file(&a, g.argv[2], ExtFILE);
  blob_read_from_file(&b, g.argv[3], ExtFILE);
  text_diff(&a, &b, &out, &DCfg);
  blob_write_to_file(&out, "-");
  diff_end(&DCfg, 0);
  re_free(DCfg.pRe);
}

/**************************************************************************
** The basic difference engine is above.  What follows is the annotation
** engine.  Both are in the same file since they share many components.
*/

  }
  return 0;
}

/*
** Print the "Index:" message that patches wants to see at the top of a diff.
*/
void diff_print_index(const char *zFile, DiffConfig *pCfg, Blob *diffBlob){
  if( (pCfg->diffFlags &
          (DIFF_SIDEBYSIDE|DIFF_BRIEF|DIFF_NUMSTAT|DIFF_JSON|
           DIFF_WEBPAGE|DIFF_TCL))==0
  ){
    char *z = mprintf("Index: %s\n%.66c\n", zFile, '=');
    if( !diffBlob ){
      fossil_print("%s", z);
    }else{
      blob_appendf(diffBlob, "%s", z);
    }
    fossil_free(z);
  }
}

/*
** Print the +++/--- filename lines or whatever filename information
** is appropriate for the output format.
*/
void diff_print_filenames(
  const char *zLeft,      /* Name of the left file */
  const char *zRight,     /* Name of the right file */
  DiffConfig *pCfg,       /* Diff configuration */
  Blob *diffBlob          /* Write to this blob, or stdout of this is NULL */
){
  char *z = 0;
  u64 diffFlags = pCfg->diffFlags;
  if( diffFlags & (DIFF_BRIEF|DIFF_RAW) ){
    /* no-op */
  }else if( diffFlags & DIFF_DEBUG ){
    fossil_print("FILE-LEFT   %s\nFILE-RIGHT  %s\n",
       zLeft, zRight);
  }else if( diffFlags & DIFF_WEBPAGE ){
    if( fossil_strcmp(zLeft,zRight)==0 ){
      z = mprintf("<h1>%h</h1>\n", zLeft);
    }else{
      z = mprintf("<h1>%h &lrarr; %h</h1>\n", zLeft, zRight);
    }
  }else if( diffFlags & (DIFF_TCL|DIFF_JSON) ){
    Blob *pOut;
    Blob x;
    if( diffBlob ){
      pOut = diffBlob;
    }else{
      blob_init(&x, 0, 0);
      pOut = &x;
    }
    if( diffFlags & DIFF_TCL ){
      blob_append(pOut, "FILE ", 5);
      blob_append_tcl_literal(pOut, zLeft, (int)strlen(zLeft));
      blob_append_char(pOut, ' ');
      blob_append_tcl_literal(pOut, zRight, (int)strlen(zRight));
      blob_append_char(pOut, '\n');
    }else{
      blob_trim(pOut);
      blob_append(pOut, (pCfg->nFile==0 ? "[{" : ",\n{"), -1);
      pCfg->nFile++;
      blob_append(pOut, "\n  \"leftname\":", -1);
      blob_append_json_literal(pOut, zLeft, (int)strlen(zLeft));
      blob_append(pOut, ",\n  \"rightname\":", -1);
      blob_append_json_literal(pOut, zRight, (int)strlen(zRight));
      blob_append(pOut, ",\n  \"diff\":\n", -1);
    }
    if( !diffBlob ){
      fossil_print("%s", blob_str(pOut));
      blob_reset(&x);
    }
    return;
  }else if( diffFlags & DIFF_SIDEBYSIDE ){
    int w = diff_width(pCfg);
    int n1 = strlen(zLeft);
    int n2 = strlen(zRight);
    int x;
    if( n1==n2 && fossil_strcmp(zLeft,zRight)==0 ){
      if( n1>w*2 ) n1 = w*2;
      x = w*2+17 - (n1+2);
      z = mprintf("%.*c %.*s %.*c\n",

;
const char zWebpageEnd[] = 
@ </body>
@ </html>
;

/*
** State variables used by the --browser option for diff.  These must
** be static variables, not elements of DiffConfig, since they are
** used by the interrupt handler.
*/
static char *tempDiffFilename;  /* File holding the diff HTML */
static FILE *diffOut;           /* Open to write into tempDiffFilename */

/* Amount of delay (in milliseconds) between launching the
** web browser and deleting the temporary file used by --browser
*/

**
** For --browser, redirect stdout to a temporary file that will
** hold the result.  Make arrangements to delete that temporary
** file if the diff is interrupted.
**
** For --browser and --webpage, output the HTML header.
*/
void diff_begin(DiffConfig *pCfg){
  if( (pCfg->diffFlags & DIFF_BROWSER)!=0 ){
    tempDiffFilename = fossil_temp_filename();
    tempDiffFilename = sqlite3_mprintf("%z.html", tempDiffFilename);
    diffOut = fossil_freopen(tempDiffFilename,"wb",stdout);
    if( diffOut==0 ){
      fossil_fatal("unable to create temporary file \"%s\"", 
                   tempDiffFilename);
    }
#ifndef _WIN32
    signal(SIGINT, diff_www_interrupt);
#else
    SetConsoleCtrlHandler(diff_console_ctrl_handler, TRUE);
#endif
  }
  if( (pCfg->diffFlags & DIFF_WEBPAGE)!=0 ){
    fossil_print("%s",zWebpageHdr);
    fflush(stdout);
  }
}

/* Do any final output required by a diff and complete the diff
** process.
**
** For --browser and --webpage, output any javascript required by 
** the diff.  (Currently JS is only needed for side-by-side diffs).
**
** For --browser, close the connection to the temporary file, then
** launch a web browser to view the file.  After a delay
** of FOSSIL_BROWSER_DIFF_DELAY milliseconds, delete the temp file.
*/
void diff_end(DiffConfig *pCfg, int nErr){
  if( (pCfg->diffFlags & DIFF_WEBPAGE)!=0 ){
    if( pCfg->diffFlags & DIFF_SIDEBYSIDE ){
      const unsigned char *zJs = builtin_file("diff.js", 0);
      fossil_print("<script>\n%s</script>\n", zJs);
    }
    fossil_print("%s", zWebpageEnd);
  }
  if( (pCfg->diffFlags & DIFF_BROWSER)!=0 && nErr==0 ){
    char *zCmd = mprintf("%s %$", fossil_web_browser(), tempDiffFilename);
    fclose(diffOut);
    diffOut = fossil_freopen(NULL_DEVICE, "wb", stdout);
    fossil_system(zCmd);
    fossil_free(zCmd);
    diffOut = 0;
    sqlite3_sleep(FOSSIL_BROWSER_DIFF_DELAY);
    file_delete(tempDiffFilename);
    sqlite3_free(tempDiffFilename);
    tempDiffFilename = 0;
  }
  if( (pCfg->diffFlags & DIFF_JSON)!=0 && pCfg->nFile>0 ){
    fossil_print("]\n");
  }
}

/*
** Show the difference between two files, one in memory and one on disk.
**
** The difference is the set of edits needed to transform pFile1 into

  Blob *pFile1,             /* In memory content to compare from */
  int isBin1,               /* Does the 'from' content appear to be binary */
  const char *zFile2,       /* On disk content to compare to */
  const char *zName,        /* Display name of the file */
  const char *zDiffCmd,     /* Command for comparison */
  const char *zBinGlob,     /* Treat file names matching this as binary */
  int fIncludeBinary,       /* Include binary files for external diff */
  DiffConfig *pCfg,         /* Flags to control the diff */
  int fSwapDiff,            /* Diff from Zfile2 to Pfile1 */
  Blob *diffBlob            /* Blob to store diff output */
){
  if( zDiffCmd==0 ){
    Blob out;                 /* Diff output text */
    Blob file2;               /* Content of zFile2 */
    const char *zName2;       /* Name of zFile2 for display */

    /* Read content of zFile2 into memory */
    blob_zero(&file2);
    if( file_size(zFile2, ExtFILE)<0 ){
      zName2 = NULL_DEVICE;
    }else{
      blob_read_from_file(&file2, zFile2, ExtFILE);
      zName2 = zName;
    }

    /* Compute and output the differences */
    if( pCfg->diffFlags & DIFF_BRIEF ){
      if( blob_compare(pFile1, &file2) ){
        fossil_print("CHANGED  %s\n", zName);
      }
    }else{
      blob_zero(&out);
      if( fSwapDiff ){
        text_diff(&file2, pFile1, &out, pCfg);
      }else{
        text_diff(pFile1, &file2, &out, pCfg);
      }
      if( blob_size(&out) ){
        if( pCfg->diffFlags & DIFF_NUMSTAT ){
          if( !diffBlob ){
            fossil_print("%s %s\n", blob_str(&out), zName);
          }else{
            blob_appendf(diffBlob, "%s %s\n", blob_str(&out), zName);
          }
        }else{
          diff_print_filenames(zName, zName2, pCfg, diffBlob);
          if( !diffBlob ){

            fossil_print("%s\n", blob_str(&out));
          }else{

            blob_appendf(diffBlob, "%s\n", blob_str(&out));
          }
        }
      }
      blob_reset(&out);
    }

  Blob *pFile2,             /* In memory content to compare to */
  int isBin1,               /* Does the 'from' content appear to be binary */
  int isBin2,               /* Does the 'to' content appear to be binary */
  const char *zName,        /* Display name of the file */
  const char *zDiffCmd,     /* Command for comparison */
  const char *zBinGlob,     /* Treat file names matching this as binary */
  int fIncludeBinary,       /* Include binary files for external diff */
  DiffConfig *pCfg          /* Diff flags */
){
  if( pCfg->diffFlags & DIFF_BRIEF ) return;
  if( zDiffCmd==0 ){
    Blob out;      /* Diff output text */

    blob_zero(&out);
    text_diff(pFile1, pFile2, &out, pCfg);
    if( pCfg->diffFlags & DIFF_NUMSTAT ){
      fossil_print("%s %s\n", blob_str(&out), zName);
    }else{
      diff_print_filenames(zName, zName, pCfg, 0);
      fossil_print("%s\n", blob_str(&out));
    }

    /* Release memory resources */
    blob_reset(&out);
  }else{
    Blob cmd;

** will be skipped in addition to files that may contain binary content.
*/
void diff_against_disk(
  const char *zFrom,        /* Version to difference from */
  const char *zDiffCmd,     /* Use this diff command.  NULL for built-in */
  const char *zBinGlob,     /* Treat file names matching this as binary */
  int fIncludeBinary,       /* Treat file names matching this as binary */
  DiffConfig *pCfg,         /* Flags controlling diff output */
  FileDirList *pFileDir,    /* Which files to diff */
  Blob *diffBlob            /* Blob to output diff instead of stdout */
){
  int vid;
  Blob sql;
  Stmt q;
  int asNewFile;            /* Treat non-existant files as empty files */
  int isNumStat;            /* True for --numstat */

  asNewFile = (pCfg->diffFlags & (DIFF_VERBOSE|DIFF_NUMSTAT|DIFF_HTML))!=0;
  isNumStat = (pCfg->diffFlags & (DIFF_NUMSTAT|DIFF_TCL|DIFF_HTML))!=0;
  vid = db_lget_int("checkout", 0);
  vfile_check_signature(vid, CKSIG_ENOTFILE);
  blob_zero(&sql);
  db_begin_transaction();
  if( zFrom ){
    int rid = name_to_typed_rid(zFrom, "ci");
    if( !is_a_version(rid) ){

      srcid = 0;
      if( !asNewFile ){ showDiff = 0; }
    }
    if( showDiff ){
      Blob content;
      int isBin;
      if( !isLink != !file_islink(zFullName) ){
        diff_print_index(zPathname, pCfg, 0);
        diff_print_filenames(zPathname, zPathname, pCfg, 0);
        fossil_print("%s",DIFF_CANNOT_COMPUTE_SYMLINK);
        continue;
      }
      if( srcid>0 ){
        content_get(srcid, &content);
      }else{
        blob_zero(&content);
      }
      isBin = fIncludeBinary ? 0 : looks_like_binary(&content);
      diff_print_index(zPathname, pCfg, diffBlob);
      diff_file(&content, isBin, zFullName, zPathname, zDiffCmd,
                zBinGlob, fIncludeBinary, pCfg, 0, diffBlob);
      blob_reset(&content);
    }
    blob_reset(&fname);
  }
  db_finalize(&q);
  db_end_transaction(1);  /* ROLLBACK */
}

** for file names to treat as binary.  If fIncludeBinary is zero, these files
** will be skipped in addition to files that may contain binary content.
*/
static void diff_against_undo(
  const char *zDiffCmd,     /* Use this diff command.  NULL for built-in */
  const char *zBinGlob,     /* Treat file names matching this as binary */
  int fIncludeBinary,       /* Treat file names matching this as binary */
  DiffConfig *pCfg,         /* Flags controlling diff output */
  FileDirList *pFileDir     /* List of files and directories to diff */
){
  Stmt q;
  Blob content;
  db_prepare(&q, "SELECT pathname, content FROM undo");
  blob_init(&content, 0, 0);
  while( db_step(&q)==SQLITE_ROW ){
    char *zFullName;
    const char *zFile = (const char*)db_column_text(&q, 0);
    if( !file_dir_match(pFileDir, zFile) ) continue;
    zFullName = mprintf("%s%s", g.zLocalRoot, zFile);
    db_column_blob(&q, 1, &content);
    diff_file(&content, 0, zFullName, zFile,
              zDiffCmd, zBinGlob, fIncludeBinary, pCfg, 0, 0);
    fossil_free(zFullName);
    blob_reset(&content);
  }
  db_finalize(&q);
}

/*

*/
static void diff_manifest_entry(
  struct ManifestFile *pFrom,
  struct ManifestFile *pTo,
  const char *zDiffCmd,
  const char *zBinGlob,
  int fIncludeBinary,
  DiffConfig *pCfg
){
  Blob f1, f2;
  int isBin1, isBin2;
  int rid;
  const char *zName;
  if( pFrom ){
    zName = pFrom->zName;
  }else if( pTo ){
    zName = pTo->zName;
  }else{
    zName = DIFF_NO_NAME;
  }
  if( pCfg->diffFlags & DIFF_BRIEF ) return;
  diff_print_index(zName, pCfg, 0);
  if( pFrom ){
    rid = uuid_to_rid(pFrom->zUuid, 0);
    content_get(rid, &f1);
  }else{
    blob_zero(&f1);
  }
  if( pTo ){
    rid = uuid_to_rid(pTo->zUuid, 0);
    content_get(rid, &f2);
  }else{
    blob_zero(&f2);
  }
  isBin1 = fIncludeBinary ? 0 : looks_like_binary(&f1);
  isBin2 = fIncludeBinary ? 0 : looks_like_binary(&f2);
  diff_file_mem(&f1, &f2, isBin1, isBin2, zName, zDiffCmd,
                zBinGlob, fIncludeBinary, pCfg);
  blob_reset(&f1);
  blob_reset(&f2);
}

/*
** Output the differences between two check-ins.
**
** Use the internal diff logic if zDiffCmd is NULL.  Otherwise call the
** command zDiffCmd to do the diffing.
**
** When using an external diff program, zBinGlob contains the GLOB patterns
** for file names to treat as binary.  If fIncludeBinary is zero, these files
** will be skipped in addition to files that may contain binary content.
*/
static void diff_two_versions(
  const char *zFrom,
  const char *zTo,
  const char *zDiffCmd,
  const char *zBinGlob,
  int fIncludeBinary,
  DiffConfig *pCfg,
  FileDirList *pFileDir
){
  Manifest *pFrom, *pTo;
  ManifestFile *pFromFile, *pToFile;
  int asNewFlag = (pCfg->diffFlags & (DIFF_VERBOSE|DIFF_NUMSTAT))!=0 ? 1 : 0;

  pFrom = manifest_get_by_name(zFrom, 0);
  manifest_file_rewind(pFrom);
  pFromFile = manifest_file_next(pFrom,0);
  pTo = manifest_get_by_name(zTo, 0);
  manifest_file_rewind(pTo);
  pToFile = manifest_file_next(pTo,0);

  while( pFromFile || pToFile ){
    int cmp;
    if( pFromFile==0 ){
      cmp = +1;
    }else if( pToFile==0 ){
      cmp = -1;
    }else{
      cmp = fossil_strcmp(pFromFile->zName, pToFile->zName);
    }
    if( cmp<0 ){
      if( file_dir_match(pFileDir, pFromFile->zName) ){
        if( (pCfg->diffFlags & (DIFF_NUMSTAT|DIFF_HTML))==0 ){
          fossil_print("DELETED %s\n", pFromFile->zName);
        }
        if( asNewFlag ){
          diff_manifest_entry(pFromFile, 0, zDiffCmd, zBinGlob,
                              fIncludeBinary, pCfg);
        }
      }
      pFromFile = manifest_file_next(pFrom,0);
    }else if( cmp>0 ){
      if( file_dir_match(pFileDir, pToFile->zName) ){
        if( (pCfg->diffFlags &
             (DIFF_NUMSTAT|DIFF_HTML|DIFF_TCL|DIFF_JSON))==0 ){
          fossil_print("ADDED   %s\n", pToFile->zName);
        }
        if( asNewFlag ){
          diff_manifest_entry(0, pToFile, zDiffCmd, zBinGlob,
                              fIncludeBinary, pCfg);
        }
      }
      pToFile = manifest_file_next(pTo,0);
    }else if( fossil_strcmp(pFromFile->zUuid, pToFile->zUuid)==0 ){
      /* No changes */
      (void)file_dir_match(pFileDir, pFromFile->zName); /* Record name usage */
      pFromFile = manifest_file_next(pFrom,0);
      pToFile = manifest_file_next(pTo,0);
    }else{
      if( file_dir_match(pFileDir, pToFile->zName) ){
        if( pCfg->diffFlags & DIFF_BRIEF ){
          fossil_print("CHANGED %s\n", pFromFile->zName);
        }else{
          diff_manifest_entry(pFromFile, pToFile, zDiffCmd, zBinGlob,
                              fIncludeBinary, pCfg);
        }
      }
      pFromFile = manifest_file_next(pFrom,0);
      pToFile = manifest_file_next(pTo,0);
    }
  }
  manifest_destroy(pFrom);

  const char *zTo;           /* Target version number */
  const char *zCheckin;      /* Check-in version number */
  const char *zBranch;       /* Branch to diff */
  const char *zDiffCmd = 0;  /* External diff command. NULL for internal diff */
  const char *zBinGlob = 0;  /* Treat file names matching this as binary */
  int fIncludeBinary = 0;    /* Include binary files for external diff */
  int againstUndo = 0;       /* Diff against files in the undo buffer */

  FileDirList *pFileDir = 0; /* Restrict the diff to these files */
  DiffConfig DCfg;           /* Diff configuration object */

  if( find_option("tk",0,0)!=0 || has_option("tclsh") ){
    diff_tk("diff", 2);
    return;
  }
  isGDiff = g.argv[1][0]=='g';
  isInternDiff = find_option("internal","i",0)!=0;
  zFrom = find_option("from", "r", 1);
  zTo = find_option("to", 0, 1);
  zCheckin = find_option("checkin", 0, 1);
  zBranch = find_option("branch", 0, 1);
  againstUndo = find_option("undo",0,0)!=0;
  diff_options(&DCfg, isGDiff);
  verboseFlag = find_option("verbose","v",0)!=0;
  if( !verboseFlag ){
    verboseFlag = find_option("new-file","N",0)!=0; /* deprecated */
  }
  if( verboseFlag ) DCfg.diffFlags |= DIFF_VERBOSE;
  if( againstUndo && ( zFrom!=0 || zTo!=0 || zCheckin!=0 || zBranch!=0) ){
    fossil_fatal("cannot use --undo together with --from, --to, --checkin,"
                 " or --branch");
  }
  if( zBranch ){
    if( zTo || zFrom || zCheckin ){
      fossil_fatal("cannot use --from, --to, or --checkin with --branch");

    db_must_be_within_tree();
  }else if( zFrom==0 ){
    fossil_fatal("must use --from if --to is present");
  }else{
    db_find_and_open_repository(0, 0);
  }
  if( !isInternDiff
   && (DCfg.diffFlags & DIFF_HTML)==0 /* External diff can't generate HTML */
  ){
    zDiffCmd = find_option("command", 0, 1);
    if( zDiffCmd==0 ) zDiffCmd = diff_command_external(isGDiff);
  }
  zBinGlob = diff_get_binary_glob();
  fIncludeBinary = diff_include_binary_files();
  determine_exec_relative_option(1);

      "SELECT uuid FROM blob, plink"
      " WHERE plink.cid=%d AND plink.isprim AND plink.pid=blob.rid",
      ridTo);
    if( zFrom==0 ){
      fossil_fatal("check-in %s has no parent", zTo);
    }
  }
  diff_begin(&DCfg);
  if( againstUndo ){
    if( db_lget_int("undo_available",0)==0 ){
      fossil_print("No undo or redo is available\n");
      return;
    }
    diff_against_undo(zDiffCmd, zBinGlob, fIncludeBinary,
                      &DCfg, pFileDir);
  }else if( zTo==0 ){
    diff_against_disk(zFrom, zDiffCmd, zBinGlob, fIncludeBinary,
                      &DCfg, pFileDir, 0);
  }else{
    diff_two_versions(zFrom, zTo, zDiffCmd, zBinGlob, fIncludeBinary,
                      &DCfg, pFileDir);
  }
  if( pFileDir ){
    int i;
    for(i=0; pFileDir[i].zName; i++){
      if( pFileDir[i].nUsed==0
       && strcmp(pFileDir[0].zName,".")!=0
       && !file_isdir(g.argv[i+2], ExtFILE)
      ){
        fossil_fatal("not found: '%s'", g.argv[i+2]);
      }
      fossil_free(pFileDir[i].zName);
    }
    fossil_free(pFileDir);
  }
  diff_end(&DCfg, 0);
  if ( DCfg.diffFlags & DIFF_NUMSTAT ){
    fossil_print("%10d %10d TOTAL over %d changed files\n", 
                 g.diffCnt[1], g.diffCnt[2], g.diffCnt[0]);
  }
}

/*
** WEBPAGE: vpatch
** URL: /vpatch?from=FROM&to=TO
**
** Show a patch that goes from check-in FROM to check-in TO.
*/
void vpatch_page(void){
  const char *zFrom = P("from");
  const char *zTo = P("to");
  DiffConfig DCfg;
  login_check_credentials();
  if( !g.perm.Read ){ login_needed(g.anon.Read); return; }
  if( zFrom==0 || zTo==0 ) fossil_redirect_home();

  cgi_set_content_type("text/plain");
  diff_config_init(&DCfg, DIFF_VERBOSE);
  diff_two_versions(zFrom, zTo, 0, 0, 0, &DCfg, 0);
}

/*
** Append the difference between artifacts to the output
*/
static void append_diff(
  const char *zFrom,    /* Diff from this artifact */
  const char *zTo,      /*  ... to this artifact */
  DiffConfig *pCfg      /* The diff configuration */

){
  int fromid;
  int toid;
  Blob from, to;
  if( zFrom ){
    fromid = uuid_to_rid(zFrom, 0);
    content_get(fromid, &from);
  }else{
    blob_zero(&from);
  }
  if( zTo ){
    toid = uuid_to_rid(zTo, 0);
    content_get(toid, &to);
  }else{
    blob_zero(&to);
  }
  if( pCfg->diffFlags & DIFF_SIDEBYSIDE ){
    pCfg->diffFlags |= DIFF_HTML | DIFF_NOTTOOBIG;
  }else{
    pCfg->diffFlags |= DIFF_LINENO | DIFF_HTML | DIFF_NOTTOOBIG;
  }
  text_diff(&from, &to, cgi_output_blob(), pCfg);
  blob_reset(&from);
  blob_reset(&to);
}

/*
** Write a line of web-page output that shows changes that have occurred
** to a file between two check-ins.
*/
static void append_file_change_line(
  const char *zCkin,    /* The checkin on which the change occurs */
  const char *zName,    /* Name of the file that has changed */
  const char *zOld,     /* blob.uuid before change.  NULL for added files */
  const char *zNew,     /* blob.uuid after change.  NULL for deletes */
  const char *zOldName, /* Prior name.  NULL if no name change. */
  DiffConfig *pCfg,     /* Flags for text_diff() or NULL to omit all */

  int mperm             /* executable or symlink permission for zNew */
){
  @ <p>
  if( !g.perm.Hyperlink ){
    if( zNew==0 ){
      @ Deleted %h(zName).
    }else if( zOld==0 ){

        @ %h(zName) became a symlink.
      }else{
        @ %h(zName) became a regular file.
      }
    }else{
      @ Changes to %h(zName).
    }
    if( pCfg ){
      append_diff(zOld, zNew, pCfg);
    }
  }else{
    if( zOld && zNew ){
      if( fossil_strcmp(zOld, zNew)!=0 ){
        @ Modified %z(href("%R/finfo?name=%T&m=%!S&ci=%!S",zName,zNew,zCkin))\
        @ %h(zName)</a>
        @ from %z(href("%R/artifact/%!S",zOld))[%S(zOld)]</a>

    }else if( zOld ){
      @ Deleted %z(href("%R/finfo?name=%T&m=%!S&ci=%!S",zName,zOld,zCkin))\
      @ %h(zName)</a> version %z(href("%R/artifact/%!S",zOld))[%S(zOld)]</a>.
    }else{
      @ Added %z(href("%R/finfo?name=%T&m=%!S&ci=%!S",zName,zNew,zCkin))\
      @ %h(zName)</a> version %z(href("%R/artifact/%!S",zNew))[%S(zNew)]</a>.
    }
    if( pCfg ){
      append_diff(zOld, zNew, pCfg);
    }else if( zOld && zNew && fossil_strcmp(zOld,zNew)!=0 ){
      @ &nbsp;&nbsp;
      @ %z(href("%R/fdiff?v1=%!S&v2=%!S",zOld,zNew))[diff]</a>
    }
  }
  @ </p>
}

/*
** Generate javascript to enhance HTML diffs.
*/
void append_diff_javascript(int sideBySide){
  if( !sideBySide ) return;
  builtin_request_js("diff.js");
}

/*
** Construct an appropriate diffFlag for text_diff() based on query
** parameters and the to boolean arguments.
*/
DiffConfig *construct_diff_flags(int diffType, DiffConfig *pCfg){
  u64 diffFlags = 0;  /* Zero means do not show any diff */
  if( diffType>0 ){
    int x;
    if( diffType==2 ){
      diffFlags = DIFF_SIDEBYSIDE;

      /* "dw" query parameter determines width of each column */

    x = atoi(PD("dc","7"));
    if( x<0 || x>DIFF_CONTEXT_MASK ) x = DIFF_CONTEXT_MASK;
    diffFlags += x;

    /* The "noopt" parameter disables diff optimization */
    if( PD("noopt",0)!=0 ) diffFlags |= DIFF_NOOPT;
    diffFlags |= DIFF_STRIP_EOLCR;
    diff_config_init(pCfg, diffFlags);
    return pCfg;
  }else{
    diff_config_init(pCfg, 0);
    return 0;
  }
}

/*
** WEBPAGE: ci_tags
** URL:    /ci_tags?name=ARTIFACTID
**
** Show all tags and properties for a given check-in.

** or a tag or branch name that identifies the check-in.
*/
void ci_page(void){
  Stmt q1, q2, q3;
  int rid;
  int isLeaf;
  int diffType;        /* 0: no diff,  1: unified,  2: side-by-side */

  const char *zName;   /* Name of the check-in to be displayed */
  const char *zUuid;   /* Hash of zName, found via blob.uuid */
  const char *zParent; /* Hash of the parent check-in (if any) */
  const char *zRe;     /* regex parameter */
  ReCompiled *pRe = 0; /* regex */
  const char *zW;               /* URL param for ignoring whitespace */
  const char *zPage = "vinfo";  /* Page that shows diffs */
  const char *zPageHide = "ci"; /* Page that hides diffs */
  const char *zBrName;          /* Branch name */
  DiffConfig DCfg,*pCfg;        /* Type of diff */

  login_check_credentials();
  if( !g.perm.Read ){ login_needed(g.anon.Read); return; }
  style_set_current_feature("vinfo");
  zName = P("name");
  rid = name_to_rid_www("name");
  if( rid==0 ){

    wiki_render_associated("checkin", zUuid, 0);
  }
  render_backlink_graph(zUuid, "<div class=\"section\">References</div>\n");
  @ <div class="section">Context</div>
  render_checkin_context(rid, 0, 0, 0);
  @ <div class="section">Changes</div>
  @ <div class="sectionmenu">
  pCfg = construct_diff_flags(diffType, &DCfg);
  DCfg.pRe = pRe;  
  zW = (DCfg.diffFlags&DIFF_IGNORE_ALLWS)?"&w":"";
  if( diffType!=0 ){
    @ %z(chref("button","%R/%s/%T?diff=0",zPageHide,zName))\
    @ Hide&nbsp;Diffs</a>
  }
  if( diffType!=1 ){
    @ %z(chref("button","%R/%s/%T?diff=1%s",zPage,zName,zW))\
    @ Unified&nbsp;Diffs</a>

  while( db_step(&q3)==SQLITE_ROW ){
    const char *zName = db_column_text(&q3,0);
    int mperm = db_column_int(&q3, 1);
    const char *zOld = db_column_text(&q3,2);
    const char *zNew = db_column_text(&q3,3);
    const char *zOldName = db_column_text(&q3, 4);
    append_file_change_line(zUuid, zName, zOld, zNew, zOldName, 
                            pCfg,mperm);
  }
  db_finalize(&q3);
  append_diff_javascript(diffType);
  builtin_fossil_js_bundle_or("info-diff",NULL);
  style_finish_page();
}

/*
** WEBPAGE: winfo
** URL:  /winfo?name=HASH

**   inv             "Invert".  Exchange the roles of from= and to=
**
** Show all differences between two check-ins.
*/
void vdiff_page(void){
  int ridFrom, ridTo;
  int diffType = 0;        /* 0: none, 1: unified, 2: side-by-side */

  Manifest *pFrom, *pTo;
  ManifestFile *pFileFrom, *pFileTo;
  const char *zBranch;
  const char *zFrom;
  const char *zTo;
  const char *zRe;
  const char *zGlob;
  char *zMergeOrigin = 0;
  ReCompiled *pRe = 0;
  DiffConfig DCfg, *pCfg = 0;
  int graphFlags = 0;
  Blob qp;
  int bInvert = PB("inv");

  login_check_credentials();
  if( !g.perm.Read ){ login_needed(g.anon.Read); return; }
  login_anonymous_available();

      blob_appendf(&qp, "&glob=%T", zGlob);
    }
  }
  if( PB("nc") ){
    graphFlags |= TIMELINE_NOCOLOR;
    blob_appendf(&qp, "&nc");
  }
  pCfg = construct_diff_flags(diffType, &DCfg);
  if( DCfg.diffFlags & DIFF_IGNORE_ALLWS ){
    blob_appendf(&qp, "&w");
  }
  style_set_current_feature("vdiff");
  if( zBranch==0 ){
    style_submenu_element("Path", "%R/timeline?me=%T&you=%T", zFrom, zTo);
  }
  if( diffType!=0 ){

  if( zBranch==0 ){
    style_submenu_element("Invert","%R/vdiff?diff=%d&inv&%b", diffType, &qp);
  }
  if( zGlob ){
    style_submenu_element("Clear glob", "%R/vdiff?diff=%d&%b", diffType, &qp);
  }else{
    style_submenu_element("Patch", "%R/vpatch?from=%T&to=%T%s", zFrom, zTo,
           (DCfg.diffFlags & DIFF_IGNORE_ALLWS)?"&w":"");
  }
  if( diffType!=0 ){
    style_submenu_checkbox("w", "Ignore Whitespace", 0, 0);
  }
  if( zBranch ){
    style_header("Changes On Branch %h", zBranch);
  }else{

  }
  blob_reset(&qp);

  manifest_file_rewind(pFrom);
  pFileFrom = manifest_file_next(pFrom, 0);
  manifest_file_rewind(pTo);
  pFileTo = manifest_file_next(pTo, 0);
  DCfg.pRe = pRe;
  while( pFileFrom || pFileTo ){
    int cmp;
    if( pFileFrom==0 ){
      cmp = +1;
    }else if( pFileTo==0 ){
      cmp = -1;
    }else{
      cmp = fossil_strcmp(pFileFrom->zName, pFileTo->zName);
    }
    if( cmp<0 ){
      if( !zGlob || sqlite3_strglob(zGlob, pFileFrom->zName)==0 ){
        append_file_change_line(zFrom, pFileFrom->zName,
                                pFileFrom->zUuid, 0, 0, pCfg, 0);
      }
      pFileFrom = manifest_file_next(pFrom, 0);
    }else if( cmp>0 ){
      if( !zGlob || sqlite3_strglob(zGlob, pFileTo->zName)==0 ){
        append_file_change_line(zTo, pFileTo->zName,
                                0, pFileTo->zUuid, 0, pCfg,
                                manifest_file_mperm(pFileTo));
      }
      pFileTo = manifest_file_next(pTo, 0);
    }else if( fossil_strcmp(pFileFrom->zUuid, pFileTo->zUuid)==0 ){
      pFileFrom = manifest_file_next(pFrom, 0);
      pFileTo = manifest_file_next(pTo, 0);
    }else{
      if(!zGlob || (sqlite3_strglob(zGlob, pFileFrom->zName)==0
                || sqlite3_strglob(zGlob, pFileTo->zName)==0) ){
        append_file_change_line(zFrom, pFileFrom->zName,
                                pFileFrom->zUuid,
                                pFileTo->zUuid, 0, pCfg,
                                manifest_file_mperm(pFileTo));
      }
      pFileFrom = manifest_file_next(pFrom, 0);
      pFileTo = manifest_file_next(pTo, 0);
    }
  }
  manifest_destroy(pFrom);

  char *zV1;
  char *zV2;
  const char *zRe;
  ReCompiled *pRe = 0;
  u64 diffFlags;
  u32 objdescFlags = 0;
  int verbose = PB("verbose");
  DiffConfig DCfg;

  login_check_credentials();
  if( !g.perm.Read ){ login_needed(g.anon.Read); return; }
  diffType = preferred_diff_type();
  if( P("from") && P("to") ){
    v1 = artifact_from_ci_and_filename("from");
    v2 = artifact_from_ci_and_filename("to");

  }
  if( v1==0 || v2==0 ) fossil_redirect_home();
  zRe = P("regex");
  if( zRe ) re_compile(&pRe, zRe, 0);
  if( verbose ) objdescFlags |= OBJDESC_DETAIL;
  if( isPatch ){
    Blob c1, c2, *pOut;
    DiffConfig DCfg;
    pOut = cgi_output_blob();
    cgi_set_content_type("text/plain");
    diffFlags = 4;
    content_get(v1, &c1);
    content_get(v2, &c2);
    diff_config_init(&DCfg, diffFlags);
    DCfg.pRe = pRe;
    text_diff(&c1, &c2, pOut, &DCfg);
    blob_reset(&c1);
    blob_reset(&c2);
    return;
  }

  zV1 = db_text(0, "SELECT uuid FROM blob WHERE rid=%d", v1);
  zV2 = db_text(0, "SELECT uuid FROM blob WHERE rid=%d", v2);
  construct_diff_flags(diffType, &DCfg);
  DCfg.diffFlags |= DIFF_HTML;

  style_set_current_feature("fdiff");
  style_header("Diff");
  style_submenu_checkbox("w", "Ignore Whitespace", 0, 0);
  if( diffType==2 ){
    style_submenu_element("Unified Diff", "%R/fdiff?v1=%T&v2=%T&diff=1",
                           P("v1"), P("v2"));

    object_description(v1, objdescFlags,0, 0);
    @ <h2>To Artifact %z(href("%R/artifact/%!S",zV2))[%S(zV2)]</a>:</h2>
    object_description(v2, objdescFlags,0, 0);
  }
  if( pRe ){
    @ <b>Only differences that match regular expression "%h(zRe)"
    @ are shown.</b>
    DCfg.pRe = pRe;
  }
  @ <hr />
  append_diff(zV1, zV2, &DCfg);
  append_diff_javascript(diffType);
  style_finish_page();
}

/*
** WEBPAGE: raw
** URL: /raw/ARTIFACTID

*/
cson_value * json_generate_diff(const char *zFrom, const char *zTo,
                                int nContext, char fSbs,
                                char fHtml){
  int fromid;
  int toid;
  int outLen;
  DiffConfig DCfg;
  Blob from = empty_blob, to = empty_blob, out = empty_blob;
  cson_value * rc = NULL;
  int flags = (DIFF_CONTEXT_MASK & nContext)
    | (fSbs ? DIFF_SIDEBYSIDE : 0)
    | (fHtml ? DIFF_HTML : 0);
  fromid = name_to_typed_rid(zFrom, "*");
  if(fromid<=0){
      json_set_err(FSL_JSON_E_UNRESOLVED_UUID,
                   "Could not resolve 'from' ID.");
      return NULL;
  }
  toid = name_to_typed_rid(zTo, "*");
  if(toid<=0){
      json_set_err(FSL_JSON_E_UNRESOLVED_UUID,
                   "Could not resolve 'to' ID.");
      return NULL;
  }
  content_get(fromid, &from);
  content_get(toid, &to);
  blob_zero(&out);
  diff_config_init(&DCfg, flags);
  text_diff(&from, &to, &out, &DCfg);
  blob_reset(&from);
  blob_reset(&to);
  outLen = blob_size(&out);
  if(outLen>=0){
    rc = cson_value_new_string(blob_buffer(&out),
                               (unsigned int)blob_size(&out));
  }

  char const * zV2 = NULL;
  cson_object * pay = NULL;
  int argPos = g.json.dispatchDepth;
  int r1 = 0, r2 = 0;
  Manifest * pW1 = NULL, *pW2 = NULL;
  Blob w1 = empty_blob, w2 = empty_blob, d = empty_blob;
  char const * zErrTag = NULL;
  DiffConfig DCfg;
  char * zUuid = NULL;
  if( !g.perm.Hyperlink ){
    json_set_err(FSL_JSON_E_DENIED,
                 "Requires 'h' permissions.");
    return NULL;
  }

    goto manifest;
  }

  blob_init(&w1, pW1->zWiki, -1);
  blob_zero(&w2);
  blob_init(&w2, pW2->zWiki, -1);
  blob_zero(&d);
  diff_config_init(&DCfg, DIFF_IGNORE_EOLWS | DIFF_STRIP_EOLCR);
  text_diff(&w1, &w2, &d, &DCfg);
  blob_reset(&w1);
  blob_reset(&w2);

  pay = cson_new_object();

  zUuid = json_wiki_get_uuid_for_rid( pW1->rid );
  cson_object_set(pay, "v1", json_new_string(zUuid) );

  int *aC1;              /* Changes from pPivot to pV1 */
  int *aC2;              /* Changes from pPivot to pV2 */
  int i1, i2;            /* Index into aC1[] and aC2[] */
  int nCpy, nDel, nIns;  /* Number of lines to copy, delete, or insert */
  int limit1, limit2;    /* Sizes of aC1[] and aC2[] */
  int nConflict = 0;     /* Number of merge conflicts seen so far */
  int useCrLf = 0;
  DiffConfig DCfg;

  blob_zero(pOut);         /* Merge results stored in pOut */
  
  /* If both pV1 and pV2 start with a UTF-8 byte-order-mark (BOM),
  ** keep it in the output. This should be secure enough not to cause
  ** unintended changes to the merged file and consistent with what
  ** users are using in their source files.

  ** and pPivot => pV2 (into aC2).  Each of the aC1 and aC2 arrays is
  ** an array of integer triples.  Within each triple, the first integer
  ** is the number of lines of text to copy directly from the pivot,
  ** the second integer is the number of lines of text to omit from the
  ** pivot, and the third integer is the number of lines of text that are
  ** inserted.  The edit array ends with a triple of 0,0,0.
  */
  diff_config_init(&DCfg, 0);
  aC1 = text_diff(pPivot, pV1, 0, &DCfg);
  aC2 = text_diff(pPivot, pV2, 0, &DCfg);
  if( aC1==0 || aC2==0 ){
    free(aC1);
    free(aC2);
    return -1;
  }

  blob_rewind(pV1);        /* Rewind inputs:  Needed to reconstruct output */

** Show a diff for the patch currently loaded into database "patch".
*/
static void patch_diff(
  unsigned mFlags,         /* Patch flags.  only -f is allowed */
  const char *zDiffCmd,    /* Command used for diffing */
  const char *zBinGlob,    /* GLOB pattern to determine binary files */
  int fIncludeBinary,      /* Do diffs against binary files */
  DiffConfig *pCfg         /* Diff options */
){
  int nErr = 0;
  Stmt q;
  int bWebpage = (pCfg->diffFlags & DIFF_WEBPAGE)!=0;
  Blob empty;
  blob_zero(&empty);

  if( (mFlags & PATCH_FORCE)==0 ){
    /* Check to ensure that the patch is against the repository that
    ** we have opened.
    **

      if( zBaseline ){
        fossil_fatal("the baseline of the patch (check-in %S) is not found "
                     "in the %s repository", zBaseline, g.zRepositoryName);
      }
    }
  }

  diff_begin(pCfg);
  db_prepare(&q,
     "SELECT"
       " (SELECT blob.rid FROM blob WHERE blob.uuid=chng.hash),"
       " pathname,"    /* 1: new pathname */
       " origname,"    /* 2: original pathname.  Null if not renamed */
       " delta,"       /* 3: delta.  NULL if deleted.  empty is no change */
       " hash"         /* 4: baseline hash */

      }
    }
    zName = db_column_text(&q, 1);
    rid = db_column_int(&q, 0);

    if( db_column_type(&q,3)==SQLITE_NULL ){
      if( !bWebpage ) fossil_print("DELETE %s\n", zName);
      diff_print_index(zName, pCfg, 0);
      isBin2 = 0;
      content_get(rid, &a);
      isBin1 = fIncludeBinary ? 0 : looks_like_binary(&a);
      diff_file_mem(&a, &empty, isBin1, isBin2, zName, zDiffCmd,
                    zBinGlob, fIncludeBinary, pCfg);
    }else if( rid==0 ){
      db_ephemeral_blob(&q, 3, &a);
      blob_uncompress(&a, &a);
      if( !bWebpage ) fossil_print("ADDED %s\n", zName);
      diff_print_index(zName, pCfg, 0);
      isBin1 = 0;
      isBin2 = fIncludeBinary ? 0 : looks_like_binary(&a);
      diff_file_mem(&empty, &a, isBin1, isBin2, zName, zDiffCmd,
                    zBinGlob, fIncludeBinary, pCfg);
      blob_reset(&a);
    }else if( db_column_bytes(&q, 3)>0 ){
      Blob delta;
      db_ephemeral_blob(&q, 3, &delta);
      blob_uncompress(&delta, &delta);
      content_get(rid, &a);
      blob_delta_apply(&a, &delta, &b);
      isBin1 = fIncludeBinary ? 0 : looks_like_binary(&a);
      isBin2 = fIncludeBinary ? 0 : looks_like_binary(&b);
      diff_file_mem(&a, &b, isBin1, isBin2, zName,
                    zDiffCmd, zBinGlob, fIncludeBinary, pCfg);
      blob_reset(&a);
      blob_reset(&b);
      blob_reset(&delta);
    }
  }
  db_finalize(&q);
  diff_end(pCfg, nErr);
  if( nErr ) fossil_fatal("abort due to prior errors");
}


/*
** COMMAND: patch
**

    patch_create(flags, zOut, stdout);
    fossil_free(zOut);
  }else
  if( strncmp(zCmd, "diff", n)==0 ){
    const char *zDiffCmd = 0;
    const char *zBinGlob = 0;
    int fIncludeBinary = 0;

    char *zIn;
    unsigned flags = 0;
    DiffConfig DCfg;

    if( find_option("tk",0,0)!=0 ){
      db_close(0);
      diff_tk("patch diff", 3);
      return;
    }
    diff_options(&DCfg, zCmd[0]=='g');
    if( find_option("internal","i",0)==0
     && (DCfg.diffFlags & DIFF_HTML)==0
    ){
      zDiffCmd = diff_command_external(zCmd[0]=='g');
    }
    if( find_option("verbose","v",0)!=0 ) DCfg.diffFlags |= DIFF_VERBOSE;
    if( zDiffCmd ){
      zBinGlob = diff_get_binary_glob();
      fIncludeBinary = diff_include_binary_files();
    }
    db_find_and_open_repository(0, 0);
    if( find_option("force","f",0) )    flags |= PATCH_FORCE;
    verify_all_options();
    zIn = patch_find_patch_filename("apply");
    patch_attach(zIn, stdin);
    patch_diff(flags, zDiffCmd, zBinGlob, fIncludeBinary, &DCfg);
    fossil_free(zIn);
  }else
  if( strncmp(zCmd, "pull", n)==0 ){
    FILE *pIn = 0;
    unsigned flags = 0;
    const char *zFossilCmd = find_option("fossilcmd",0,1);
    if( find_option("dryrun","n",0) )   flags |= PATCH_DRYRUN;

  }
  @ <hr />
  @ Baseline: \
  skin_emit_skin_selector("basis", zBasis, zDraft);
  @ <input type="submit" name="diff" value="Unified Diff" />
  @ <input type="submit" name="sbsdiff" value="Side-by-Side Diff" />
  if( P("diff")!=0 || P("sbsdiff")!=0 ){

    Blob from, to, out;
    DiffConfig DCfg;
    construct_diff_flags(1, &DCfg);
    DCfg.diffFlags |= DIFF_STRIP_EOLCR;
    if( P("sbsdiff")!=0 ) DCfg.diffFlags |= DIFF_SIDEBYSIDE;
    blob_init(&to, zContent, -1);
    blob_init(&from, skin_file_content(zBasis, zFile), -1);
    blob_zero(&out);
    DCfg.diffFlags |= DIFF_HTML | DIFF_NOTTOOBIG; 
    if( DCfg.diffFlags & DIFF_SIDEBYSIDE ){
      text_diff(&from, &to, &out, &DCfg);
      @ %s(blob_str(&out))
    }else{
      DCfg.diffFlags |= DIFF_LINENO;
      text_diff(&from, &to, &out, &DCfg);

      @ <pre class="udiff">
      @ %s(blob_str(&out))
      @ </pre>
    }
    blob_reset(&from);
    blob_reset(&to);
    blob_reset(&out);

*/
static void stash_diff(
  int stashid,             /* The stash entry to diff */
  const char *zDiffCmd,    /* Command used for diffing */
  const char *zBinGlob,    /* GLOB pattern to determine binary files */
  int fBaseline,           /* Diff against original baseline check-in if true */
  int fIncludeBinary,      /* Do diffs against binary files */
  DiffConfig *pCfg         /* Diff formatting options */
){
  Stmt q;
  Blob empty;
  int bWebpage = (pCfg->diffFlags & DIFF_WEBPAGE)!=0;
  blob_zero(&empty);
  diff_begin(pCfg);
  db_prepare(&q,
     "SELECT blob.rid, isRemoved, isExec, isLink, origname, newname, delta"
     "  FROM stashfile, blob WHERE stashid=%d AND blob.uuid=stashfile.hash",
     stashid
  );
  while( db_step(&q)==SQLITE_ROW ){
    int rid = db_column_int(&q, 0);
    int isRemoved = db_column_int(&q, 1);
    int isLink = db_column_int(&q, 3);
    int isBin1, isBin2;
    const char *zOrig = db_column_text(&q, 4);
    const char *zNew = db_column_text(&q, 5);
    char *zOPath = mprintf("%s%s", g.zLocalRoot, zOrig);
    Blob a, b;
    if( rid==0 ){
      db_ephemeral_blob(&q, 6, &a);
      if( !bWebpage ) fossil_print("ADDED %s\n", zNew);
      diff_print_index(zNew, pCfg, 0);
      isBin1 = 0;
      isBin2 = fIncludeBinary ? 0 : looks_like_binary(&a);
      diff_file_mem(&empty, &a, isBin1, isBin2, zNew, zDiffCmd,
                    zBinGlob, fIncludeBinary, pCfg);
    }else if( isRemoved ){
      if( !bWebpage) fossil_print("DELETE %s\n", zOrig);
      diff_print_index(zNew, pCfg, 0);
      isBin2 = 0;
      if( fBaseline ){
        content_get(rid, &a);
        isBin1 = fIncludeBinary ? 0 : looks_like_binary(&a);
        diff_file_mem(&a, &empty, isBin1, isBin2, zOrig, zDiffCmd,
                      zBinGlob, fIncludeBinary, pCfg);
      }
    }else{
      Blob delta;
      int isOrigLink = file_islink(zOPath);
      db_ephemeral_blob(&q, 6, &delta);
      if( !bWebpage ) fossil_print("CHANGED %s\n", zNew);
      if( !isOrigLink != !isLink ){
        diff_print_index(zNew, pCfg, 0);
        diff_print_filenames(zOrig, zNew, pCfg, 0);
        printf(DIFF_CANNOT_COMPUTE_SYMLINK);
      }else{
        content_get(rid, &a);
        blob_delta_apply(&a, &delta, &b);
        isBin1 = fIncludeBinary ? 0 : looks_like_binary(&a);
        isBin2 = fIncludeBinary ? 0 : looks_like_binary(&b);
        if( fBaseline ){
          diff_file_mem(&a, &b, isBin1, isBin2, zNew,
                        zDiffCmd, zBinGlob, fIncludeBinary, pCfg);
        }else{
          /*Diff with file on disk using fSwapDiff=1 to show the diff in the
            same direction as if fBaseline=1.*/
          diff_file(&b, isBin2, zOPath, zNew, zDiffCmd,
              zBinGlob, fIncludeBinary, pCfg, 1, 0);
        }
        blob_reset(&a);
        blob_reset(&b);
      }
      blob_reset(&delta);
    }
  }
  db_finalize(&q);
  diff_end(pCfg, 0);
}

/*
** Drop the indicated stash
*/
static void stash_drop(int stashid){
  db_multi_exec(

   || memcmp(zCmd, "cat", nCmd)==0
   || memcmp(zCmd, "gcat", nCmd)==0
  ){
    const char *zDiffCmd = 0;
    const char *zBinGlob = 0;
    int fIncludeBinary = 0;
    int fBaseline = 0;
    DiffConfig DCfg;

    if( strstr(zCmd,"show")!=0 || strstr(zCmd,"cat")!=0 ){
      fBaseline = 1;
    }
    if( find_option("tk",0,0)!=0 ){
      db_close(0);
      diff_tk(fBaseline ? "stash show" : "stash diff", 3);
      return;
    }
    diff_options(&DCfg, zCmd[0]=='g');
    if( find_option("internal","i",0)==0
     && (DCfg.diffFlags & DIFF_HTML)==0
    ){
      zDiffCmd = diff_command_external(zCmd[0]=='g');
    }
    if( find_option("verbose","v",0)!=0 ) DCfg.diffFlags |= DIFF_VERBOSE;
    if( g.argc>4 ) usage(mprintf("%s ?STASHID? ?DIFF-OPTIONS?", zCmd));
    if( zDiffCmd ){
      zBinGlob = diff_get_binary_glob();
      fIncludeBinary = diff_include_binary_files();
    }
    stashid = stash_get_id(g.argc==4 ? g.argv[3] : 0);
    stash_diff(stashid, zDiffCmd, zBinGlob, fBaseline, fIncludeBinary, &DCfg);

  }else
  if( memcmp(zCmd, "help", nCmd)==0 ){
    g.argv[1] = "help";
    g.argv[2] = "stash";
    g.argc = 3;
    help_cmd();
  }else
  {
    usage("SUBCOMMAND ARGS...");
  }
  db_end_transaction(0);
}

*/
void wdiff_page(void){
  const char *zId;
  const char *zPid;
  Manifest *pW1, *pW2 = 0;
  int rid1, rid2, nextRid;
  Blob w1, w2, d;
  DiffConfig DCfg;

  login_check_credentials();
  if( !g.perm.RdWiki ){ login_needed(g.anon.RdWiki); return; }
  zId = P("id");
  if( zId==0 ){
    rid1 = atoi(PD("rid","0"));
  }else{

  nextRid = wiki_next(wiki_tagid(pW1->zWikiTitle),pW1->rDate);
  if( nextRid ){
    style_submenu_element("Next", "%R/wdiff?rid=%d", nextRid);
  }
  style_set_current_feature("wiki");
  style_header("Changes To %s", pW1->zWikiTitle);
  blob_zero(&d);
  construct_diff_flags(1, &DCfg);
  DCfg.diffFlags |= DIFF_HTML | DIFF_LINENO;
  text_diff(&w2, &w1, &d, &DCfg);
  @ <pre class="udiff">
  @ %s(blob_str(&d))
  @ <pre>
  manifest_destroy(pW1);
  manifest_destroy(pW2);
  style_finish_page();
}