** Trailing whitespace is removed from each line.  2010-08-20:  Not any
** more.  If trailing whitespace is ignored, the "patch" command gets
** confused by the diff output.  Ticket [a9f7b23c2e376af5b0e5b]
**
** Return 0 if the file is binary or contains a line that is
** too long.
*/
static DLine *break_into_lines(const char *z, int n, int *pnLine, int ignoreWS){
  int nLine, i, j, k, x;
  unsigned int h, h2;
  DLine *a;

  /* Count the number of lines.  Allocate space to hold
  ** the returned array.
  */

  if( a==0 ) fossil_panic("out of memory");
  memset(a, 0, nLine*sizeof(a[0]) );

  /* Fill in the array */
  for(i=0; i<nLine; i++){
    a[i].z = z;
    for(j=0; z[j] && z[j]!='\n'; j++){}
    k = j;
    while( ignoreWS && k>0 && isspace(z[k-1]) ){ k--; }
    for(h=0, x=0; x<k; x++){
      h = h ^ (h<<2) ^ z[x];
    }
    a[i].h = h = (h<<LENGTH_MASK_SZ) | k;;
    h2 = h % nLine;
    a[i].iNext = a[h2].iHash;
    a[h2].iHash = i+1;

** 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 unified diff here if not NULL */
  int nContext,    /* Amount of context to unified diff */
  int ignoreEolWs  /* Ignore whitespace at the end of lines */
){
  DContext c;
 
  /* Prepare the input files */
  memset(&c, 0, sizeof(c));
  c.aFrom = break_into_lines(blob_str(pA_Blob), blob_size(pA_Blob),
                             &c.nFrom, ignoreEolWs);
  c.aTo = break_into_lines(blob_str(pB_Blob), blob_size(pB_Blob),
                           &c.nTo, ignoreEolWs);
  if( c.aFrom==0 || c.aTo==0 ){
    free(c.aFrom);
    free(c.aTo);
    if( pOut ){
      blob_appendf(pOut, "cannot compute difference between binary files\n");
    }
    return 0;

  int i;
  int *R;
  if( g.argc<4 ) usage("FILE1 FILE2 ...");
  blob_read_from_file(&a, g.argv[2]);
  for(i=3; i<g.argc; i++){
    if( i>3 ) printf("-------------------------------\n");
    blob_read_from_file(&b, g.argv[i]);
    R = text_diff(&a, &b, 0, 0, 0);
    for(r=0; R[r] || R[r+1] || R[r+2]; r += 3){
      printf(" copy %4d  delete %4d  insert %4d\n", R[r], R[r+1], R[r+2]);
    }
    /* free(R); */
    blob_reset(&b);
  }
}

/*
** COMMAND: test-udiff
*/
void test_udiff_cmd(void){
  Blob a, b, out;
  if( g.argc!=4 ) usage("FILE1 FILE2");
  blob_read_from_file(&a, g.argv[2]);
  blob_read_from_file(&b, g.argv[3]);
  blob_zero(&out);
  text_diff(&a, &b, &out, 3, 0);
  blob_write_to_file(&out, "-");
}

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

** to be annotated.  The annotator takes control of the input Blob and
** will release it when it is finished with it.
*/
static int annotation_start(Annotator *p, Blob *pInput){
  int i;

  memset(p, 0, sizeof(*p));
  p->c.aTo = break_into_lines(blob_str(pInput), blob_size(pInput),&p->c.nTo,1);
  if( p->c.aTo==0 ){
    return 1;
  }
  p->aOrig = malloc( sizeof(p->aOrig[0])*p->c.nTo );
  if( p->aOrig==0 ) fossil_panic("out of memory");
  for(i=0; i<p->c.nTo; i++){
    p->aOrig[i].z = p->c.aTo[i].z;

*/
static int annotation_step(Annotator *p, Blob *pParent, char *zPName){
  int i, j;
  int lnTo;

  /* Prepare the parent file to be diffed */
  p->c.aFrom = break_into_lines(blob_str(pParent), blob_size(pParent),
                                &p->c.nFrom, 1);
  if( p->c.aFrom==0 ){
    return 1;
  }

  /* Compute the differences going from pParent to the file being
  ** annotated. */
  diff_all(&p->c);

** Use the internal diff logic if zDiffCmd is NULL.  Otherwise call the
** command zDiffCmd to do the diffing.
*/
static void diff_file(
  Blob *pFile1,             /* In memory content to compare from */
  const char *zFile2,       /* On disk content to compare to */
  const char *zName,        /* Display name of the file */
  const char *zDiffCmd,     /* Command for comparison */
  int ignoreEolWs           /* Ignore whitespace at end of lines */
){
  if( zDiffCmd==0 ){
    Blob out;      /* Diff output text */
    Blob file2;    /* Content of zFile2 */

    /* Read content of zFile2 into memory */
    blob_zero(&file2);
    blob_read_from_file(&file2, zFile2);

    /* Compute and output the differences */
    blob_zero(&out);
    text_diff(pFile1, &file2, &out, 5, ignoreEolWs);
    printf("--- %s\n+++ %s\n", zName, zName);
    printf("%s\n", blob_str(&out));

    /* Release memory resources */
    blob_reset(&file2);
    blob_reset(&out);
  }else{

** Use the internal diff logic if zDiffCmd is NULL.  Otherwise call the
** command zDiffCmd to do the diffing.
*/
static void diff_file_mem(
  Blob *pFile1,             /* In memory content to compare from */
  Blob *pFile2,             /* In memory content to compare to */
  const char *zName,        /* Display name of the file */
  const char *zDiffCmd,     /* Command for comparison */
  int ignoreEolWs           /* Ignore whitespace at end of lines */
){
  if( zDiffCmd==0 ){
    Blob out;      /* Diff output text */

    blob_zero(&out);
    text_diff(pFile1, pFile2, &out, 5, ignoreEolWs);
    printf("--- %s\n+++ %s\n", zName, zName);
    printf("%s\n", blob_str(&out));

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

  }
}

/*
** Do a diff against a single file named in g.argv[2] from version zFrom
** against the same file on disk.
*/
static void diff_one_against_disk(
  const char *zFrom,        /* Name of file */
  const char *zDiffCmd,     /* Use this "diff" command */
  int ignoreEolWs           /* Ignore whitespace changes at end of lines */
){
  Blob fname;
  Blob content;
  file_tree_name(g.argv[2], &fname, 1);
  historical_version_of_file(zFrom, blob_str(&fname), &content, 0);
  diff_file(&content, g.argv[2], g.argv[2], zDiffCmd, ignoreEolWs);
  blob_reset(&content);
  blob_reset(&fname);
}

/*
** Run a diff between the version zFrom and files on disk.  zFrom might
** be NULL which means to simply show the difference between the edited
** files on disk and the check-out on which they are based.
*/
static void diff_all_against_disk(
  const char *zFrom,        /* Version to difference from */
  const char *zDiffCmd,     /* Use this diff command.  NULL for built-in */
  int ignoreEolWs           /* Ignore end-of-line whitespace */
){
  int vid;
  Blob sql;
  Stmt q;

  vid = db_lget_int("checkout", 0);
  vfile_check_signature(vid, 1);
  blob_zero(&sql);

      int srcid = db_column_int(&q, 4);
      Blob content;
      content_get(srcid, &content);
      printf("Index: %s\n======================================="
             "============================\n",
             zPathname
      );
      diff_file(&content, zFullName, zPathname, zDiffCmd, ignoreEolWs);
      blob_reset(&content);
    }
    free(zFullName);
  }
  db_finalize(&q);
  db_end_transaction(1);  /* ROLLBACK */
}

/*
** Output the differences between two versions of a single file.
** zFrom and zTo are the check-ins containing the two file versions.
** The filename is contained in g.argv[2].
*/
static void diff_one_two_versions(
  const char *zFrom,
  const char *zTo,
  const char *zDiffCmd,
  int ignoreEolWs
){
  char *zName;
  Blob fname;
  Blob v1, v2;
  file_tree_name(g.argv[2], &fname, 1);
  zName = blob_str(&fname);
  historical_version_of_file(zFrom, zName, &v1, 0);
  historical_version_of_file(zTo, zName, &v2, 0);
  diff_file_mem(&v1, &v2, zName, zDiffCmd, ignoreEolWs);
  blob_reset(&v1);
  blob_reset(&v2);
  blob_reset(&fname);
}

/*
** Output the differences between two check-ins.
*/
static void diff_all_two_versions(
  const char *zFrom,
  const char *zTo,
  const char *zDiffCmd,
  int ignoreEolWs
){
  Manifest mFrom, mTo;
  int iFrom, iTo;

  manifest_from_name(zFrom, &mFrom);
  manifest_from_name(zTo, &mTo);
  iFrom = iTo = 0;

      /* No changes */
      iFrom++;
      iTo++;
    }else{
      Blob f1, f2;
      int rid;
      printf("CHANGED %s\n", mFrom.aFile[iFrom].zName);
      printf("Index: %s\n======================================="
             "============================\n",
             mFrom.aFile[iFrom].zName
      );
      rid = uuid_to_rid(mFrom.aFile[iFrom].zUuid, 0);
      content_get(rid, &f1);
      rid = uuid_to_rid(mTo.aFile[iTo].zUuid, 0);
      content_get(rid, &f2);
      diff_file_mem(&f1, &f2, mFrom.aFile[iFrom].zName, zDiffCmd, ignoreEolWs);
      blob_reset(&f1);
      blob_reset(&f2);
      iFrom++;
      iTo++;
    }
  }
  manifest_clear(&mFrom);

  if( zTo==0 ){
    db_must_be_within_tree();
    verify_all_options();
    if( !isInternDiff && g.argc==3 ){
      zDiffCmd = db_get(isGDiff ? "gdiff-command" : "diff-command", 0);
    }
    if( g.argc==3 ){
      diff_one_against_disk(zFrom, zDiffCmd, 0);
    }else{
      diff_all_against_disk(zFrom, zDiffCmd, 0);
    }
  }else if( zFrom==0 ){
    fossil_fatal("must use --from if --to is present");
  }else{
    db_find_and_open_repository(1);
    verify_all_options();
    if( !isInternDiff ){
      zDiffCmd = db_get(isGDiff ? "gdiff-command" : "diff-command", 0);
    }
    if( g.argc==3 ){
      diff_one_two_versions(zFrom, zTo, zDiffCmd, 0);
    }else{
      diff_all_two_versions(zFrom, zTo, zDiffCmd, 0);
    }
  }
}

** Append the difference between two RIDs to the output
*/
static void append_diff(int fromid, int toid){
  Blob from, to, out;
  content_get(fromid, &from);
  content_get(toid, &to);
  blob_zero(&out);
  text_diff(&from, &to, &out, 5, 1);
  @ %h(blob_str(&out))
  blob_reset(&from);
  blob_reset(&to);
  blob_reset(&out);  
}

/*

  object_description(v2, 1, 0);
  @ </blockquote>
  @ <hr>
  @ <blockquote><pre>
  content_get(v1, &c1);
  content_get(v2, &c2);
  blob_zero(&diff);
  text_diff(&c1, &c2, &diff, 4, 1);
  blob_reset(&c1);
  blob_reset(&c2);
  @ %h(blob_str(&diff))
  @ </pre></blockquote>
  blob_reset(&diff);
  style_footer();
}

  ** 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.
  */
  aC1 = text_diff(pPivot, pV1, 0, 0, 1);
  aC2 = text_diff(pPivot, pV2, 0, 0, 1);
  if( aC1==0 || aC2==0 ){
    free(aC1);
    free(aC2);
    return -1;
  }

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

    content_get(rid2, &content2);
    manifest_parse(&m2, &content2);
    if( m2.type==CFTYPE_WIKI ){
      blob_init(&w2, m2.zWiki, -1);
    }
  }
  blob_zero(&d);
  text_diff(&w2, &w1, &d, 5, 1);
  @ <pre>
  @ %h(blob_str(&d))
  @ </pre>
  style_footer();
}

/*