**     /zip/[VERSION/]NAME.zip
**     /sqlar/[VERSION/]NAME.sqlar
**
** Generate a ZIP Archive or an SQL Archive for the check-in specified by
** VERSION.  The archive is called NAME.zip or NAME.sqlar and has a top-level
** directory called NAME.
**
** The optional VERSION element defaults to the name of the main branch
** (usually "trunk") per the r= rules below.
** All of the following URLs are equivalent:
**
**      /zip/release/xyz.zip
**      /zip?r=release&name=xyz.zip
**      /zip/xyz.zip?r=release
**      /zip?name=release/xyz.zip
**
** Query parameters:
**
**   name=[CKIN/]NAME    The optional CKIN component of the name= parameter
**                       identifies the check-in from which the archive is
**                       constructed.  If CKIN is omitted and there is no
**                       r= query parameter, then use the name of the main
**                       branch (usually "trunk").  NAME is the
**                       name of the download file.  The top-level directory
**                       in the generated archive is called by NAME with the
**                       file extension removed.
**
**   r=TAG               TAG identifies the check-in that is turned into an
**                       SQL or ZIP archive.  The default value is the name
**                       of the main branch (usually "trunk").
**                       If r= is omitted and if the name= query parameter
**                       contains one "/" character then the of part the
**                       name= value before the / becomes the TAG and the
**                       part of the name= value  after the / is the download
**                       filename.  If no check-in is specified by either
**                       name= or r=, then the name of the main branch
**                       (usually "trunk") is used.
**
**   in=PATTERN          Only include files that match the comma-separate
**                       list of GLOB patterns in PATTERN, as with ex=
**
**   ex=PATTERN          Omit any file that match PATTERN.  PATTERN is a
**                       comma-separated list of GLOB patterns, where each
**                       pattern can optionally be quoted using ".." or '..'.

  const char *zExclude;         /* The ex= query parameter */
  Blob cacheKey;                /* The key to cache */
  Glob *pInclude = 0;           /* The compiled in= glob pattern */
  Glob *pExclude = 0;           /* The compiled ex= glob pattern */
  Blob zip;                     /* ZIP archive accumulated here */
  int eType = ARCHIVE_ZIP;      /* Type of archive to generate */
  char *zType;                  /* Human-readable archive type */
  char *zMainBranch = db_get("main-branch", 0);

  login_check_credentials();
  if( !g.perm.Zip ){ login_needed(g.anon.Zip); return; }
  if( robot_restrict("zip") ) return;
  if( fossil_strcmp(g.zPath, "sqlar")==0 ){
    eType = ARCHIVE_SQLAR;
    zType = "SQL";
  }else{
    eType = ARCHIVE_ZIP;
    zType = "ZIP";
  }
  fossil_nice_default();
  zName = fossil_strdup(PD("name",""));
  z = P("r");
  if( z==0 ) z = P("uuid");
  if( z==0 ) z = tar_uuid_from_name(&zName);
  if( z==0 ) z = fossil_strdup(zMainBranch);
  nName = strlen(zName);
  g.zOpenRevision = zRid = fossil_strdup(z);
  nRid = strlen(zRid);
  zInclude = P("in");
  if( zInclude ) pInclude = glob_create(zInclude);
  zExclude = P("ex");
  if( zExclude ) pExclude = glob_create(zExclude);

  blob_zero(&zip);
  if( cache_read(&zip, zKey)==0 ){
    zip_of_checkin(eType, rid, &zip, zName, pInclude, pExclude, 0);
    cache_write(&zip, zKey);
  }
  glob_free(pInclude);
  glob_free(pExclude);
  fossil_free(zMainBranch);
  fossil_free(zName);
  fossil_free(zRid);
  g.zOpenRevision = 0;
  blob_reset(&cacheKey);
  cgi_set_content(&zip);
  if( eType==ARCHIVE_ZIP ){
    cgi_set_content_type("application/zip");
  }else{
    cgi_set_content_type("application/sqlar");
  }
}