**
** pOut must be either uninitialized or the same as pIn.
*/
int blob_uncompress(Blob *pIn, Blob *pOut){
  unsigned int nOut;
  unsigned char *inBuf;
  unsigned int nIn = blob_size(pIn);
  Blob temp = empty_blob;
  int rc;
  unsigned long int nOut2;
  if( nIn<=4 ){
    return 0;
  }
  inBuf = (unsigned char*)blob_buffer(pIn);
  nOut = (inBuf[0]<<24) + (inBuf[1]<<16) + (inBuf[2]<<8) + inBuf[3];

                             contentCache.nAlloc*sizeof(contentCache.a[0]));
  }
  p = &contentCache.a[contentCache.n++];
  p->rid = rid;
  p->age = contentCache.nextAge++;
  contentCache.szTotal += blob_size(pBlob);
  p->content = *pBlob;
  *pBlob = empty_blob;
  bag_insert(&contentCache.inCache, rid);
}

/*
** Clear the content cache.
*/
void content_clear_cache(void){

  if( nextRid==0 ){
    rc = content_of_blob(rid, pBlob);
  }else{
    int n = 1;
    int nAlloc = 10;
    int *a = 0;
    int mx;
    Blob delta = empty_blob, next = empty_blob;

    a = fossil_malloc( sizeof(a[0])*nAlloc );
    a[0] = rid;
    a[1] = nextRid;
    n = 1;
    while( !bag_find(&contentCache.inCache, nextRid)
        && (nextRid = findSrcid(nextRid))>0 ){

** Prepare a Stmt.  Assume that the Stmt is previously uninitialized.
** If the input string contains multiple SQL statements, only the first
** one is processed.  All statements beyond the first are silently ignored.
*/
int db_vprepare(Stmt *pStmt, int errOk, const char *zFormat, va_list ap){
  int rc;
  char *zSql;
  pStmt->sql = empty_blob;
  blob_vappendf(&pStmt->sql, zFormat, ap);
  va_end(ap);
  zSql = blob_str(&pStmt->sql);
  nPrepare++;
  rc = sqlite3_prepare_v2(g.db, zSql, -1, &pStmt->pStmt, 0);
  if( rc!=0 && !errOk ){
    db_err("%s\n%s", sqlite3_errmsg(g.db), zSql);

**
** It works ok for pTarget and pOriginal to be the same blob.
**
** Return the length of the target.  Return -1 if there is an error.
*/
int blob_delta_apply(Blob *pOriginal, Blob *pDelta, Blob *pTarget){
  int len, n;
  Blob out = empty_blob;

  n = delta_output_size(blob_buffer(pDelta), blob_size(pDelta));
  blob_zero(&out);
  if( n<0 ) return -1;
  blob_resize(&out, n);
  len = delta_apply(
     blob_buffer(pOriginal), blob_size(pOriginal),

}

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

/*
** Linked list of strings, labels used in the annotator code.
** The elements of the list and the pointed string (str)
** will be freed once they become totally unreferenced
** (nref == 0).
*/
struct Label
{
    struct Label *prev;   /* previous element */
    struct Label *next;   /* next element */
    char *str;            /* The label string */
    int nref;             /* Number of references to the string */
};

/*
** The status of an annotation operation is recorded by an instance
** of the following structure.
*/
typedef struct Annotator Annotator;
struct Annotator {
  DContext c;       /* The diff-engine context */
  struct AnnLine {  /* Lines of the original files... */
    const char *z;       /* The text of the line */
    short int n;         /* Number of bytes (omitting trailing space and \n) */
    short int iLevel;    /* Level at which tag was set */
    struct Label *zSrc;    /* Tag showing origin of this line */
  } *aOrig;
  int nOrig;        /* Number of elements in aOrig[] */
  int nNoSrc;       /* Number of entries where aOrig[].zSrc==NULL */
  int iLevel;       /* Current level */
  int nVers;        /* Number of versions analyzed */
  struct Label **azVers;    /* Names of versions analyzed */
  Blob toAnnotate;
  struct Label *firstLabel;
};

/*
** Initialize the annotation process by specifying the file that is
** 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){
  int i;


  p->c.aTo = break_into_lines(blob_str(&p->toAnnotate),
          blob_size(&p->toAnnotate),&p->c.nTo,1);
  if( p->c.aTo==0 ){
    return 1;
  }
  p->aOrig = fossil_malloc( sizeof(p->aOrig[0])*p->c.nTo );
  for(i=0; i<p->c.nTo; i++){
    p->aOrig[i].z = p->c.aTo[i].z;
    p->aOrig[i].n = p->c.aTo[i].h & LENGTH_MASK;
    p->aOrig[i].zSrc = 0;
  }
  p->nOrig = p->c.nTo;
  return 0;
}

/*
** The input pParent is the next most recent ancestor of the file
** being annotated.  Do another step of the annotation.  Return true
** if additional annotation is required.  zPName is the tag to insert
** on each line of the file being annotated that was contributed by
** pParent.  Memory to hold zPName is leaked.
*/
static int annotation_step(Annotator *p, Blob *pParent, struct Label *zPName){
  int i, j;
  int lnTo;
  int iPrevLevel;
  int iThisLevel;

  /* 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 ){
    free(p->c.aFrom);
    return 1;
  }

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

  /* Where new lines are inserted on this difference, record the
  ** zPName as the source of the new line.
  */
  iPrevLevel = p->iLevel;
  p->iLevel++;
  iThisLevel = p->iLevel;
  for(i=lnTo=0; i<p->c.nEdit; i+=3){
    struct AnnLine *x = &p->aOrig[lnTo];
    for(j=0; j<p->c.aEdit[i]; j++, lnTo++, x++){
      if( x->zSrc==0 || x->iLevel==iPrevLevel ){
         if (x->zSrc!=0)
         {
           if(--x->zSrc->nref == 0)
           {
             free(x->zSrc->str);
             if (x->zSrc->prev)
               x->zSrc->prev->next = x->zSrc->next;
             if (x->zSrc->next)
               x->zSrc->next->prev = x->zSrc->prev;
             free(x->zSrc);
           }
         }
         x->zSrc = zPName;
         ++zPName->nref;
         x->iLevel = iThisLevel;
      }
    }
    lnTo += p->c.aEdit[i+2];
  }

  /* Clear out the diff results */
  free(p->c.aEdit);
  p->c.aEdit = 0;
  p->c.nEdit = 0;
  p->c.nEditAlloc = 0;

  /* Clear out the from file */
  free(p->c.aFrom);    
  blob_reset(pParent);

  /* Return no errors */
  return 0;
}


/*
** COMMAND: test-annotate-step
*/
void test_annotate_step_cmd(void){
  Blob b = empty_blob;
  Annotator x;
  int i;

  if( g.argc<4 ) usage("RID1 RID2 ...");
  db_must_be_within_tree();
  memset(&x, 0, sizeof(x));
  x.toAnnotate = empty_blob;
  content_get(name_to_rid(g.argv[2]), &x.toAnnotate);
  if( annotation_start(&x) ){
    fossil_fatal("binary file");
  }
  for(i=3; i<g.argc; i++){
    struct Label *l;
    blob_zero(&b);
    content_get(name_to_rid(g.argv[i]), &b);
    l = fossil_malloc(sizeof(*l));
    l->str = g.argv[i-1];
    l->nref = 0;
    l->next = x.firstLabel;
    if (x.firstLabel)
      x.firstLabel->prev = l;
    x.firstLabel = l;
    if( annotation_step(&x, &b, l) ){
      fossil_fatal("binary file");
    }
  }
  for(i=0; i<x.nOrig; i++){
    const char *zSrc = x.aOrig[i].zSrc->str;
    if( zSrc==0 ) zSrc = g.argv[g.argc-1];
    fossil_print("%10s: %.*s\n", zSrc, x.aOrig[i].n, x.aOrig[i].z);
  }
  while(x.firstLabel) {
    struct Label *l;
    l = x.firstLabel->next;
    assert(x.firstLabel->nref > 0);
    free(x.firstLabel->str);
    free(x.firstLabel);
    x.firstLabel = l;
  }
}

/* Annotation flags */
#define ANN_FILE_VERS  0x001  /* Show file version rather than commit version */

/*
** Compute a complete annotation on a file.  The file is identified
** by its filename number (filename.fnid) and the baseline in which
** it was checked in (mlink.mid).
*/
static void annotate_file(
  Annotator *p,        /* The annotator */
  int fnid,            /* The name of the file to be annotated */
  int mid,             /* Use the version of the file in this check-in */
  int webLabel,        /* Use web-style annotations if true */
  int iLimit,          /* Limit the number of levels if greater than zero */
  int annFlags         /* Flags to alter the annotation */
){

  Blob step = empty_blob;           /* Text of previous revision */
  int rid;             /* Artifact ID of the file being annotated */

  Stmt q;              /* Query returning all ancestor versions */

  /* Initialize the annotation */
  rid = db_int(0, "SELECT fid FROM mlink WHERE mid=%d AND fnid=%d",mid,fnid);
  if( rid==0 ){
    fossil_panic("file #%d is unchanged in manifest #%d", fnid, mid);
  }
  memset(p, 0, sizeof(*p));
  p->toAnnotate = empty_blob;
  if( !content_get(rid, &p->toAnnotate) ){
    fossil_panic("unable to retrieve content of artifact #%d", rid);
  }
  db_multi_exec("CREATE TEMP TABLE ok(rid INTEGER PRIMARY KEY)");
  if( iLimit<=0 ) iLimit = 1000000000;
  compute_direct_ancestors(mid, iLimit);
  annotation_start(p);

  db_prepare(&q, 
    "SELECT mlink.fid,"
    "       (SELECT uuid FROM blob WHERE rid=mlink.%s),"
    "       date(event.mtime), "
    "       coalesce(event.euser,event.user) "
    "  FROM ancestor, mlink, event"

    iLimit>0 ? iLimit : 10000000
  );
  while( db_step(&q)==SQLITE_ROW ){
    int pid = db_column_int(&q, 0);
    const char *zUuid = db_column_text(&q, 1);
    const char *zDate = db_column_text(&q, 2);
    const char *zUser = db_column_text(&q, 3);
    struct Label *l = fossil_malloc(sizeof(*l));
    l->nref = 0;
    l->next = p->firstLabel;
    l->prev = 0;
    if (p->firstLabel)
      p->firstLabel->prev = l;
    if( webLabel ){
      l->str = mprintf(
          "<a href='%s/info/%s' target='infowindow'>%.10s</a> %s %9.9s", 
          g.zTop, zUuid, zUuid, zDate, zUser
      );
    }else{
      l->str = mprintf("%.10s %s %9.9s", zUuid, zDate, zUser);
    }
    p->firstLabel = l;
    p->nVers++;
    p->azVers = fossil_realloc(p->azVers, p->nVers*sizeof(p->azVers[0]) );
    p->azVers[p->nVers-1] = l;
    content_get(pid, &step);
    annotation_step(p, &step, l);
    if (l->nref == 0)
    {
      free(l->str);
      p->firstLabel = l->next;
      if (l->next)
        l->next->prev = 0;
      free(l);
    }
    blob_reset(&step);
  }
  db_finalize(&q);
  free(p->c.aTo);
}

/*
** WEBPAGE: annotate
**
** Query parameters:
**

  if( P("filevers") ) annFlags |= ANN_FILE_VERS;
  annotate_file(&ann, fnid, mid, g.okHistory, iLimit, annFlags);
  if( P("log") ){
    int i;
    @ <h2>Versions analyzed:</h2>
    @ <ol>
    for(i=0; i<ann.nVers; i++){
      @ <li><tt>%s(ann.azVers[i]->str)</tt></li>
    }
    @ </ol>
    @ <hr>
    @ <h2>Annotation:</h2>
  }
  @ <pre>
  for(i=0; i<ann.nOrig; i++){
    ((char*)ann.aOrig[i].z)[ann.aOrig[i].n] = 0;
    @ %s(ann.aOrig[i].zSrc->str): %h(ann.aOrig[i].z)
  }
  @ </pre>
  style_footer();

  free(ann.azVers);
  free(ann.aOrig);
  blob_reset(&ann.toAnnotate);
  while(ann.firstLabel) {
    struct Label *l;
    l = ann.firstLabel->next;
    assert(ann.firstLabel->nref > 0);
    free(ann.firstLabel->str);
    free(ann.firstLabel);
    ann.firstLabel = l;
  }
}

/*
** COMMAND: annotate
**
** %fossil annotate FILENAME
**
** Output the text of a file with markings to show when each line of
** the file was last modified.
**
** Options:
**   --limit N       Only look backwards in time by N versions
**   --log           List all versions analyzed
**   --filevers      Show file version numbers rather than check-in versions
*/
void annotate_cmd(void){
  int fnid;         /* Filename ID */
  int fid;          /* File instance ID */
  int mid;          /* Manifest where file was checked in */
  Blob treename = empty_blob;    /* FILENAME translated to canonical form */
  char *zFilename;  /* Cannonical filename */
  Annotator ann;    /* The annotation of the file */
  int i;            /* Loop counter */
  const char *zLimit; /* The value to the --limit option */
  int iLimit;       /* How far back in time to look */
  int showLog;      /* True to show the log */
  int fileVers;     /* Show file version instead of check-in versions */

  if( fnid==0 ){
    fossil_fatal("no such file: %s", zFilename);
  }
  fid = db_int(0, "SELECT rid FROM vfile WHERE pathname=%Q", zFilename);
  if( fid==0 ){
    fossil_fatal("not part of current checkout: %s", zFilename);
  }
  blob_reset(&treename);
  mid = db_int(0, "SELECT mid FROM mlink WHERE fid=%d AND fnid=%d", fid, fnid);
  if( mid==0 ){
    fossil_panic("unable to find manifest");
  }
  if( fileVers ) annFlags |= ANN_FILE_VERS;
  annotate_file(&ann, fnid, mid, 0, iLimit, annFlags);
  if( showLog ){
    for(i=0; i<ann.nVers; i++){
      printf("version %3d: %s\n", i+1, ann.azVers[i]->str);
    }
    printf("---------------------------------------------------\n");
  }
  for(i=0; i<ann.nOrig; i++){
    fossil_print("%s: %.*s\n", 
                 ann.aOrig[i].zSrc->str, ann.aOrig[i].n, ann.aOrig[i].z);
  }
  free(ann.azVers);
  free(ann.aOrig);
  blob_reset(&ann.toAnnotate);
  while(ann.firstLabel) {
    struct Label *l;
    l = ann.firstLabel->next;
    assert(ann.firstLabel->nref > 0);
    free(ann.firstLabel->str);
    free(ann.firstLabel);
    ann.firstLabel = l;
  }
}

** message and quit if the errFatal flag is true.  If errFatal is
** false, then simply return 0.
**
** The root of the tree is defined by the g.zLocalRoot variable.
*/
int file_tree_name(const char *zOrigName, Blob *pOut, int errFatal){
  int n;
  Blob full = empty_blob;
  int nFull;
  char *zFull;

  blob_zero(pOut);
  db_must_be_within_tree();
  file_canonical_name(zOrigName, &full);
  n = strlen(g.zLocalRoot);