SQLite

struct JsonParse {
  u32 nNode;         /* Number of slots of aNode[] used */
  u32 nAlloc;        /* Number of slots of aNode[] allocated */
  JsonNode *aNode;   /* Array of nodes containing the parse */
  const char *zJson; /* Original JSON string */
  u32 *aUp;          /* Index of parent of each node */
  u8 oom;            /* Set to true if out of memory */
  u8 nErr;           /* Number of errors seen */
};

/**************************************************************************
** Utility routines for dealing with JsonString objects
**************************************************************************/

/* Set the JsonString object to an empty string

    return SQLITE_NOMEM;
  }
  jsonParseFillInParentage(pParse, 0, 0);
  return SQLITE_OK;
}

/* forward declaration */
static JsonNode *jsonLookupAppend(JsonParse*,const char*,int*,const char**);

/*
** Search along zPath to find the node specified.  Return a pointer
** to that node, or NULL if zPath is malformed or if there is no such
** node.
**
** If pApnd!=0, then try to append new nodes to complete zPath if it is
** possible to do so and if no existing node corresponds to zPath.  If
** new nodes are appended *pApnd is set to 1.
*/
static JsonNode *jsonLookupStep(
  JsonParse *pParse,      /* The JSON to search */
  u32 iRoot,              /* Begin the search at this node */
  const char *zPath,      /* The path to search */
  int *pApnd,             /* Append nodes to complete path if not NULL */
  const char **pzErr      /* Make *pzErr point to any syntax error in zPath */
){
  u32 i, j, nKey;
  const char *zKey;
  JsonNode *pRoot = &pParse->aNode[iRoot];
  if( zPath[0]==0 ) return pRoot;
  if( zPath[0]=='.' ){
    if( pRoot->eType!=JSON_OBJECT ) return 0;
    zPath++;
    if( zPath[0]=='"' ){
      zKey = zPath + 1;
      for(i=1; zPath[i] && zPath[i]!='"'; i++){}
      nKey = i-1;
      if( zPath[i] ) i++;
    }else{
      zKey = zPath;
      for(i=0; zPath[i] && zPath[i]!='.' && zPath[i]!='['; i++){}
      nKey = i;
    }
    if( nKey==0 ){
      *pzErr = zPath;
      return 0;
    }
    j = 1;
    for(;;){
      while( j<=pRoot->n ){
        if( pRoot[j].n==nKey+2
         && strncmp(&pRoot[j].u.zJContent[1],zKey,nKey)==0
        ){
          return jsonLookupStep(pParse, iRoot+j+1, &zPath[i], pApnd, pzErr);
        }
        j++;
        j += jsonNodeSize(&pRoot[j]);
      }
      if( (pRoot->jnFlags & JNODE_APPEND)==0 ) break;
      iRoot += pRoot->u.iAppend;
      pRoot = &pParse->aNode[iRoot];
      j = 1;
    }
    if( pApnd ){
      u32 iStart, iLabel;
      JsonNode *pNode;
      iStart = jsonParseAddNode(pParse, JSON_OBJECT, 2, 0);
      iLabel = jsonParseAddNode(pParse, JSON_STRING, i, zPath);
      zPath += i;
      pNode = jsonLookupAppend(pParse, zPath, pApnd, pzErr);
      if( pParse->oom ) return 0;
      if( pNode ){
        pRoot = &pParse->aNode[iRoot];
        pRoot->u.iAppend = iStart - iRoot;
        pRoot->jnFlags |= JNODE_APPEND;
        pParse->aNode[iLabel].jnFlags |= JNODE_RAW;
      }
      return pNode;
    }
  }else if( zPath[0]=='[' && isdigit(zPath[1]) ){
    if( pRoot->eType!=JSON_ARRAY ) return 0;
    i = 0;
    zPath++;
    while( isdigit(zPath[0]) ){
      i = i*10 + zPath[0] - '0';
      zPath++;
    }
    if( zPath[0]!=']' ){
      *pzErr = zPath;
      return 0;
    }
    zPath++;
    j = 1;
    for(;;){
      while( j<=pRoot->n && (i>0 || (pRoot[j].jnFlags & JNODE_REMOVE)!=0) ){
        if( (pRoot[j].jnFlags & JNODE_REMOVE)==0 ) i--;
        j += jsonNodeSize(&pRoot[j]);
      }
      if( (pRoot->jnFlags & JNODE_APPEND)==0 ) break;
      iRoot += pRoot->u.iAppend;
      pRoot = &pParse->aNode[iRoot];
      j = 1;
    }
    if( j<=pRoot->n ){
      return jsonLookupStep(pParse, iRoot+j, zPath, pApnd, pzErr);
    }
    if( i==0 && pApnd ){
      u32 iStart;
      JsonNode *pNode;
      iStart = jsonParseAddNode(pParse, JSON_ARRAY, 1, 0);
      pNode = jsonLookupAppend(pParse, zPath, pApnd, pzErr);
      if( pParse->oom ) return 0;
      if( pNode ){
        pRoot = &pParse->aNode[iRoot];
        pRoot->u.iAppend = iStart - iRoot;
        pRoot->jnFlags |= JNODE_APPEND;
      }
      return pNode;
    }
  }else if( zPath[0]!=0 ){
    *pzErr = zPath;
  }
  return 0;
}

/*
** Append content to pParse that will complete zPath.  Return a pointer
** to the inserted node, or return NULL if the append fails.
*/
static JsonNode *jsonLookupAppend(
  JsonParse *pParse,     /* Append content to the JSON parse */
  const char *zPath,     /* Description of content to append */
  int *pApnd,            /* Set this flag to 1 */
  const char **pzErr     /* Make this point to any syntax error */
){
  *pApnd = 1;
  if( zPath[0]==0 ){
    jsonParseAddNode(pParse, JSON_NULL, 0, 0);
    return pParse->oom ? 0 : &pParse->aNode[pParse->nNode-1];
  }
  if( zPath[0]=='.' ){
    jsonParseAddNode(pParse, JSON_OBJECT, 0, 0);
  }else if( strncmp(zPath,"[0]",3)==0 ){
    jsonParseAddNode(pParse, JSON_ARRAY, 0, 0);
  }else{
    return 0;
  }
  if( pParse->oom ) return 0;
  return jsonLookupStep(pParse, pParse->nNode-1, zPath, pApnd, pzErr);
}

/*
** Return the text of a syntax error message on a JSON path.  Space is
** obtained from sqlite3_malloc().
*/
static char *jsonPathSyntaxError(const char *zErr){
  return sqlite3_mprintf("JSON path error near '%q'", zErr);
}

/*
** Do a node lookup using zPath.  Return a pointer to the node on success.
** Return NULL if not found or if there is an error.
**
** On an error, write an error message into pCtx and increment the
** pParse->nErr counter.
**
** If pApnd!=NULL then try to append missing nodes and set *pApnd = 1 if
** nodes are appended.
**
** If the path starts with $$ then set *pFlags to JNODE_REPLACE|JNODE_JSON
** as a single to the caller that the input text to be inserted should be 
** interpreted as JSON rather than as ordinary text.
*/
static JsonNode *jsonLookup(
  JsonParse *pParse,      /* The JSON to search */
  const char *zPath,      /* The path to search */
  int *pApnd,             /* Append nodes to complete path if not NULL */
  sqlite3_context *pCtx,  /* Report errors here, if not NULL */
  u8 *pFlags              /* Write JNODE_REPLACE or _REPLACE|_JSON here */
){
  const char *zErr = 0;
  JsonNode *pNode = 0;
  u8 fg = JNODE_REPLACE;

  if( zPath==0 ) return 0;
  if( zPath[0]!='$' ){
    zErr = zPath;
    goto lookup_err;
  }
  zPath++;
  if( zPath[0]=='$' ){
    if( pFlags==0 ){
      zErr = zPath;
      goto lookup_err;
    }
    zPath++;
    fg = JNODE_REPLACE|JNODE_JSON;
  }
  if( pFlags ) *pFlags = fg;
  pNode = jsonLookupStep(pParse, 0, zPath, pApnd, &zErr);
  return pNode;

lookup_err:
  pParse->nErr++;
  if( zErr!=0 && pCtx!=0 ){
    char *z = jsonPathSyntaxError(zErr);
    if( z ){
      sqlite3_result_error(pCtx, z, -1);
      sqlite3_free(z);
    }else{
      sqlite3_result_error_nomem(pCtx);
    }
  }
  if( pFlags ) *pFlags = fg;
  return 0;
}


/*
** Report the wrong number of arguments for json_insert(), json_replace()
** or json_set().
*/
static void jsonWrongNumArgs(
  sqlite3_context *pCtx,
  const char *zFuncName
){
  char *zMsg = sqlite3_mprintf("json_%s() needs an odd number of arguments",
                               zFuncName);
  sqlite3_result_error(pCtx, zMsg, -1);
  sqlite3_free(zMsg);     
}


/****************************************************************************
** SQL functions used for testing and debugging
****************************************************************************/

#ifdef SQLITE_DEBUG
/*

  sqlite3_context *ctx,
  int argc,
  sqlite3_value **argv
){
  JsonParse x;          /* The parse */
  sqlite3_int64 n = 0;
  u32 i;


  if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
  if( x.nNode ){
    JsonNode *pNode;
    if( argc==2 ){
      const char *zPath = (const char*)sqlite3_value_text(argv[1]);


      pNode = jsonLookup(&x, zPath, 0, ctx, 0);
    }else{
      pNode = x.aNode;
    }

    if( pNode==0 ){
      x.nErr = 1;

    }else if( pNode->eType==JSON_ARRAY ){
      assert( (pNode->jnFlags & JNODE_APPEND)==0 );
      for(i=1; i<=pNode->n; n++){
        i += jsonNodeSize(&pNode[i]);
      }
    }
  }
  if( x.nErr==0 ) sqlite3_result_int64(ctx, n);
  jsonParseReset(&x);

}

/*
** json_extract(JSON, PATH)
**
** Return the element described by PATH.  Return NULL if JSON is not
** valid JSON or if there is no PATH element or if PATH is malformed.
*/
static void jsonExtractFunc(
  sqlite3_context *ctx,
  int argc,
  sqlite3_value **argv
){
  JsonParse x;          /* The parse */
  JsonNode *pNode;
  const char *zPath;
  assert( argc==2 );
  zPath = (const char*)sqlite3_value_text(argv[1]);



  if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
  pNode = jsonLookup(&x, zPath, 0, ctx, 0);
  if( pNode ){
    jsonReturn(pNode, ctx, 0);
  }
  jsonParseReset(&x);
}

/*

  u32 i;

  if( argc<1 ) return;
  if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
  if( x.nNode ){
    for(i=1; i<(u32)argc; i++){
      zPath = (const char*)sqlite3_value_text(argv[i]);
      if( zPath==0 ) goto remove_done;

      pNode = jsonLookup(&x, zPath, 0, ctx, 0);
      if( x.nErr ) goto remove_done;
      if( pNode ) pNode->jnFlags |= JNODE_REMOVE;
    }
    if( (x.aNode[0].jnFlags & JNODE_REMOVE)==0 ){
      jsonReturnJson(x.aNode, ctx, 0);
    }
  }
remove_done:
  jsonParseReset(&x);
}

/*
** json_replace(JSON, PATH, VALUE, ...)
**
** Replace the value at PATH with VALUE.  If PATH does not already exist,

    return;
  }
  if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
  if( x.nNode ){
    for(i=1; i<(u32)argc; i+=2){
      u8 jnFlags = JNODE_REPLACE;
      zPath = (const char*)sqlite3_value_text(argv[i]);






      pNode = jsonLookup(&x, zPath, 0, ctx, &jnFlags);
      if( x.nErr ) goto replace_err;
      if( pNode ){
        pNode->jnFlags &= ~JNODE_JSON;
        pNode->jnFlags |= jnFlags;
        pNode->iVal = i+1;
      }
    }
    if( x.aNode[0].jnFlags & JNODE_REPLACE ){
      sqlite3_result_value(ctx, argv[x.aNode[0].iVal]);
    }else{
      jsonReturnJson(x.aNode, ctx, argv);
    }
  }
replace_err:
  jsonParseReset(&x);
}

/*
** json_set(JSON, PATH, VALUE, ...)
**
** Set the value at PATH to VALUE.  Create the PATH if it does not already

    return;
  }
  if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
  if( x.nNode ){
    for(i=1; i<(u32)argc; i+=2){
      u8 jnFlags = JNODE_REPLACE;
      zPath = (const char*)sqlite3_value_text(argv[i]);






      bApnd = 0;
      pNode = jsonLookup(&x, zPath, &bApnd, ctx, &jnFlags);
      if( x.oom ){
        sqlite3_result_error_nomem(ctx);
        goto jsonSetDone;
      }else if( x.nErr ){
        goto jsonSetDone;
      }else if( pNode && (bApnd || bIsSet) ){
        pNode->jnFlags &= ~JNODE_JSON;
        pNode->jnFlags |= jnFlags;
        pNode->iVal = i+1;
      }
    }

  sqlite3_context *ctx,
  int argc,
  sqlite3_value **argv
){
  JsonParse x;          /* The parse */
  const char *zPath;

  if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
  if( x.nNode ){
    JsonNode *pNode;
    if( argc==2 ){
      zPath = (const char*)sqlite3_value_text(argv[1]);


      pNode = jsonLookup(&x, zPath, 0, ctx, 0);
    }else{
      pNode = x.aNode;
    }




    if( pNode ){
      sqlite3_result_text(ctx, jsonType[pNode->eType], -1, SQLITE_STATIC);
    }
  }
  jsonParseReset(&x);
}

  UNUSED_PARAM(argc);
  jsonEachCursorReset(p);
  if( idxNum==0 ) return SQLITE_OK;
  z = (const char*)sqlite3_value_text(argv[0]);
  if( z==0 ) return SQLITE_OK;
  if( idxNum&2 ){
    zPath = (const char*)sqlite3_value_text(argv[1]);
    if( zPath==0 ) return SQLITE_OK;
    if( zPath[0]!='$' ){
      sqlite3_free(cur->pVtab->zErrMsg);
      cur->pVtab->zErrMsg = jsonPathSyntaxError(zPath);
      return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
    }
  }
  n = sqlite3_value_bytes(argv[0]);
  p->zJson = sqlite3_malloc64( n+1 );
  if( p->zJson==0 ) return SQLITE_NOMEM;
  memcpy(p->zJson, z, (size_t)n+1);
  if( jsonParse(&p->sParse, 0, p->zJson) ){
    int rc = SQLITE_NOMEM;
    if( p->sParse.oom==0 ){
      sqlite3_free(cur->pVtab->zErrMsg);
      cur->pVtab->zErrMsg = sqlite3_mprintf("malformed JSON");
      if( cur->pVtab->zErrMsg ) rc = SQLITE_ERROR;
    }
    jsonEachCursorReset(p);
    return rc;
  }else if( p->bRecursive && jsonParseFindParents(&p->sParse) ){

    jsonEachCursorReset(p);
    return SQLITE_NOMEM;
  }else{
    JsonNode *pNode;
    if( idxNum==3 ){
      const char *zErr = 0;
      p->bRecursive = 0;
      n = sqlite3_value_bytes(argv[1]);
      p->zPath = sqlite3_malloc64( n+1 );
      if( p->zPath==0 ) return SQLITE_NOMEM;
      memcpy(p->zPath, zPath, (size_t)n+1);
      pNode = jsonLookupStep(&p->sParse, 0, p->zPath+1, 0, &zErr);
      if( p->sParse.nErr ){
        sqlite3_free(cur->pVtab->zErrMsg);
        cur->pVtab->zErrMsg = jsonPathSyntaxError(zErr);
        jsonEachCursorReset(p);
        return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
      }else if( pNode==0 ){
        return SQLITE_OK;
      }
    }else{
      pNode = p->sParse.aNode;
    }
    p->i = (int)(pNode - p->sParse.aNode);
    p->eType = pNode->eType;