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sqlite3.c  view on Meta::CPAN

/* True if the string is all alphanumerics and underscores */
static int jsonAllAlphanum(const char *z, int n){
  int i;
  for(i=0; i<n && (sqlite3Isalnum(z[i]) || z[i]=='_'); i++){}
  return i==n;
}

/*
** json_extract(JSON, PATH, ...)
** "->"(JSON,PATH)
** "->>"(JSON,PATH)
**
** Return the element described by PATH.  Return NULL if that PATH element
** is not found.
**
** If JSON_JSON is set or if more that one PATH argument is supplied then
** always return a JSON representation of the result.  If JSON_SQL is set,
** then always return an SQL representation of the result.  If neither flag
** is present and argc==2, then return JSON for objects and arrays and SQL
** for all other values.
**
** When multiple PATH arguments are supplied, the result is a JSON array
** containing the result of each PATH.
**
** Abbreviated JSON path expressions are allows if JSON_ABPATH, for
** compatibility with PG.
*/
static void jsonExtractFunc(
  sqlite3_context *ctx,
  int argc,
  sqlite3_value **argv
){
  JsonParse *p = 0;      /* The parse */
  int flags;             /* Flags associated with the function */
  int i;                 /* Loop counter */
  JsonString jx;         /* String for array result */

  if( argc<2 ) return;
  p = jsonParseFuncArg(ctx, argv[0], 0);
  if( p==0 ) return;
  flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
  jsonStringInit(&jx, ctx);
  if( argc>2 ){
    jsonAppendChar(&jx, '[');
  }
  for(i=1; i<argc; i++){
    /* With a single PATH argument */
    const char *zPath = (const char*)sqlite3_value_text(argv[i]);
    int nPath;
    u32 j;
    if( zPath==0 ) goto json_extract_error;
    nPath = sqlite3Strlen30(zPath);
    if( zPath[0]=='$' ){
      j = jsonLookupStep(p, 0, zPath+1, 0);
    }else if( (flags & JSON_ABPATH) ){
      /* The -> and ->> operators accept abbreviated PATH arguments.  This
      ** is mostly for compatibility with PostgreSQL, but also for
      ** convenience.
      **
      **     NUMBER   ==>  $[NUMBER]     // PG compatible
      **     LABEL    ==>  $.LABEL       // PG compatible
      **     [NUMBER] ==>  $[NUMBER]     // Not PG.  Purely for convenience
      **
      ** Updated 2024-05-27:  If the NUMBER is negative, then PG counts from
      ** the right of the array.  Hence for negative NUMBER:
      **
      **     NUMBER   ==>  $[#NUMBER]    // PG compatible
      */
      jsonStringInit(&jx, ctx);
      if( sqlite3_value_type(argv[i])==SQLITE_INTEGER ){
        jsonAppendRawNZ(&jx, "[", 1);
        if( zPath[0]=='-' ) jsonAppendRawNZ(&jx,"#",1);
        jsonAppendRaw(&jx, zPath, nPath);
        jsonAppendRawNZ(&jx, "]", 2);
      }else if( jsonAllAlphanum(zPath, nPath) ){
        jsonAppendRawNZ(&jx, ".", 1);
        jsonAppendRaw(&jx, zPath, nPath);
      }else if( zPath[0]=='[' && nPath>=3 && zPath[nPath-1]==']' ){
        jsonAppendRaw(&jx, zPath, nPath);
      }else{
        jsonAppendRawNZ(&jx, ".\"", 2);
        jsonAppendRaw(&jx, zPath, nPath);
        jsonAppendRawNZ(&jx, "\"", 1);
      }
      jsonStringTerminate(&jx);
      j = jsonLookupStep(p, 0, jx.zBuf, 0);
      jsonStringReset(&jx);
    }else{
      jsonBadPathError(ctx, zPath);
      goto json_extract_error;
    }
    if( j<p->nBlob ){
      if( argc==2 ){
        if( flags & JSON_JSON ){
          jsonStringInit(&jx, ctx);
          jsonTranslateBlobToText(p, j, &jx);
          jsonReturnString(&jx, 0, 0);
          jsonStringReset(&jx);
          assert( (flags & JSON_BLOB)==0 );
          sqlite3_result_subtype(ctx, JSON_SUBTYPE);
        }else{
          jsonReturnFromBlob(p, j, ctx, 0);
          if( (flags & (JSON_SQL|JSON_BLOB))==0
           && (p->aBlob[j]&0x0f)>=JSONB_ARRAY
          ){
            sqlite3_result_subtype(ctx, JSON_SUBTYPE);
          }
        }
      }else{
        jsonAppendSeparator(&jx);
        jsonTranslateBlobToText(p, j, &jx);
      }
    }else if( j==JSON_LOOKUP_NOTFOUND ){
      if( argc==2 ){
        goto json_extract_error;  /* Return NULL if not found */
      }else{
        jsonAppendSeparator(&jx);
        jsonAppendRawNZ(&jx, "null", 4);
      }
    }else if( j==JSON_LOOKUP_ERROR ){
      sqlite3_result_error(ctx, "malformed JSON", -1);
      goto json_extract_error;
    }else{
      jsonBadPathError(ctx, zPath);
      goto json_extract_error;
    }
  }