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Overview
Comment:Add the json_patch() SQL function to the JSON1 extension.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256:476088482024e411e2549b1697cdaf0124294c79d43f508c71c4eb66906a56fc
User & Date: drh 2017-03-23 23:44:55
Context
2017-03-24
12:35
Fix an error in the new json_patch() routine discovered by Ralf Junker. check-in: 9d535041 user: drh tags: trunk
2017-03-23
23:44
Add the json_patch() SQL function to the JSON1 extension. check-in: 47608848 user: drh tags: trunk
20:33
Change the name of the json_merge_patch() function to just json_patch(). Closed-Leaf check-in: 04d41004 user: drh tags: json_mergepatch
19:51
Improvement to the amalgamation configure.ac file contributed by Bob Friesenhahn. check-in: bf28a55d user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to ext/misc/json1.c.

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};

/* Bit values for the JsonNode.jnFlag field
*/
#define JNODE_RAW     0x01         /* Content is raw, not JSON encoded */
#define JNODE_ESCAPE  0x02         /* Content is text with \ escapes */
#define JNODE_REMOVE  0x04         /* Do not output */
#define JNODE_REPLACE 0x08         /* Replace with JsonNode.iVal */

#define JNODE_APPEND  0x10         /* More ARRAY/OBJECT entries at u.iAppend */
#define JNODE_LABEL   0x20         /* Is a label of an object */


/* A single node of parsed JSON
*/
struct JsonNode {
  u8 eType;              /* One of the JSON_ type values */
  u8 jnFlags;            /* JNODE flags */
  u8 iVal;               /* Replacement value when JNODE_REPLACE */
  u32 n;                 /* Bytes of content, or number of sub-nodes */
  union {
    const char *zJContent; /* Content for INT, REAL, and STRING */
    u32 iAppend;           /* More terms for ARRAY and OBJECT */
    u32 iKey;              /* Key for ARRAY objects in json_tree() */


  } u;
};

/* A completely parsed JSON string
*/
struct JsonParse {
  u32 nNode;         /* Number of slots of aNode[] used */
................................................................................
** the number of JsonNode objects that are encoded.
*/
static void jsonRenderNode(
  JsonNode *pNode,               /* The node to render */
  JsonString *pOut,              /* Write JSON here */
  sqlite3_value **aReplace       /* Replacement values */
){







  switch( pNode->eType ){
    default: {
      assert( pNode->eType==JSON_NULL );
      jsonAppendRaw(pOut, "null", 4);
      break;
    }
    case JSON_TRUE: {
................................................................................
      break;
    }
    case JSON_ARRAY: {
      u32 j = 1;
      jsonAppendChar(pOut, '[');
      for(;;){
        while( j<=pNode->n ){
          if( pNode[j].jnFlags & (JNODE_REMOVE|JNODE_REPLACE) ){
            if( pNode[j].jnFlags & JNODE_REPLACE ){
              jsonAppendSeparator(pOut);
              jsonAppendValue(pOut, aReplace[pNode[j].iVal]);
            }
          }else{
            jsonAppendSeparator(pOut);
            jsonRenderNode(&pNode[j], pOut, aReplace);
          }
          j += jsonNodeSize(&pNode[j]);
        }
        if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
        pNode = &pNode[pNode->u.iAppend];
................................................................................
      jsonAppendChar(pOut, '{');
      for(;;){
        while( j<=pNode->n ){
          if( (pNode[j+1].jnFlags & JNODE_REMOVE)==0 ){
            jsonAppendSeparator(pOut);
            jsonRenderNode(&pNode[j], pOut, aReplace);
            jsonAppendChar(pOut, ':');
            if( pNode[j+1].jnFlags & JNODE_REPLACE ){
              jsonAppendValue(pOut, aReplace[pNode[j+1].iVal]);
            }else{
              jsonRenderNode(&pNode[j+1], pOut, aReplace);
            }
          }
          j += 1 + jsonNodeSize(&pNode[j+1]);
        }
        if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
        pNode = &pNode[pNode->u.iAppend];
        j = 1;
      }
................................................................................
  JsonNode *p;
  if( pParse->nNode>=pParse->nAlloc ){
    return jsonParseAddNodeExpand(pParse, eType, n, zContent);
  }
  p = &pParse->aNode[pParse->nNode];
  p->eType = (u8)eType;
  p->jnFlags = 0;
  p->iVal = 0;
  p->n = n;
  p->u.zJContent = zContent;
  return pParse->nNode++;
}

/*
** Return true if z[] begins with 4 (or more) hexadecimal digits
................................................................................
    jsonAppendChar(&jx, ']');
    jsonResult(&jx);
    sqlite3_result_subtype(ctx, JSON_SUBTYPE);
  }
  jsonReset(&jx);
  jsonParseReset(&x);
}






































































































/*
** Implementation of the json_object(NAME,VALUE,...) function.  Return a JSON
** object that contains all name/value given in arguments.  Or if any name
** is not a string or if any value is a BLOB, throw an error.
*/
static void jsonObjectFunc(
................................................................................
  assert( x.nNode );
  for(i=1; i<(u32)argc; i+=2){
    zPath = (const char*)sqlite3_value_text(argv[i]);
    pNode = jsonLookup(&x, zPath, 0, ctx);
    if( x.nErr ) goto replace_err;
    if( pNode ){
      pNode->jnFlags |= (u8)JNODE_REPLACE;
      pNode->iVal = (u8)(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);
}

................................................................................
    if( x.oom ){
      sqlite3_result_error_nomem(ctx);
      goto jsonSetDone;
    }else if( x.nErr ){
      goto jsonSetDone;
    }else if( pNode && (bApnd || bIsSet) ){
      pNode->jnFlags |= (u8)JNODE_REPLACE;
      pNode->iVal = (u8)(i+1);
    }
  }
  if( x.aNode[0].jnFlags & JNODE_REPLACE ){
    sqlite3_result_value(ctx, argv[x.aNode[0].iVal]);
  }else{
    jsonReturnJson(x.aNode, ctx, argv);
  }
jsonSetDone:
  jsonParseReset(&x);
}

................................................................................
    { "json",                 1, 0,   jsonRemoveFunc        },
    { "json_array",          -1, 0,   jsonArrayFunc         },
    { "json_array_length",    1, 0,   jsonArrayLengthFunc   },
    { "json_array_length",    2, 0,   jsonArrayLengthFunc   },
    { "json_extract",        -1, 0,   jsonExtractFunc       },
    { "json_insert",         -1, 0,   jsonSetFunc           },
    { "json_object",         -1, 0,   jsonObjectFunc        },

    { "json_quote",           1, 0,   jsonQuoteFunc         },
    { "json_remove",         -1, 0,   jsonRemoveFunc        },
    { "json_replace",        -1, 0,   jsonReplaceFunc       },
    { "json_set",            -1, 1,   jsonSetFunc           },
    { "json_type",            1, 0,   jsonTypeFunc          },
    { "json_type",            2, 0,   jsonTypeFunc          },
    { "json_valid",           1, 0,   jsonValidFunc         },







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};

/* Bit values for the JsonNode.jnFlag field
*/
#define JNODE_RAW     0x01         /* Content is raw, not JSON encoded */
#define JNODE_ESCAPE  0x02         /* Content is text with \ escapes */
#define JNODE_REMOVE  0x04         /* Do not output */
#define JNODE_REPLACE 0x08         /* Replace with JsonNode.u.iReplace */
#define JNODE_PATCH   0x10         /* Patch with JsonNode.u.pPatch */
#define JNODE_APPEND  0x20         /* More ARRAY/OBJECT entries at u.iAppend */
#define JNODE_LABEL   0x40         /* Is a label of an object */


/* A single node of parsed JSON
*/
struct JsonNode {
  u8 eType;              /* One of the JSON_ type values */
  u8 jnFlags;            /* JNODE flags */

  u32 n;                 /* Bytes of content, or number of sub-nodes */
  union {
    const char *zJContent; /* Content for INT, REAL, and STRING */
    u32 iAppend;           /* More terms for ARRAY and OBJECT */
    u32 iKey;              /* Key for ARRAY objects in json_tree() */
    u32 iReplace;          /* Replacement content for JNODE_REPLACE */
    JsonNode *pPatch;      /* Node chain of patch for JNODE_PATCH */
  } u;
};

/* A completely parsed JSON string
*/
struct JsonParse {
  u32 nNode;         /* Number of slots of aNode[] used */
................................................................................
** the number of JsonNode objects that are encoded.
*/
static void jsonRenderNode(
  JsonNode *pNode,               /* The node to render */
  JsonString *pOut,              /* Write JSON here */
  sqlite3_value **aReplace       /* Replacement values */
){
  if( pNode->jnFlags & (JNODE_REPLACE|JNODE_PATCH) ){
    if( pNode->jnFlags & JNODE_REPLACE ){
      jsonAppendValue(pOut, aReplace[pNode->u.iReplace]);
      return;
    }
    pNode = pNode->u.pPatch;
  }
  switch( pNode->eType ){
    default: {
      assert( pNode->eType==JSON_NULL );
      jsonAppendRaw(pOut, "null", 4);
      break;
    }
    case JSON_TRUE: {
................................................................................
      break;
    }
    case JSON_ARRAY: {
      u32 j = 1;
      jsonAppendChar(pOut, '[');
      for(;;){
        while( j<=pNode->n ){

          if( (pNode[j].jnFlags & JNODE_REMOVE)==0 ){




            jsonAppendSeparator(pOut);
            jsonRenderNode(&pNode[j], pOut, aReplace);
          }
          j += jsonNodeSize(&pNode[j]);
        }
        if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
        pNode = &pNode[pNode->u.iAppend];
................................................................................
      jsonAppendChar(pOut, '{');
      for(;;){
        while( j<=pNode->n ){
          if( (pNode[j+1].jnFlags & JNODE_REMOVE)==0 ){
            jsonAppendSeparator(pOut);
            jsonRenderNode(&pNode[j], pOut, aReplace);
            jsonAppendChar(pOut, ':');



            jsonRenderNode(&pNode[j+1], pOut, aReplace);

          }
          j += 1 + jsonNodeSize(&pNode[j+1]);
        }
        if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
        pNode = &pNode[pNode->u.iAppend];
        j = 1;
      }
................................................................................
  JsonNode *p;
  if( pParse->nNode>=pParse->nAlloc ){
    return jsonParseAddNodeExpand(pParse, eType, n, zContent);
  }
  p = &pParse->aNode[pParse->nNode];
  p->eType = (u8)eType;
  p->jnFlags = 0;

  p->n = n;
  p->u.zJContent = zContent;
  return pParse->nNode++;
}

/*
** Return true if z[] begins with 4 (or more) hexadecimal digits
................................................................................
    jsonAppendChar(&jx, ']');
    jsonResult(&jx);
    sqlite3_result_subtype(ctx, JSON_SUBTYPE);
  }
  jsonReset(&jx);
  jsonParseReset(&x);
}

/* This is the RFC 7396 MergePatch algorithm.
*/
static JsonNode *jsonMergePatch(
  JsonParse *pParse,   /* The JSON parser that contains the TARGET */
  int iTarget,         /* Node of the TARGET in pParse */
  JsonNode *pPatch     /* The PATCH */
){
  u32 i, j;
  u32 iRoot;
  JsonNode *pTarget;
  if( pPatch->eType!=JSON_OBJECT ){
    return pPatch;
  }
  assert( iTarget>=0 && iTarget<pParse->nNode );
  pTarget = &pParse->aNode[iTarget];
  assert( (pPatch->jnFlags & JNODE_APPEND)==0 );
  if( pTarget->eType!=JSON_OBJECT ){
    for(i=2; i<=pPatch->n; i += jsonNodeSize(&pPatch[i])+1){
      if( pPatch[i].eType==JSON_NULL ){
        pPatch[i].jnFlags |= JNODE_REMOVE;
      }
    }
    return pPatch;
  }
  iRoot = iTarget;
  for(i=1; i<pPatch->n; i += jsonNodeSize(&pPatch[i+1])+1){
    int nKey;
    const char *zKey;
    assert( pPatch[i].eType==JSON_STRING );
    assert( pPatch[i].jnFlags & JNODE_LABEL );
    nKey = pPatch[i].n;
    zKey = pPatch[i].u.zJContent;
    assert( (pPatch[i].jnFlags & JNODE_RAW)==0 );
    for(j=1; j<pTarget->n; j += jsonNodeSize(&pTarget[j+1])+1 ){
      assert( pTarget[j].eType==JSON_STRING );
      assert( pTarget[j].jnFlags & JNODE_LABEL );
      assert( (pPatch[i].jnFlags & JNODE_RAW)==0 );
      if( pTarget[j].n==nKey && strncmp(pTarget[j].u.zJContent,zKey,nKey)==0 ){
        if( pTarget[j+1].jnFlags & (JNODE_REMOVE|JNODE_PATCH) ) break;
        if( pPatch[i+1].eType==JSON_NULL ){
          pTarget[j+1].jnFlags |= JNODE_REMOVE;
        }else{
          JsonNode *pNew = jsonMergePatch(pParse, iTarget+j+1, &pPatch[i+1]);
          if( pNew==0 ) return 0;
          pTarget = &pParse->aNode[iTarget];
          if( pNew!=&pTarget[j+1] ){
            pTarget[j+1].u.pPatch = pNew;
            pTarget[j+1].jnFlags |= JNODE_PATCH;
          }
        }
        break;
      }
    }
    if( j>=pTarget->n && pPatch[i+1].eType!=JSON_NULL ){
      int iStart, iPatch;
      iStart = jsonParseAddNode(pParse, JSON_OBJECT, 2, 0);
      jsonParseAddNode(pParse, JSON_STRING, nKey, zKey);
      iPatch = jsonParseAddNode(pParse, JSON_TRUE, 0, 0);
      if( pParse->oom ) return 0;
      pTarget = &pParse->aNode[iTarget];
      pParse->aNode[iRoot].jnFlags |= JNODE_APPEND;
      pParse->aNode[iRoot].u.iAppend = iStart - iRoot;
      iRoot = iStart;
      pParse->aNode[iPatch].jnFlags |= JNODE_PATCH;
      pParse->aNode[iPatch].u.pPatch = &pPatch[i+1];
    }
  }
  return pTarget;
}

/*
** Implementation of the json_mergepatch(JSON1,JSON2) function.  Return a JSON
** object that is the result of running the RFC 7396 MergePatch() algorithm
** on the two arguments.
*/
static void jsonPatchFunc(
  sqlite3_context *ctx,
  int argc,
  sqlite3_value **argv
){
  JsonParse x;     /* The JSON that is being patched */
  JsonParse y;     /* The patch */
  JsonNode *pResult;   /* The result of the merge */

  if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
  if( jsonParse(&y, ctx, (const char*)sqlite3_value_text(argv[1])) ){
    jsonParseReset(&x);
    return;
  }
  pResult = jsonMergePatch(&x, 0, y.aNode);
  assert( pResult!=0 || x.oom );
  if( pResult ){
    jsonReturnJson(pResult, ctx, 0);
  }else{
    sqlite3_result_error_nomem(ctx);
  }
  jsonParseReset(&x);
  jsonParseReset(&y);
}


/*
** Implementation of the json_object(NAME,VALUE,...) function.  Return a JSON
** object that contains all name/value given in arguments.  Or if any name
** is not a string or if any value is a BLOB, throw an error.
*/
static void jsonObjectFunc(
................................................................................
  assert( x.nNode );
  for(i=1; i<(u32)argc; i+=2){
    zPath = (const char*)sqlite3_value_text(argv[i]);
    pNode = jsonLookup(&x, zPath, 0, ctx);
    if( x.nErr ) goto replace_err;
    if( pNode ){
      pNode->jnFlags |= (u8)JNODE_REPLACE;
      pNode->u.iReplace = i + 1;
    }
  }
  if( x.aNode[0].jnFlags & JNODE_REPLACE ){
    sqlite3_result_value(ctx, argv[x.aNode[0].u.iReplace]);
  }else{
    jsonReturnJson(x.aNode, ctx, argv);
  }
replace_err:
  jsonParseReset(&x);
}

................................................................................
    if( x.oom ){
      sqlite3_result_error_nomem(ctx);
      goto jsonSetDone;
    }else if( x.nErr ){
      goto jsonSetDone;
    }else if( pNode && (bApnd || bIsSet) ){
      pNode->jnFlags |= (u8)JNODE_REPLACE;
      pNode->u.iReplace = i + 1;
    }
  }
  if( x.aNode[0].jnFlags & JNODE_REPLACE ){
    sqlite3_result_value(ctx, argv[x.aNode[0].u.iReplace]);
  }else{
    jsonReturnJson(x.aNode, ctx, argv);
  }
jsonSetDone:
  jsonParseReset(&x);
}

................................................................................
    { "json",                 1, 0,   jsonRemoveFunc        },
    { "json_array",          -1, 0,   jsonArrayFunc         },
    { "json_array_length",    1, 0,   jsonArrayLengthFunc   },
    { "json_array_length",    2, 0,   jsonArrayLengthFunc   },
    { "json_extract",        -1, 0,   jsonExtractFunc       },
    { "json_insert",         -1, 0,   jsonSetFunc           },
    { "json_object",         -1, 0,   jsonObjectFunc        },
    { "json_patch",           2, 0,   jsonPatchFunc         },
    { "json_quote",           1, 0,   jsonQuoteFunc         },
    { "json_remove",         -1, 0,   jsonRemoveFunc        },
    { "json_replace",        -1, 0,   jsonReplaceFunc       },
    { "json_set",            -1, 1,   jsonSetFunc           },
    { "json_type",            1, 0,   jsonTypeFunc          },
    { "json_type",            2, 0,   jsonTypeFunc          },
    { "json_valid",           1, 0,   jsonValidFunc         },

Added test/json104.test.





































































































































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# 2017-03-22
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements tests for json_patch(A,B) SQL function.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !json1 {
  finish_test
  return
}

# This is the example from pages 2 and 3 of RFC-7396
do_execsql_test json104-100 {
  SELECT json_patch('{
       "a": "b",
       "c": {
         "d": "e",
         "f": "g"
       }
     }','{
       "a":"z",
       "c": {
         "f": null
       }
     }');
} {{{"a":"z","c":{"d":"e"}}}}


# This is the example from pages 4 and 5 of RFC-7396 
do_execsql_test json104-110 {
  SELECT json_patch('{
       "title": "Goodbye!",
       "author" : {
         "givenName" : "John",
         "familyName" : "Doe"
       },
       "tags":[ "example", "sample" ],
       "content": "This will be unchanged"
     }','{
       "title": "Hello!",
       "phoneNumber": "+01-123-456-7890",
       "author": {
         "familyName": null
       },
       "tags": [ "example" ]
     }');
} {{{"title":"Hello!","author":{"givenName":"John"},"tags":["example"],"content":"This will be unchanged","phoneNumber":"+01-123-456-7890"}}}

do_execsql_test json104-200 {
  SELECT json_patch('[1,2,3]','{"x":null}');
} {{{}}}
do_execsql_test json104-210 {
  SELECT json_patch('[1,2,3]','{"x":null,"y":1,"z":null}');
} {{{"y":1}}}

finish_test