Function GenerateTermPath

pg_documentdb/src/opclass/bson_gin_core.c:1394–1653

static void
GenerateTermPath(bson_iter_t *bsonIter, const char *basePath,
				 uint32_t basePathLength, bool inArrayContext,
				 bool isArrayTerm, GenerateTermsContext *context,
				 bool isCheckForArrayTermsWithNestedDocument,
				 StringInfo pathStringInfo)
{
	const char *pathToInsert;
	uint32_t pathtoInsertLength;

	/* if array of array has not document inside it , we will not be generating parent path term */
	if (isCheckForArrayTermsWithNestedDocument && !BSON_ITER_HOLDS_DOCUMENT(bsonIter))
	{
		return;
	}

	const char *fieldName = bson_iter_key(bsonIter);
	uint32_t fieldNameLength = bson_iter_key_len(bsonIter);

	if (isArrayTerm)
	{
		/* if isArrayTerm is true (because we're inside an array context and we're generating */
		/* and we're building the non array-index based terms, then just use the base path) */
		/* this is because we can filter on array entries based on the array index (a.b.0 / a.b.1) */
		/* or simply on the array path itself (a.b) */
		pathToInsert = basePath;
		pathtoInsertLength = basePathLength;
	}
	else if (basePathLength == 0)
	{
		/* if we're at the root, simply use the field path. */
		pathToInsert = fieldName;
		pathtoInsertLength = fieldNameLength;
	}
	else
	{
		/* otherwise build the path to insert. We use 'base.field' for the path */
		/* since dot paths are illegal in field names. */
		uint32_t fieldPathLength = fieldNameLength;
		uint32_t pathToInsertAllocLength;

		/* the length includes the two fields + the extra dot. */
		pathtoInsertLength = fieldPathLength + basePathLength + 1;

		/* need one more character for the \0 */
		pathToInsertAllocLength = pathtoInsertLength + 1;

		if (pathStringInfo->len == 0)
		{
			/* if there's no temp buffer create one */
			enlargeStringInfo(pathStringInfo, pathToInsertAllocLength);
		}
		else if (pathStringInfo->len < (int) pathToInsertAllocLength)
		{
			/* if there's not enough space in the temp buffer, realloc to ensure enough length. */
			enlargeStringInfo(pathStringInfo, pathToInsertAllocLength);
		}