1 files changed, 112 insertions, 0 deletions
diff --git a/upb/json/parser.h b/upb/json/parser.h
new file mode 100644
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+++ b/upb/json/parser.h
@@ -0,0 +1,112 @@
+/*
+ * upb - a minimalist implementation of protocol buffers.
+ *
+ * Copyright (c) 2014 Google Inc.  See LICENSE for details.
+ * Author: Josh Haberman <jhaberman@gmail.com>
+ *
+ * upb::json::Parser can parse JSON according to a specific schema.
+ * Support for parsing arbitrary JSON (schema-less) will be added later.
+ */
+
+#ifndef UPB_JSON_PARSER_H_
+#define UPB_JSON_PARSER_H_
+
+#include "upb/sink.h"
+
+#ifdef __cplusplus
+namespace upb {
+namespace json {
+class Parser;
+}  // namespace json
+}  // namespace upb
+#endif
+
+UPB_DECLARE_TYPE(upb::json::Parser, upb_json_parser);
+
+// Internal-only struct used by the parser.
+typedef struct {
+ UPB_PRIVATE_FOR_CPP
+  upb_sink sink;
+  const upb_msgdef *m;
+  const upb_fielddef *f;
+} upb_jsonparser_frame;
+
+
+/* upb::json::Parser **********************************************************/
+
+#define UPB_JSON_MAX_DEPTH 64
+
+// Parses an incoming BytesStream, pushing the results to the destination sink.
+UPB_DEFINE_CLASS0(upb::json::Parser,
+ public:
+  Parser(Status* status);
+  ~Parser();
+
+  // Resets the state of the printer, so that it will expect to begin a new
+  // document.
+  void Reset();
+
+  // Resets the output pointer which will serve as our closure.  Implies
+  // Reset().
+  void ResetOutput(Sink* output);
+
+  // The input to the printer.
+  BytesSink* input();
+,
+UPB_DEFINE_STRUCT0(upb_json_parser,
+  upb_byteshandler input_handler_;
+  upb_bytessink input_;
+
+  // Stack to track the JSON scopes we are in.
+  upb_jsonparser_frame stack[UPB_JSON_MAX_DEPTH];
+  upb_jsonparser_frame *top;
+  upb_jsonparser_frame *limit;
+
+  upb_status *status;
+
+  // Ragel's internal parsing stack for the parsing state machine.
+  int current_state;
+  int parser_stack[UPB_JSON_MAX_DEPTH];
+  int parser_top;
+
+  // A pointer to the beginning of whatever text we are currently parsing.
+  const char *text_begin;
+
+  // We have to accumulate text for member names, integers, unicode escapes, and
+  // base64 partial results.
+  const char *accumulated;
+  size_t accumulated_len;
+  // TODO: add members and code for allocating a buffer when necessary (when the
+  // member spans input buffers or contains escapes).
+));
+
+UPB_BEGIN_EXTERN_C
+
+void upb_json_parser_init(upb_json_parser *p, upb_status *status);
+void upb_json_parser_uninit(upb_json_parser *p);
+void upb_json_parser_reset(upb_json_parser *p);
+void upb_json_parser_resetoutput(upb_json_parser *p, upb_sink *output);
+upb_bytessink *upb_json_parser_input(upb_json_parser *p);
+
+UPB_END_EXTERN_C
+
+#ifdef __cplusplus
+
+namespace upb {
+namespace json {
+inline Parser::Parser(Status* status) { upb_json_parser_init(this, status); }
+inline Parser::~Parser() { upb_json_parser_uninit(this); }
+inline void Parser::Reset() { upb_json_parser_reset(this); }
+inline void Parser::ResetOutput(Sink* output) {
+  upb_json_parser_resetoutput(this, output);
+}
+inline BytesSink* Parser::input() {
+  return upb_json_parser_input(this);
+}
+}  // namespace json
+}  // namespace upb
+
+#endif
+
+
+#endif  // UPB_JSON_PARSER_H_