1 /* 2 * 3 * Copyright 2015 gRPC authors. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 19 /* The idea of the writer is basically symmetrical of the reader. While the 20 * reader emits various calls to your code, the writer takes basically the 21 * same calls and emit json out of it. It doesn't try to make any check on 22 * the order of the calls you do on it. Meaning you can theorically force 23 * it to generate invalid json. 24 * 25 * Also, unlike the reader, the writer expects UTF-8 encoded input strings. 26 * These strings will be UTF-8 validated, and any invalid character will 27 * cut the conversion short, before any invalid UTF-8 sequence, thus forming 28 * a valid UTF-8 string overall. 29 */ 30 31 #ifndef GRPC_CORE_LIB_JSON_JSON_WRITER_H 32 #define GRPC_CORE_LIB_JSON_JSON_WRITER_H 33 34 #include <grpc/support/port_platform.h> 35 36 #include <stdlib.h> 37 38 #include "src/core/lib/json/json_common.h" 39 40 typedef struct grpc_json_writer_vtable { 41 /* Adds a character to the output stream. */ 42 void (*output_char)(void* userdata, char); 43 /* Adds a zero-terminated string to the output stream. */ 44 void (*output_string)(void* userdata, const char* str); 45 /* Adds a fixed-length string to the output stream. */ 46 void (*output_string_with_len)(void* userdata, const char* str, size_t len); 47 48 } grpc_json_writer_vtable; 49 50 typedef struct grpc_json_writer { 51 void* userdata; 52 grpc_json_writer_vtable* vtable; 53 int indent; 54 int depth; 55 int container_empty; 56 int got_key; 57 } grpc_json_writer; 58 59 /* Call this to initialize your writer structure. The indent parameter is 60 * specifying the number of spaces to use for indenting the output. If you 61 * use indent=0, then the output will not have any newlines either, thus 62 * emitting a condensed json output. 63 */ 64 void grpc_json_writer_init(grpc_json_writer* writer, int indent, 65 grpc_json_writer_vtable* vtable, void* userdata); 66 67 /* Signals the beginning of a container. */ 68 void grpc_json_writer_container_begins(grpc_json_writer* writer, 69 grpc_json_type type); 70 /* Signals the end of a container. */ 71 void grpc_json_writer_container_ends(grpc_json_writer* writer, 72 grpc_json_type type); 73 /* Writes down an object key for the next value. */ 74 void grpc_json_writer_object_key(grpc_json_writer* writer, const char* string); 75 /* Sets a raw value. Useful for numbers. */ 76 void grpc_json_writer_value_raw(grpc_json_writer* writer, const char* string); 77 /* Sets a raw value with its length. Useful for values like true or false. */ 78 void grpc_json_writer_value_raw_with_len(grpc_json_writer* writer, 79 const char* string, size_t len); 80 /* Sets a string value. It'll be escaped, and utf-8 validated. */ 81 void grpc_json_writer_value_string(grpc_json_writer* writer, 82 const char* string); 83 84 #endif /* GRPC_CORE_LIB_JSON_JSON_WRITER_H */ 85