Merge github.com:grpc/grpc into fuzzy-bits

8 files changed, 1757 insertions, 0 deletions

diff --git a/src/core/lib/json/json.c b/src/core/lib/json/json.c
new file mode 100644
index 0000000000..9793045d91
--- /dev/null
+++ b/src/core/lib/json/json.c
@@ -0,0 +1,64 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+
+#include "src/core/lib/json/json.h"
+
+grpc_json *grpc_json_create(grpc_json_type type) {
+  grpc_json *json = gpr_malloc(sizeof(*json));
+  memset(json, 0, sizeof(*json));
+  json->type = type;
+
+  return json;
+}
+
+void grpc_json_destroy(grpc_json *json) {
+  while (json->child) {
+    grpc_json_destroy(json->child);
+  }
+
+  if (json->next) {
+    json->next->prev = json->prev;
+  }
+
+  if (json->prev) {
+    json->prev->next = json->next;
+  } else if (json->parent) {
+    json->parent->child = json->next;
+  }
+
+  gpr_free(json);
+}
diff --git a/src/core/lib/json/json.h b/src/core/lib/json/json.h
new file mode 100644
index 0000000000..41d87dd5ce
--- /dev/null
+++ b/src/core/lib/json/json.h
@@ -0,0 +1,88 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_JSON_JSON_H
+#define GRPC_CORE_LIB_JSON_JSON_H
+
+#include <stdlib.h>
+
+#include "src/core/lib/json/json_common.h"
+
+/* A tree-like structure to hold json values. The key and value pointers
+ * are not owned by it.
+ */
+typedef struct grpc_json {
+  struct grpc_json *next;
+  struct grpc_json *prev;
+  struct grpc_json *child;
+  struct grpc_json *parent;
+
+  grpc_json_type type;
+  const char *key;
+  const char *value;
+} grpc_json;
+
+/* The next two functions are going to parse the input string, and
+ * modify it in the process, in order to use its space to store
+ * all of the keys and values for the returned object tree.
+ *
+ * They assume UTF-8 input stream, and will output UTF-8 encoded
+ * strings in the tree. The input stream's UTF-8 isn't validated,
+ * as in, what you input is what you get as an output.
+ *
+ * All the keys and values in the grpc_json objects will be strings
+ * pointing at your input buffer.
+ *
+ * Delete the allocated tree afterward using grpc_json_destroy().
+ */
+grpc_json *grpc_json_parse_string_with_len(char *input, size_t size);
+grpc_json *grpc_json_parse_string(char *input);
+
+/* This function will create a new string using gpr_realloc, and will
+ * deserialize the grpc_json tree into it. It'll be zero-terminated,
+ * but will be allocated in chunks of 256 bytes.
+ *
+ * The indent parameter controls the way the output is formatted.
+ * If indent is 0, then newlines will be suppressed as well, and the
+ * output will be condensed at its maximum.
+ */
+char *grpc_json_dump_to_string(grpc_json *json, int indent);
+
+/* Use these to create or delete a grpc_json object.
+ * Deletion is recursive. We will not attempt to free any of the strings
+ * in any of the objects of that tree.
+ */
+grpc_json *grpc_json_create(grpc_json_type type);
+void grpc_json_destroy(grpc_json *json);
+
+#endif /* GRPC_CORE_LIB_JSON_JSON_H */
diff --git a/src/core/lib/json/json_common.h b/src/core/lib/json/json_common.h
new file mode 100644
index 0000000000..ce980040f8
--- /dev/null
+++ b/src/core/lib/json/json_common.h
@@ -0,0 +1,49 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_JSON_JSON_COMMON_H
+#define GRPC_CORE_LIB_JSON_JSON_COMMON_H
+
+/* The various json types. */
+typedef enum {
+  GRPC_JSON_OBJECT,
+  GRPC_JSON_ARRAY,
+  GRPC_JSON_STRING,
+  GRPC_JSON_NUMBER,
+  GRPC_JSON_TRUE,
+  GRPC_JSON_FALSE,
+  GRPC_JSON_NULL,
+  GRPC_JSON_TOP_LEVEL
+} grpc_json_type;
+
+#endif /* GRPC_CORE_LIB_JSON_JSON_COMMON_H */
diff --git a/src/core/lib/json/json_reader.c b/src/core/lib/json/json_reader.c
new file mode 100644
index 0000000000..4cff13dff1
--- /dev/null
+++ b/src/core/lib/json/json_reader.c
@@ -0,0 +1,662 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <string.h>
+
+#include <grpc/support/port_platform.h>
+
+#include <grpc/support/log.h>
+
+#include "src/core/lib/json/json_reader.h"
+
+static void json_reader_string_clear(grpc_json_reader *reader) {
+  reader->vtable->string_clear(reader->userdata);
+}
+
+static void json_reader_string_add_char(grpc_json_reader *reader, uint32_t c) {
+  reader->vtable->string_add_char(reader->userdata, c);
+}
+
+static void json_reader_string_add_utf32(grpc_json_reader *reader,
+                                         uint32_t utf32) {
+  reader->vtable->string_add_utf32(reader->userdata, utf32);
+}
+
+static uint32_t grpc_json_reader_read_char(grpc_json_reader *reader) {
+  return reader->vtable->read_char(reader->userdata);
+}
+
+static void json_reader_container_begins(grpc_json_reader *reader,
+                                         grpc_json_type type) {
+  reader->vtable->container_begins(reader->userdata, type);
+}
+
+static grpc_json_type grpc_json_reader_container_ends(
+    grpc_json_reader *reader) {
+  return reader->vtable->container_ends(reader->userdata);
+}
+
+static void json_reader_set_key(grpc_json_reader *reader) {
+  reader->vtable->set_key(reader->userdata);
+}
+
+static void json_reader_set_string(grpc_json_reader *reader) {
+  reader->vtable->set_string(reader->userdata);
+}
+
+static int json_reader_set_number(grpc_json_reader *reader) {
+  return reader->vtable->set_number(reader->userdata);
+}
+
+static void json_reader_set_true(grpc_json_reader *reader) {
+  reader->vtable->set_true(reader->userdata);
+}
+
+static void json_reader_set_false(grpc_json_reader *reader) {
+  reader->vtable->set_false(reader->userdata);
+}
+
+static void json_reader_set_null(grpc_json_reader *reader) {
+  reader->vtable->set_null(reader->userdata);
+}
+
+/* Call this function to initialize the reader structure. */
+void grpc_json_reader_init(grpc_json_reader *reader,
+                           grpc_json_reader_vtable *vtable, void *userdata) {
+  memset(reader, 0, sizeof(*reader));
+  reader->vtable = vtable;
+  reader->userdata = userdata;
+  json_reader_string_clear(reader);
+  reader->state = GRPC_JSON_STATE_VALUE_BEGIN;
+}
+
+int grpc_json_reader_is_complete(grpc_json_reader *reader) {
+  return ((reader->depth == 0) &&
+          ((reader->state == GRPC_JSON_STATE_END) ||
+           (reader->state == GRPC_JSON_STATE_VALUE_END)));
+}
+
+grpc_json_reader_status grpc_json_reader_run(grpc_json_reader *reader) {
+  uint32_t c, success;
+
+  /* This state-machine is a strict implementation of ECMA-404 */
+  for (;;) {
+    c = grpc_json_reader_read_char(reader);
+    switch (c) {
+      /* Let's process the error cases first. */
+      case GRPC_JSON_READ_CHAR_ERROR:
+        return GRPC_JSON_READ_ERROR;
+
+      case GRPC_JSON_READ_CHAR_EAGAIN:
+        return GRPC_JSON_EAGAIN;
+
+      case GRPC_JSON_READ_CHAR_EOF:
+        if (grpc_json_reader_is_complete(reader)) {
+          return GRPC_JSON_DONE;
+        } else {
+          return GRPC_JSON_PARSE_ERROR;
+        }
+        break;
+
+      /* Processing whitespaces. */
+      case ' ':
+      case '\t':
+      case '\n':
+      case '\r':
+        switch (reader->state) {
+          case GRPC_JSON_STATE_OBJECT_KEY_BEGIN:
+          case GRPC_JSON_STATE_OBJECT_KEY_END:
+          case GRPC_JSON_STATE_VALUE_BEGIN:
+          case GRPC_JSON_STATE_VALUE_END:
+          case GRPC_JSON_STATE_END:
+            break;
+
+          case GRPC_JSON_STATE_OBJECT_KEY_STRING:
+          case GRPC_JSON_STATE_VALUE_STRING:
+            if (c != ' ') return GRPC_JSON_PARSE_ERROR;
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
+            json_reader_string_add_char(reader, c);
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER:
+          case GRPC_JSON_STATE_VALUE_NUMBER_WITH_DECIMAL:
+          case GRPC_JSON_STATE_VALUE_NUMBER_ZERO:
+          case GRPC_JSON_STATE_VALUE_NUMBER_EPM:
+            success = (uint32_t)json_reader_set_number(reader);
+            if (!success) return GRPC_JSON_PARSE_ERROR;
+            json_reader_string_clear(reader);
+            reader->state = GRPC_JSON_STATE_VALUE_END;
+            break;
+
+          default:
+            return GRPC_JSON_PARSE_ERROR;
+        }
+        break;
+
+      /* Value, object or array terminations. */
+      case ',':
+      case '}':
+      case ']':
+        switch (reader->state) {
+          case GRPC_JSON_STATE_OBJECT_KEY_STRING:
+          case GRPC_JSON_STATE_VALUE_STRING:
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
+            json_reader_string_add_char(reader, c);
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER:
+          case GRPC_JSON_STATE_VALUE_NUMBER_WITH_DECIMAL:
+          case GRPC_JSON_STATE_VALUE_NUMBER_ZERO:
+          case GRPC_JSON_STATE_VALUE_NUMBER_EPM:
+            success = (uint32_t)json_reader_set_number(reader);
+            if (!success) return GRPC_JSON_PARSE_ERROR;
+            json_reader_string_clear(reader);
+            reader->state = GRPC_JSON_STATE_VALUE_END;
+          /* The missing break here is intentional. */
+
+          case GRPC_JSON_STATE_VALUE_END:
+          case GRPC_JSON_STATE_OBJECT_KEY_BEGIN:
+          case GRPC_JSON_STATE_VALUE_BEGIN:
+            if (c == ',') {
+              if (reader->state != GRPC_JSON_STATE_VALUE_END) {
+                return GRPC_JSON_PARSE_ERROR;
+              }
+              if (reader->in_object) {
+                reader->state = GRPC_JSON_STATE_OBJECT_KEY_BEGIN;
+              } else {
+                reader->state = GRPC_JSON_STATE_VALUE_BEGIN;
+              }
+            } else {
+              if (reader->depth-- == 0) return GRPC_JSON_PARSE_ERROR;
+              if ((c == '}') && !reader->in_object) {
+                return GRPC_JSON_PARSE_ERROR;
+              }
+              if ((c == '}') &&
+                  (reader->state == GRPC_JSON_STATE_OBJECT_KEY_BEGIN) &&
+                  !reader->container_just_begun) {
+                return GRPC_JSON_PARSE_ERROR;
+              }
+              if ((c == ']') && !reader->in_array) return GRPC_JSON_PARSE_ERROR;
+              if ((c == ']') &&
+                  (reader->state == GRPC_JSON_STATE_VALUE_BEGIN) &&
+                  !reader->container_just_begun) {
+                return GRPC_JSON_PARSE_ERROR;
+              }
+              reader->state = GRPC_JSON_STATE_VALUE_END;
+              switch (grpc_json_reader_container_ends(reader)) {
+                case GRPC_JSON_OBJECT:
+                  reader->in_object = 1;
+                  reader->in_array = 0;
+                  break;
+                case GRPC_JSON_ARRAY:
+                  reader->in_object = 0;
+                  reader->in_array = 1;
+                  break;
+                case GRPC_JSON_TOP_LEVEL:
+                  GPR_ASSERT(reader->depth == 0);
+                  reader->in_object = 0;
+                  reader->in_array = 0;
+                  reader->state = GRPC_JSON_STATE_END;
+                  break;
+                default:
+                  GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
+              }
+            }
+            break;
+
+          default:
+            return GRPC_JSON_PARSE_ERROR;
+        }
+        break;
+
+      /* In-string escaping. */
+      case '\\':
+        switch (reader->state) {
+          case GRPC_JSON_STATE_OBJECT_KEY_STRING:
+            reader->escaped_string_was_key = 1;
+            reader->state = GRPC_JSON_STATE_STRING_ESCAPE;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_STRING:
+            reader->escaped_string_was_key = 0;
+            reader->state = GRPC_JSON_STATE_STRING_ESCAPE;
+            break;
+
+          /* This is the \\ case. */
+          case GRPC_JSON_STATE_STRING_ESCAPE:
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
+            json_reader_string_add_char(reader, '\\');
+            if (reader->escaped_string_was_key) {
+              reader->state = GRPC_JSON_STATE_OBJECT_KEY_STRING;
+            } else {
+              reader->state = GRPC_JSON_STATE_VALUE_STRING;
+            }
+            break;
+
+          default:
+            return GRPC_JSON_PARSE_ERROR;
+        }
+        break;
+
+      default:
+        reader->container_just_begun = 0;
+        switch (reader->state) {
+          case GRPC_JSON_STATE_OBJECT_KEY_BEGIN:
+            if (c != '"') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_OBJECT_KEY_STRING;
+            break;
+
+          case GRPC_JSON_STATE_OBJECT_KEY_STRING:
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
+            if (c == '"') {
+              reader->state = GRPC_JSON_STATE_OBJECT_KEY_END;
+              json_reader_set_key(reader);
+              json_reader_string_clear(reader);
+            } else {
+              if (c < 32) return GRPC_JSON_PARSE_ERROR;
+              json_reader_string_add_char(reader, c);
+            }
+            break;
+
+          case GRPC_JSON_STATE_VALUE_STRING:
+            if (reader->unicode_high_surrogate != 0)
+              return GRPC_JSON_PARSE_ERROR;
+            if (c == '"') {
+              reader->state = GRPC_JSON_STATE_VALUE_END;
+              json_reader_set_string(reader);
+              json_reader_string_clear(reader);
+            } else {
+              if (c < 32) return GRPC_JSON_PARSE_ERROR;
+              json_reader_string_add_char(reader, c);
+            }
+            break;
+
+          case GRPC_JSON_STATE_OBJECT_KEY_END:
+            if (c != ':') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_BEGIN;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_BEGIN:
+            switch (c) {
+              case 't':
+                reader->state = GRPC_JSON_STATE_VALUE_TRUE_R;
+                break;
+
+              case 'f':
+                reader->state = GRPC_JSON_STATE_VALUE_FALSE_A;
+                break;
+
+              case 'n':
+                reader->state = GRPC_JSON_STATE_VALUE_NULL_U;
+                break;
+
+              case '"':
+                reader->state = GRPC_JSON_STATE_VALUE_STRING;
+                break;
+
+              case '0':
+                json_reader_string_add_char(reader, c);
+                reader->state = GRPC_JSON_STATE_VALUE_NUMBER_ZERO;
+                break;
+
+              case '1':
+              case '2':
+              case '3':
+              case '4':
+              case '5':
+              case '6':
+              case '7':
+              case '8':
+              case '9':
+              case '-':
+                json_reader_string_add_char(reader, c);
+                reader->state = GRPC_JSON_STATE_VALUE_NUMBER;
+                break;
+
+              case '{':
+                reader->container_just_begun = 1;
+                json_reader_container_begins(reader, GRPC_JSON_OBJECT);
+                reader->depth++;
+                reader->state = GRPC_JSON_STATE_OBJECT_KEY_BEGIN;
+                reader->in_object = 1;
+                reader->in_array = 0;
+                break;
+
+              case '[':
+                reader->container_just_begun = 1;
+                json_reader_container_begins(reader, GRPC_JSON_ARRAY);
+                reader->depth++;
+                reader->in_object = 0;
+                reader->in_array = 1;
+                break;
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_STRING_ESCAPE:
+            if (reader->escaped_string_was_key) {
+              reader->state = GRPC_JSON_STATE_OBJECT_KEY_STRING;
+            } else {
+              reader->state = GRPC_JSON_STATE_VALUE_STRING;
+            }
+            if (reader->unicode_high_surrogate && c != 'u')
+              return GRPC_JSON_PARSE_ERROR;
+            switch (c) {
+              case '"':
+              case '/':
+                json_reader_string_add_char(reader, c);
+                break;
+              case 'b':
+                json_reader_string_add_char(reader, '\b');
+                break;
+              case 'f':
+                json_reader_string_add_char(reader, '\f');
+                break;
+              case 'n':
+                json_reader_string_add_char(reader, '\n');
+                break;
+              case 'r':
+                json_reader_string_add_char(reader, '\r');
+                break;
+              case 't':
+                json_reader_string_add_char(reader, '\t');
+                break;
+              case 'u':
+                reader->state = GRPC_JSON_STATE_STRING_ESCAPE_U1;
+                reader->unicode_char = 0;
+                break;
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_STRING_ESCAPE_U1:
+          case GRPC_JSON_STATE_STRING_ESCAPE_U2:
+          case GRPC_JSON_STATE_STRING_ESCAPE_U3:
+          case GRPC_JSON_STATE_STRING_ESCAPE_U4:
+            if ((c >= '0') && (c <= '9')) {
+              c -= '0';
+            } else if ((c >= 'A') && (c <= 'F')) {
+              c -= 'A' - 10;
+            } else if ((c >= 'a') && (c <= 'f')) {
+              c -= 'a' - 10;
+            } else {
+              return GRPC_JSON_PARSE_ERROR;
+            }
+            reader->unicode_char = (uint16_t)(reader->unicode_char << 4);
+            reader->unicode_char = (uint16_t)(reader->unicode_char | c);
+
+            switch (reader->state) {
+              case GRPC_JSON_STATE_STRING_ESCAPE_U1:
+                reader->state = GRPC_JSON_STATE_STRING_ESCAPE_U2;
+                break;
+              case GRPC_JSON_STATE_STRING_ESCAPE_U2:
+                reader->state = GRPC_JSON_STATE_STRING_ESCAPE_U3;
+                break;
+              case GRPC_JSON_STATE_STRING_ESCAPE_U3:
+                reader->state = GRPC_JSON_STATE_STRING_ESCAPE_U4;
+                break;
+              case GRPC_JSON_STATE_STRING_ESCAPE_U4:
+                /* See grpc_json_writer_escape_string to have a description
+                 * of what's going on here.
+                 */
+                if ((reader->unicode_char & 0xfc00) == 0xd800) {
+                  /* high surrogate utf-16 */
+                  if (reader->unicode_high_surrogate != 0)
+                    return GRPC_JSON_PARSE_ERROR;
+                  reader->unicode_high_surrogate = reader->unicode_char;
+                } else if ((reader->unicode_char & 0xfc00) == 0xdc00) {
+                  /* low surrogate utf-16 */
+                  uint32_t utf32;
+                  if (reader->unicode_high_surrogate == 0)
+                    return GRPC_JSON_PARSE_ERROR;
+                  utf32 = 0x10000;
+                  utf32 += (uint32_t)(
+                      (reader->unicode_high_surrogate - 0xd800) * 0x400);
+                  utf32 += (uint32_t)(reader->unicode_char - 0xdc00);
+                  json_reader_string_add_utf32(reader, utf32);
+                  reader->unicode_high_surrogate = 0;
+                } else {
+                  /* anything else */
+                  if (reader->unicode_high_surrogate != 0)
+                    return GRPC_JSON_PARSE_ERROR;
+                  json_reader_string_add_utf32(reader, reader->unicode_char);
+                }
+                if (reader->escaped_string_was_key) {
+                  reader->state = GRPC_JSON_STATE_OBJECT_KEY_STRING;
+                } else {
+                  reader->state = GRPC_JSON_STATE_VALUE_STRING;
+                }
+                break;
+              default:
+                GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
+            }
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER:
+            json_reader_string_add_char(reader, c);
+            switch (c) {
+              case '0':
+              case '1':
+              case '2':
+              case '3':
+              case '4':
+              case '5':
+              case '6':
+              case '7':
+              case '8':
+              case '9':
+                break;
+              case 'e':
+              case 'E':
+                reader->state = GRPC_JSON_STATE_VALUE_NUMBER_E;
+                break;
+              case '.':
+                reader->state = GRPC_JSON_STATE_VALUE_NUMBER_DOT;
+                break;
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER_WITH_DECIMAL:
+            json_reader_string_add_char(reader, c);
+            switch (c) {
+              case '0':
+              case '1':
+              case '2':
+              case '3':
+              case '4':
+              case '5':
+              case '6':
+              case '7':
+              case '8':
+              case '9':
+                break;
+              case 'e':
+              case 'E':
+                reader->state = GRPC_JSON_STATE_VALUE_NUMBER_E;
+                break;
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER_ZERO:
+            if (c != '.') return GRPC_JSON_PARSE_ERROR;
+            json_reader_string_add_char(reader, c);
+            reader->state = GRPC_JSON_STATE_VALUE_NUMBER_DOT;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER_DOT:
+            json_reader_string_add_char(reader, c);
+            switch (c) {
+              case '0':
+              case '1':
+              case '2':
+              case '3':
+              case '4':
+              case '5':
+              case '6':
+              case '7':
+              case '8':
+              case '9':
+                reader->state = GRPC_JSON_STATE_VALUE_NUMBER_WITH_DECIMAL;
+                break;
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER_E:
+            json_reader_string_add_char(reader, c);
+            switch (c) {
+              case '0':
+              case '1':
+              case '2':
+              case '3':
+              case '4':
+              case '5':
+              case '6':
+              case '7':
+              case '8':
+              case '9':
+              case '+':
+              case '-':
+                reader->state = GRPC_JSON_STATE_VALUE_NUMBER_EPM;
+                break;
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NUMBER_EPM:
+            json_reader_string_add_char(reader, c);
+            switch (c) {
+              case '0':
+              case '1':
+              case '2':
+              case '3':
+              case '4':
+              case '5':
+              case '6':
+              case '7':
+              case '8':
+              case '9':
+                break;
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_VALUE_TRUE_R:
+            if (c != 'r') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_TRUE_U;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_TRUE_U:
+            if (c != 'u') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_TRUE_E;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_TRUE_E:
+            if (c != 'e') return GRPC_JSON_PARSE_ERROR;
+            json_reader_set_true(reader);
+            reader->state = GRPC_JSON_STATE_VALUE_END;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_FALSE_A:
+            if (c != 'a') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_FALSE_L;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_FALSE_L:
+            if (c != 'l') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_FALSE_S;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_FALSE_S:
+            if (c != 's') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_FALSE_E;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_FALSE_E:
+            if (c != 'e') return GRPC_JSON_PARSE_ERROR;
+            json_reader_set_false(reader);
+            reader->state = GRPC_JSON_STATE_VALUE_END;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NULL_U:
+            if (c != 'u') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_NULL_L1;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NULL_L1:
+            if (c != 'l') return GRPC_JSON_PARSE_ERROR;
+            reader->state = GRPC_JSON_STATE_VALUE_NULL_L2;
+            break;
+
+          case GRPC_JSON_STATE_VALUE_NULL_L2:
+            if (c != 'l') return GRPC_JSON_PARSE_ERROR;
+            json_reader_set_null(reader);
+            reader->state = GRPC_JSON_STATE_VALUE_END;
+            break;
+
+          /* All of the VALUE_END cases are handled in the specialized case
+           * above. */
+          case GRPC_JSON_STATE_VALUE_END:
+            switch (c) {
+              case ',':
+              case '}':
+              case ']':
+                GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
+                break;
+
+              default:
+                return GRPC_JSON_PARSE_ERROR;
+            }
+            break;
+
+          case GRPC_JSON_STATE_END:
+            return GRPC_JSON_PARSE_ERROR;
+        }
+    }
+  }
+
+  GPR_UNREACHABLE_CODE(return GRPC_JSON_INTERNAL_ERROR);
+}
diff --git a/src/core/lib/json/json_reader.h b/src/core/lib/json/json_reader.h
new file mode 100644
index 0000000000..37a838889d
--- /dev/null
+++ b/src/core/lib/json/json_reader.h
@@ -0,0 +1,160 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_JSON_JSON_READER_H
+#define GRPC_CORE_LIB_JSON_JSON_READER_H
+
+#include <grpc/support/port_platform.h>
+#include "src/core/lib/json/json_common.h"
+
+typedef enum {
+  GRPC_JSON_STATE_OBJECT_KEY_BEGIN,
+  GRPC_JSON_STATE_OBJECT_KEY_STRING,
+  GRPC_JSON_STATE_OBJECT_KEY_END,
+  GRPC_JSON_STATE_VALUE_BEGIN,
+  GRPC_JSON_STATE_VALUE_STRING,
+  GRPC_JSON_STATE_STRING_ESCAPE,
+  GRPC_JSON_STATE_STRING_ESCAPE_U1,
+  GRPC_JSON_STATE_STRING_ESCAPE_U2,
+  GRPC_JSON_STATE_STRING_ESCAPE_U3,
+  GRPC_JSON_STATE_STRING_ESCAPE_U4,
+  GRPC_JSON_STATE_VALUE_NUMBER,
+  GRPC_JSON_STATE_VALUE_NUMBER_WITH_DECIMAL,
+  GRPC_JSON_STATE_VALUE_NUMBER_ZERO,
+  GRPC_JSON_STATE_VALUE_NUMBER_DOT,
+  GRPC_JSON_STATE_VALUE_NUMBER_E,
+  GRPC_JSON_STATE_VALUE_NUMBER_EPM,
+  GRPC_JSON_STATE_VALUE_TRUE_R,
+  GRPC_JSON_STATE_VALUE_TRUE_U,
+  GRPC_JSON_STATE_VALUE_TRUE_E,
+  GRPC_JSON_STATE_VALUE_FALSE_A,
+  GRPC_JSON_STATE_VALUE_FALSE_L,
+  GRPC_JSON_STATE_VALUE_FALSE_S,
+  GRPC_JSON_STATE_VALUE_FALSE_E,
+  GRPC_JSON_STATE_VALUE_NULL_U,
+  GRPC_JSON_STATE_VALUE_NULL_L1,
+  GRPC_JSON_STATE_VALUE_NULL_L2,
+  GRPC_JSON_STATE_VALUE_END,
+  GRPC_JSON_STATE_END
+} grpc_json_reader_state;
+
+enum {
+  /* The first non-unicode value is 0x110000. But let's pick
+   * a value high enough to start our error codes from. These
+   * values are safe to return from the read_char function.
+   */
+  GRPC_JSON_READ_CHAR_EOF = 0x7ffffff0,
+  GRPC_JSON_READ_CHAR_EAGAIN,
+  GRPC_JSON_READ_CHAR_ERROR
+};
+
+struct grpc_json_reader;
+
+typedef struct grpc_json_reader_vtable {
+  /* Clears your internal string scratchpad. */
+  void (*string_clear)(void *userdata);
+  /* Adds a char to the string scratchpad. */
+  void (*string_add_char)(void *userdata, uint32_t c);
+  /* Adds a utf32 char to the string scratchpad. */
+  void (*string_add_utf32)(void *userdata, uint32_t c);
+  /* Reads a character from your input. May be utf-8, 16 or 32. */
+  uint32_t (*read_char)(void *userdata);
+  /* Starts a container of type GRPC_JSON_ARRAY or GRPC_JSON_OBJECT. */
+  void (*container_begins)(void *userdata, grpc_json_type type);
+  /* Ends the current container. Must return the type of its parent. */
+  grpc_json_type (*container_ends)(void *userdata);
+  /* Your internal string scratchpad is an object's key. */
+  void (*set_key)(void *userdata);
+  /* Your internal string scratchpad is a string value. */
+  void (*set_string)(void *userdata);
+  /* Your internal string scratchpad is a numerical value. Return 1 if valid. */
+  int (*set_number)(void *userdata);
+  /* Sets the values true, false or null. */
+  void (*set_true)(void *userdata);
+  void (*set_false)(void *userdata);
+  void (*set_null)(void *userdata);
+} grpc_json_reader_vtable;
+
+typedef struct grpc_json_reader {
+  /* That structure is fully private, and initialized by grpc_json_reader_init.
+   * The definition is public so you can put it on your stack.
+   */
+
+  void *userdata;
+  grpc_json_reader_vtable *vtable;
+  int depth;
+  int in_object;
+  int in_array;
+  int escaped_string_was_key;
+  int container_just_begun;
+  uint16_t unicode_char, unicode_high_surrogate;
+  grpc_json_reader_state state;
+} grpc_json_reader;
+
+/* The return type of the parser. */
+typedef enum {
+  GRPC_JSON_DONE,          /* The parser finished successfully. */
+  GRPC_JSON_EAGAIN,        /* The parser yields to get more data. */
+  GRPC_JSON_READ_ERROR,    /* The parser passes through a read error. */
+  GRPC_JSON_PARSE_ERROR,   /* The parser found an error in the json stream. */
+  GRPC_JSON_INTERNAL_ERROR /* The parser got an internal error. */
+} grpc_json_reader_status;
+
+/* Call this function to start parsing the input. It will return the following:
+ *    . GRPC_JSON_DONE if the input got eof, and the parsing finished
+ *      successfully.
+ *    . GRPC_JSON_EAGAIN if the read_char function returned again. Call the
+ *      parser again as needed. It is okay to call the parser in polling mode,
+ *      although a bit dull.
+ *    . GRPC_JSON_READ_ERROR if the read_char function returned an error. The
+ *      state isn't broken however, and the function can be called again if the
+ *      error has been corrected. But please use the EAGAIN feature instead for
+ *      consistency.
+ *    . GRPC_JSON_PARSE_ERROR if the input was somehow invalid.
+ *    . GRPC_JSON_INTERNAL_ERROR if the parser somehow ended into an invalid
+ *      internal state.
+ */
+grpc_json_reader_status grpc_json_reader_run(grpc_json_reader *reader);
+
+/* Call this function to initialize the reader structure. */
+void grpc_json_reader_init(grpc_json_reader *reader,
+                           grpc_json_reader_vtable *vtable, void *userdata);
+
+/* You may call this from the read_char callback if you don't know where is the
+ * end of your input stream, and you'd like the json reader to hint you that it
+ * has completed reading its input, so you can return an EOF to it. Note that
+ * there might still be trailing whitespaces after that point.
+ */
+int grpc_json_reader_is_complete(grpc_json_reader *reader);
+
+#endif /* GRPC_CORE_LIB_JSON_JSON_READER_H */
diff --git a/src/core/lib/json/json_string.c b/src/core/lib/json/json_string.c
new file mode 100644
index 0000000000..8e6f1253dc
--- /dev/null
+++ b/src/core/lib/json/json_string.c
@@ -0,0 +1,379 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/json/json.h"
+#include "src/core/lib/json/json_reader.h"
+#include "src/core/lib/json/json_writer.h"
+
+/* The json reader will construct a bunch of grpc_json objects and
+ * link them all up together in a tree-like structure that will represent
+ * the json data in memory.
+ *
+ * It also uses its own input as a scratchpad to store all of the decoded,
+ * unescaped strings. So we need to keep track of all these pointers in
+ * that opaque structure the reader will carry for us.
+ *
+ * Note that this works because the act of parsing json always reduces its
+ * input size, and never expands it.
+ */
+typedef struct {
+  grpc_json *top;
+  grpc_json *current_container;
+  grpc_json *current_value;
+  uint8_t *input;
+  uint8_t *key;
+  uint8_t *string;
+  uint8_t *string_ptr;
+  size_t remaining_input;
+} json_reader_userdata;
+
+/* This json writer will put everything in a big string.
+ * The point is that we allocate that string in chunks of 256 bytes.
+ */
+typedef struct {
+  char *output;
+  size_t free_space;
+  size_t string_len;
+  size_t allocated;
+} json_writer_userdata;
+
+/* This function checks if there's enough space left in the output buffer,
+ * and will enlarge it if necessary. We're only allocating chunks of 256
+ * bytes at a time (or multiples thereof).
+ */
+static void json_writer_output_check(void *userdata, size_t needed) {
+  json_writer_userdata *state = userdata;
+  if (state->free_space >= needed) return;
+  needed -= state->free_space;
+  /* Round up by 256 bytes. */
+  needed = (needed + 0xff) & ~0xffU;
+  state->output = gpr_realloc(state->output, state->allocated + needed);
+  state->free_space += needed;
+  state->allocated += needed;
+}
+
+/* These are needed by the writer's implementation. */
+static void json_writer_output_char(void *userdata, char c) {
+  json_writer_userdata *state = userdata;
+  json_writer_output_check(userdata, 1);
+  state->output[state->string_len++] = c;
+  state->free_space--;
+}
+
+static void json_writer_output_string_with_len(void *userdata, const char *str,
+                                               size_t len) {
+  json_writer_userdata *state = userdata;
+  json_writer_output_check(userdata, len);
+  memcpy(state->output + state->string_len, str, len);
+  state->string_len += len;
+  state->free_space -= len;
+}
+
+static void json_writer_output_string(void *userdata, const char *str) {
+  size_t len = strlen(str);
+  json_writer_output_string_with_len(userdata, str, len);
+}
+
+/* The reader asks us to clear our scratchpad. In our case, we'll simply mark
+ * the end of the current string, and advance our output pointer.
+ */
+static void json_reader_string_clear(void *userdata) {
+  json_reader_userdata *state = userdata;
+  if (state->string) {
+    GPR_ASSERT(state->string_ptr < state->input);
+    *state->string_ptr++ = 0;
+  }
+  state->string = state->string_ptr;
+}
+
+static void json_reader_string_add_char(void *userdata, uint32_t c) {
+  json_reader_userdata *state = userdata;
+  GPR_ASSERT(state->string_ptr < state->input);
+  GPR_ASSERT(c <= 0xff);
+  *state->string_ptr++ = (uint8_t)c;
+}
+
+/* We are converting a UTF-32 character into UTF-8 here,
+ * as described by RFC3629.
+ */
+static void json_reader_string_add_utf32(void *userdata, uint32_t c) {
+  if (c <= 0x7f) {
+    json_reader_string_add_char(userdata, c);
+  } else if (c <= 0x7ff) {
+    uint32_t b1 = 0xc0 | ((c >> 6) & 0x1f);
+    uint32_t b2 = 0x80 | (c & 0x3f);
+    json_reader_string_add_char(userdata, b1);
+    json_reader_string_add_char(userdata, b2);
+  } else if (c <= 0xffff) {
+    uint32_t b1 = 0xe0 | ((c >> 12) & 0x0f);
+    uint32_t b2 = 0x80 | ((c >> 6) & 0x3f);
+    uint32_t b3 = 0x80 | (c & 0x3f);
+    json_reader_string_add_char(userdata, b1);
+    json_reader_string_add_char(userdata, b2);
+    json_reader_string_add_char(userdata, b3);
+  } else if (c <= 0x1fffff) {
+    uint32_t b1 = 0xf0 | ((c >> 18) & 0x07);
+    uint32_t b2 = 0x80 | ((c >> 12) & 0x3f);
+    uint32_t b3 = 0x80 | ((c >> 6) & 0x3f);
+    uint32_t b4 = 0x80 | (c & 0x3f);
+    json_reader_string_add_char(userdata, b1);
+    json_reader_string_add_char(userdata, b2);
+    json_reader_string_add_char(userdata, b3);
+    json_reader_string_add_char(userdata, b4);
+  }
+}
+
+/* We consider that the input may be a zero-terminated string. So we
+ * can end up hitting eof before the end of the alleged string length.
+ */
+static uint32_t json_reader_read_char(void *userdata) {
+  uint32_t r;
+  json_reader_userdata *state = userdata;
+
+  if (state->remaining_input == 0) return GRPC_JSON_READ_CHAR_EOF;
+
+  r = *state->input++;
+  state->remaining_input--;
+
+  if (r == 0) {
+    state->remaining_input = 0;
+    return GRPC_JSON_READ_CHAR_EOF;
+  }
+
+  return r;
+}
+
+/* Helper function to create a new grpc_json object and link it into
+ * our tree-in-progress inside our opaque structure.
+ */
+static grpc_json *json_create_and_link(void *userdata, grpc_json_type type) {
+  json_reader_userdata *state = userdata;
+  grpc_json *json = grpc_json_create(type);
+
+  json->parent = state->current_container;
+  json->prev = state->current_value;
+  state->current_value = json;
+
+  if (json->prev) {
+    json->prev->next = json;
+  }
+  if (json->parent) {
+    if (!json->parent->child) {
+      json->parent->child = json;
+    }
+    if (json->parent->type == GRPC_JSON_OBJECT) {
+      json->key = (char *)state->key;
+    }
+  }
+  if (!state->top) {
+    state->top = json;
+  }
+
+  return json;
+}
+
+static void json_reader_container_begins(void *userdata, grpc_json_type type) {
+  json_reader_userdata *state = userdata;
+  grpc_json *container;
+
+  GPR_ASSERT(type == GRPC_JSON_ARRAY || type == GRPC_JSON_OBJECT);
+
+  container = json_create_and_link(userdata, type);
+  state->current_container = container;
+  state->current_value = NULL;
+}
+
+/* It's important to remember that the reader is mostly stateless, so it
+ * isn't trying to remember what the container was prior the one that just
+ * ends. Since we're keeping track of these for our own purpose, we are
+ * able to return that information back, which is useful for it to validate
+ * the input json stream.
+ *
+ * Also note that if we're at the top of the tree, and the last container
+ * ends, we have to return GRPC_JSON_TOP_LEVEL.
+ */
+static grpc_json_type json_reader_container_ends(void *userdata) {
+  grpc_json_type container_type = GRPC_JSON_TOP_LEVEL;
+  json_reader_userdata *state = userdata;
+
+  GPR_ASSERT(state->current_container);
+
+  state->current_value = state->current_container;
+  state->current_container = state->current_container->parent;
+
+  if (state->current_container) {
+    container_type = state->current_container->type;
+  }
+
+  return container_type;
+}
+
+/* The next 3 functions basically are the reader asking us to use our string
+ * scratchpad for one of these 3 purposes.
+ *
+ * Note that in the set_number case, we're not going to try interpreting it.
+ * We'll keep it as a string, and leave it to the caller to evaluate it.
+ */
+static void json_reader_set_key(void *userdata) {
+  json_reader_userdata *state = userdata;
+  state->key = state->string;
+}
+
+static void json_reader_set_string(void *userdata) {
+  json_reader_userdata *state = userdata;
+  grpc_json *json = json_create_and_link(userdata, GRPC_JSON_STRING);
+  json->value = (char *)state->string;
+}
+
+static int json_reader_set_number(void *userdata) {
+  json_reader_userdata *state = userdata;
+  grpc_json *json = json_create_and_link(userdata, GRPC_JSON_NUMBER);
+  json->value = (char *)state->string;
+  return 1;
+}
+
+/* The object types true, false and null are self-sufficient, and don't need
+ * any more information beside their type.
+ */
+static void json_reader_set_true(void *userdata) {
+  json_create_and_link(userdata, GRPC_JSON_TRUE);
+}
+
+static void json_reader_set_false(void *userdata) {
+  json_create_and_link(userdata, GRPC_JSON_FALSE);
+}
+
+static void json_reader_set_null(void *userdata) {
+  json_create_and_link(userdata, GRPC_JSON_NULL);
+}
+
+static grpc_json_reader_vtable reader_vtable = {
+    json_reader_string_clear,     json_reader_string_add_char,
+    json_reader_string_add_utf32, json_reader_read_char,
+    json_reader_container_begins, json_reader_container_ends,
+    json_reader_set_key,          json_reader_set_string,
+    json_reader_set_number,       json_reader_set_true,
+    json_reader_set_false,        json_reader_set_null};
+
+/* And finally, let's define our public API. */
+grpc_json *grpc_json_parse_string_with_len(char *input, size_t size) {
+  grpc_json_reader reader;
+  json_reader_userdata state;
+  grpc_json *json = NULL;
+  grpc_json_reader_status status;
+
+  if (!input) return NULL;
+
+  state.top = state.current_container = state.current_value = NULL;
+  state.string = state.key = NULL;
+  state.string_ptr = state.input = (uint8_t *)input;
+  state.remaining_input = size;
+  grpc_json_reader_init(&reader, &reader_vtable, &state);
+
+  status = grpc_json_reader_run(&reader);
+  json = state.top;
+
+  if ((status != GRPC_JSON_DONE) && json) {
+    grpc_json_destroy(json);
+    json = NULL;
+  }
+
+  return json;
+}
+
+#define UNBOUND_JSON_STRING_LENGTH 0x7fffffff
+
+grpc_json *grpc_json_parse_string(char *input) {
+  return grpc_json_parse_string_with_len(input, UNBOUND_JSON_STRING_LENGTH);
+}
+
+static void json_dump_recursive(grpc_json_writer *writer, grpc_json *json,
+                                int in_object) {
+  while (json) {
+    if (in_object) grpc_json_writer_object_key(writer, json->key);
+
+    switch (json->type) {
+      case GRPC_JSON_OBJECT:
+      case GRPC_JSON_ARRAY:
+        grpc_json_writer_container_begins(writer, json->type);
+        if (json->child)
+          json_dump_recursive(writer, json->child,
+                              json->type == GRPC_JSON_OBJECT);
+        grpc_json_writer_container_ends(writer, json->type);
+        break;
+      case GRPC_JSON_STRING:
+        grpc_json_writer_value_string(writer, json->value);
+        break;
+      case GRPC_JSON_NUMBER:
+        grpc_json_writer_value_raw(writer, json->value);
+        break;
+      case GRPC_JSON_TRUE:
+        grpc_json_writer_value_raw_with_len(writer, "true", 4);
+        break;
+      case GRPC_JSON_FALSE:
+        grpc_json_writer_value_raw_with_len(writer, "false", 5);
+        break;
+      case GRPC_JSON_NULL:
+        grpc_json_writer_value_raw_with_len(writer, "null", 4);
+        break;
+      default:
+        GPR_UNREACHABLE_CODE(abort());
+    }
+    json = json->next;
+  }
+}
+
+static grpc_json_writer_vtable writer_vtable = {
+    json_writer_output_char, json_writer_output_string,
+    json_writer_output_string_with_len};
+
+char *grpc_json_dump_to_string(grpc_json *json, int indent) {
+  grpc_json_writer writer;
+  json_writer_userdata state;
+
+  state.output = NULL;
+  state.free_space = state.string_len = state.allocated = 0;
+  grpc_json_writer_init(&writer, indent, &writer_vtable, &state);
+
+  json_dump_recursive(&writer, json, 0);
+
+  json_writer_output_char(&state, 0);
+
+  return state.output;
+}
diff --git a/src/core/lib/json/json_writer.c b/src/core/lib/json/json_writer.c
new file mode 100644
index 0000000000..d614a72fc4
--- /dev/null
+++ b/src/core/lib/json/json_writer.c
@@ -0,0 +1,258 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <string.h>
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/json/json_writer.h"
+
+static void json_writer_output_char(grpc_json_writer *writer, char c) {
+  writer->vtable->output_char(writer->userdata, c);
+}
+
+static void json_writer_output_string(grpc_json_writer *writer,
+                                      const char *str) {
+  writer->vtable->output_string(writer->userdata, str);
+}
+
+static void json_writer_output_string_with_len(grpc_json_writer *writer,
+                                               const char *str, size_t len) {
+  writer->vtable->output_string_with_len(writer->userdata, str, len);
+}
+
+void grpc_json_writer_init(grpc_json_writer *writer, int indent,
+                           grpc_json_writer_vtable *vtable, void *userdata) {
+  memset(writer, 0, sizeof(*writer));
+  writer->container_empty = 1;
+  writer->indent = indent;
+  writer->vtable = vtable;
+  writer->userdata = userdata;
+}
+
+static void json_writer_output_indent(grpc_json_writer *writer) {
+  static const char spacesstr[] =
+      "                "
+      "                "
+      "                "
+      "                ";
+
+  unsigned spaces = (unsigned)(writer->depth * writer->indent);
+
+  if (writer->indent == 0) return;
+
+  if (writer->got_key) {
+    json_writer_output_char(writer, ' ');
+    return;
+  }
+
+  while (spaces >= (sizeof(spacesstr) - 1)) {
+    json_writer_output_string_with_len(writer, spacesstr,
+                                       sizeof(spacesstr) - 1);
+    spaces -= (unsigned)(sizeof(spacesstr) - 1);
+  }
+
+  if (spaces == 0) return;
+
+  json_writer_output_string_with_len(
+      writer, spacesstr + sizeof(spacesstr) - 1 - spaces, spaces);
+}
+
+static void json_writer_value_end(grpc_json_writer *writer) {
+  if (writer->container_empty) {
+    writer->container_empty = 0;
+    if ((writer->indent == 0) || (writer->depth == 0)) return;
+    json_writer_output_char(writer, '\n');
+  } else {
+    json_writer_output_char(writer, ',');
+    if (writer->indent == 0) return;
+    json_writer_output_char(writer, '\n');
+  }
+}
+
+static void json_writer_escape_utf16(grpc_json_writer *writer, uint16_t utf16) {
+  static const char hex[] = "0123456789abcdef";
+
+  json_writer_output_string_with_len(writer, "\\u", 2);
+  json_writer_output_char(writer, hex[(utf16 >> 12) & 0x0f]);
+  json_writer_output_char(writer, hex[(utf16 >> 8) & 0x0f]);
+  json_writer_output_char(writer, hex[(utf16 >> 4) & 0x0f]);
+  json_writer_output_char(writer, hex[(utf16)&0x0f]);
+}
+
+static void json_writer_escape_string(grpc_json_writer *writer,
+                                      const char *string) {
+  json_writer_output_char(writer, '"');
+
+  for (;;) {
+    uint8_t c = (uint8_t)*string++;
+    if (c == 0) {
+      break;
+    } else if ((c >= 32) && (c <= 126)) {
+      if ((c == '\\') || (c == '"')) json_writer_output_char(writer, '\\');
+      json_writer_output_char(writer, (char)c);
+    } else if ((c < 32) || (c == 127)) {
+      switch (c) {
+        case '\b':
+          json_writer_output_string_with_len(writer, "\\b", 2);
+          break;
+        case '\f':
+          json_writer_output_string_with_len(writer, "\\f", 2);
+          break;
+        case '\n':
+          json_writer_output_string_with_len(writer, "\\n", 2);
+          break;
+        case '\r':
+          json_writer_output_string_with_len(writer, "\\r", 2);
+          break;
+        case '\t':
+          json_writer_output_string_with_len(writer, "\\t", 2);
+          break;
+        default:
+          json_writer_escape_utf16(writer, c);
+          break;
+      }
+    } else {
+      uint32_t utf32 = 0;
+      int extra = 0;
+      int i;
+      int valid = 1;
+      if ((c & 0xe0) == 0xc0) {
+        utf32 = c & 0x1f;
+        extra = 1;
+      } else if ((c & 0xf0) == 0xe0) {
+        utf32 = c & 0x0f;
+        extra = 2;
+      } else if ((c & 0xf8) == 0xf0) {
+        utf32 = c & 0x07;
+        extra = 3;
+      } else {
+        break;
+      }
+      for (i = 0; i < extra; i++) {
+        utf32 <<= 6;
+        c = (uint8_t)(*string++);
+        /* Breaks out and bail on any invalid UTF-8 sequence, including \0. */
+        if ((c & 0xc0) != 0x80) {
+          valid = 0;
+          break;
+        }
+        utf32 |= c & 0x3f;
+      }
+      if (!valid) break;
+      /* The range 0xd800 - 0xdfff is reserved by the surrogates ad vitam.
+       * Any other range is technically reserved for future usage, so if we
+       * don't want the software to break in the future, we have to allow
+       * anything else. The first non-unicode character is 0x110000. */
+      if (((utf32 >= 0xd800) && (utf32 <= 0xdfff)) || (utf32 >= 0x110000))
+        break;
+      if (utf32 >= 0x10000) {
+        /* If utf32 contains a character that is above 0xffff, it needs to be
+         * broken down into a utf-16 surrogate pair. A surrogate pair is first
+         * a high surrogate, followed by a low surrogate. Each surrogate holds
+         * 10 bits of usable data, thus allowing a total of 20 bits of data.
+         * The high surrogate marker is 0xd800, while the low surrogate marker
+         * is 0xdc00. The low 10 bits of each will be the usable data.
+         *
+         * After re-combining the 20 bits of data, one has to add 0x10000 to
+         * the resulting value, in order to obtain the original character.
+         * This is obviously because the range 0x0000 - 0xffff can be written
+         * without any special trick.
+         *
+         * Since 0x10ffff is the highest allowed character, we're working in
+         * the range 0x00000 - 0xfffff after we decrement it by 0x10000.
+         * That range is exactly 20 bits.
+         */
+        utf32 -= 0x10000;
+        json_writer_escape_utf16(writer, (uint16_t)(0xd800 | (utf32 >> 10)));
+        json_writer_escape_utf16(writer, (uint16_t)(0xdc00 | (utf32 & 0x3ff)));
+      } else {
+        json_writer_escape_utf16(writer, (uint16_t)utf32);
+      }
+    }
+  }
+
+  json_writer_output_char(writer, '"');
+}
+
+void grpc_json_writer_container_begins(grpc_json_writer *writer,
+                                       grpc_json_type type) {
+  if (!writer->got_key) json_writer_value_end(writer);
+  json_writer_output_indent(writer);
+  json_writer_output_char(writer, type == GRPC_JSON_OBJECT ? '{' : '[');
+  writer->container_empty = 1;
+  writer->got_key = 0;
+  writer->depth++;
+}
+
+void grpc_json_writer_container_ends(grpc_json_writer *writer,
+                                     grpc_json_type type) {
+  if (writer->indent && !writer->container_empty)
+    json_writer_output_char(writer, '\n');
+  writer->depth--;
+  if (!writer->container_empty) json_writer_output_indent(writer);
+  json_writer_output_char(writer, type == GRPC_JSON_OBJECT ? '}' : ']');
+  writer->container_empty = 0;
+  writer->got_key = 0;
+}
+
+void grpc_json_writer_object_key(grpc_json_writer *writer, const char *string) {
+  json_writer_value_end(writer);
+  json_writer_output_indent(writer);
+  json_writer_escape_string(writer, string);
+  json_writer_output_char(writer, ':');
+  writer->got_key = 1;
+}
+
+void grpc_json_writer_value_raw(grpc_json_writer *writer, const char *string) {
+  if (!writer->got_key) json_writer_value_end(writer);
+  json_writer_output_indent(writer);
+  json_writer_output_string(writer, string);
+  writer->got_key = 0;
+}
+
+void grpc_json_writer_value_raw_with_len(grpc_json_writer *writer,
+                                         const char *string, size_t len) {
+  if (!writer->got_key) json_writer_value_end(writer);
+  json_writer_output_indent(writer);
+  json_writer_output_string_with_len(writer, string, len);
+  writer->got_key = 0;
+}
+
+void grpc_json_writer_value_string(grpc_json_writer *writer,
+                                   const char *string) {
+  if (!writer->got_key) json_writer_value_end(writer);
+  json_writer_output_indent(writer);
+  json_writer_escape_string(writer, string);
+  writer->got_key = 0;
+}
diff --git a/src/core/lib/json/json_writer.h b/src/core/lib/json/json_writer.h
new file mode 100644
index 0000000000..f90e79cd74
--- /dev/null
+++ b/src/core/lib/json/json_writer.h
@@ -0,0 +1,97 @@
+/*
+ *
+ * Copyright 2015-2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+/* The idea of the writer is basically symmetrical of the reader. While the
+ * reader emits various calls to your code, the writer takes basically the
+ * same calls and emit json out of it. It doesn't try to make any check on
+ * the order of the calls you do on it. Meaning you can theorically force
+ * it to generate invalid json.
+ *
+ * Also, unlike the reader, the writer expects UTF-8 encoded input strings.
+ * These strings will be UTF-8 validated, and any invalid character will
+ * cut the conversion short, before any invalid UTF-8 sequence, thus forming
+ * a valid UTF-8 string overall.
+ */
+
+#ifndef GRPC_CORE_LIB_JSON_JSON_WRITER_H
+#define GRPC_CORE_LIB_JSON_JSON_WRITER_H
+
+#include <stdlib.h>
+
+#include "src/core/lib/json/json_common.h"
+
+typedef struct grpc_json_writer_vtable {
+  /* Adds a character to the output stream. */
+  void (*output_char)(void *userdata, char);
+  /* Adds a zero-terminated string to the output stream. */
+  void (*output_string)(void *userdata, const char *str);
+  /* Adds a fixed-length string to the output stream. */
+  void (*output_string_with_len)(void *userdata, const char *str, size_t len);
+
+} grpc_json_writer_vtable;
+
+typedef struct grpc_json_writer {
+  void *userdata;
+  grpc_json_writer_vtable *vtable;
+  int indent;
+  int depth;
+  int container_empty;
+  int got_key;
+} grpc_json_writer;
+
+/* Call this to initialize your writer structure. The indent parameter is
+ * specifying the number of spaces to use for indenting the output. If you
+ * use indent=0, then the output will not have any newlines either, thus
+ * emitting a condensed json output.
+ */
+void grpc_json_writer_init(grpc_json_writer *writer, int indent,
+                           grpc_json_writer_vtable *vtable, void *userdata);
+
+/* Signals the beginning of a container. */
+void grpc_json_writer_container_begins(grpc_json_writer *writer,
+                                       grpc_json_type type);
+/* Signals the end of a container. */
+void grpc_json_writer_container_ends(grpc_json_writer *writer,
+                                     grpc_json_type type);
+/* Writes down an object key for the next value. */
+void grpc_json_writer_object_key(grpc_json_writer *writer, const char *string);
+/* Sets a raw value. Useful for numbers. */
+void grpc_json_writer_value_raw(grpc_json_writer *writer, const char *string);
+/* Sets a raw value with its length. Useful for values like true or false. */
+void grpc_json_writer_value_raw_with_len(grpc_json_writer *writer,
+                                         const char *string, size_t len);
+/* Sets a string value. It'll be escaped, and utf-8 validated. */
+void grpc_json_writer_value_string(grpc_json_writer *writer,
+                                   const char *string);
+
+#endif /* GRPC_CORE_LIB_JSON_JSON_WRITER_H */