Alpha 1 drop of Google's Objective C plugin and runtime support for protobufs.

.gitignore

@@ -74,3 +74,9 @@ src/**/*.trs
 # JavaBuild output.
 java/target
 javanano/target
+
+# Directories created by opening the Objective C Xcode projects.
+objectivec/ProtocolBuffers_OSX.xcodeproj/project.xcworkspace/xcuserdata/
+objectivec/ProtocolBuffers_OSX.xcodeproj/xcuserdata/
+objectivec/ProtocolBuffers_iOS.xcodeproj/project.xcworkspace/xcuserdata/
+objectivec/ProtocolBuffers_iOS.xcodeproj/xcuserdata/

objectivec/DevTools/check_version_stamps.sh

+#!/bin/bash
+
+# This script checks that the runtime version number constant in the compiler
+# source and in the runtime source is the same.
+#
+# A distro can be made of the protobuf sources with only a subset of the
+# languages, so if the compiler depended on the Objective C runtime, those
+# builds would break. At the same time, we don't want the runtime source
+# depending on the compiler sources; so two copies of the constant are needed.
+
+set -eu
+
+readonly ScriptDir=$(dirname "$(echo $0 | sed -e "s,^\([^/]\),$(pwd)/\1,")")
+readonly ProtoRootDir="${ScriptDir}/../.."
+
+die() {
+    echo "Error: $1"
+    exit 1
+}
+
+readonly ConstantName=GOOGLE_PROTOBUF_OBJC_GEN_VERSION
+
+# Collect version from plugin sources.
+
+readonly PluginSrc="${ProtoRootDir}/src/google/protobuf/compiler/objectivec/objectivec_file.cc"
+readonly PluginVersion=$( \
+    cat "${PluginSrc}" \
+        | sed -n -e "s:const int32_t ${ConstantName} = \([0-9]*\);:\1:p"
+)
+
+if [[ -z "${PluginVersion}" ]] ; then
+    die "Failed to fine ${ConstantName} in the plugin source (${PluginSrc})."
+fi
+
+# Collect version from runtime sources.
+
+readonly RuntimeSrc="${ProtoRootDir}/objectivec/GPBBootstrap.h"
+readonly RuntimeVersion=$( \
+    cat "${RuntimeSrc}" \
+        | sed -n -e "s:#define ${ConstantName} \([0-9]*\):\1:p"
+)
+
+if [[ -z "${RuntimeVersion}" ]] ; then
+    die "Failed to fine ${ConstantName} in the runtime source (${RuntimeSrc})."
+fi
+
+# Compare them.
+
+if [[ "${PluginVersion}" != "${RuntimeVersion}" ]] ; then
+    die "Versions don't match!
+   Plugin: ${PluginVersion} from ${PluginSrc}
+  Runtime: ${RuntimeVersion} from ${RuntimeSrc}
+"
+fi
+
+# Success

objectivec/DevTools/generate_descriptors_proto.sh

+#!/bin/bash
+
+# This script will generate the common descriptors needed by the Objective C
+# runtime.
+
+# HINT:  Flags passed to generate_descriptor_proto.sh will be passed directly
+#   to make when building protoc.  This is particularly useful for passing
+#   -j4 to run 4 jobs simultaneously.
+
+set -eu
+
+readonly ScriptDir=$(dirname "$(echo $0 | sed -e "s,^\([^/]\),$(pwd)/\1,")")
+readonly ProtoRootDir="${ScriptDir}/../.."
+readonly ProtoC="${ProtoRootDir}/src/protoc"
+
+pushd "${ProtoRootDir}" > /dev/null
+
+# Compiler build fails if config.h hasn't been made yet (even if configure/etc.
+# have been run, so get that made first).
+make $@ config.h
+
+# Make sure the compiler is current.
+cd src
+make $@ protoc
+
+# These really should only be run when the inputs or compiler are newer than
+# the outputs.
+
+# Needed by the runtime.
+./protoc --objc_out="${ProtoRootDir}/objectivec" google/protobuf/descriptor.proto
+
+# Well known types that the library provides helpers for.
+./protoc --objc_out="${ProtoRootDir}/objectivec" google/protobuf/timestamp.proto
+./protoc --objc_out="${ProtoRootDir}/objectivec" google/protobuf/duration.proto
+
+popd > /dev/null

objectivec/GPBArray_PackagePrivate.h

+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#import "GPBArray.h"
+
+@class GPBMessage;
+
+//%PDDM-DEFINE DECLARE_ARRAY_EXTRAS()
+//%ARRAY_INTERFACE_EXTRAS(Int32, int32_t)
+//%ARRAY_INTERFACE_EXTRAS(UInt32, uint32_t)
+//%ARRAY_INTERFACE_EXTRAS(Int64, int64_t)
+//%ARRAY_INTERFACE_EXTRAS(UInt64, uint64_t)
+//%ARRAY_INTERFACE_EXTRAS(Float, float)
+//%ARRAY_INTERFACE_EXTRAS(Double, double)
+//%ARRAY_INTERFACE_EXTRAS(Bool, BOOL)
+//%ARRAY_INTERFACE_EXTRAS(Enum, int32_t)
+
+//%PDDM-DEFINE ARRAY_INTERFACE_EXTRAS(NAME, TYPE)
+//%#pragma mark - NAME
+//%
+//%@interface GPB##NAME##Array () {
+//% @package
+//%  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+//%}
+//%@end
+//%
+
+//%PDDM-EXPAND DECLARE_ARRAY_EXTRAS()
+// This block of code is generated, do not edit it directly.
+
+#pragma mark - Int32
+
+@interface GPBInt32Array () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+#pragma mark - UInt32
+
+@interface GPBUInt32Array () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+#pragma mark - Int64
+
+@interface GPBInt64Array () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+#pragma mark - UInt64
+
+@interface GPBUInt64Array () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+#pragma mark - Float
+
+@interface GPBFloatArray () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+#pragma mark - Double
+
+@interface GPBDoubleArray () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+#pragma mark - Bool
+
+@interface GPBBoolArray () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+#pragma mark - Enum
+
+@interface GPBEnumArray () {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end
+
+//%PDDM-EXPAND-END DECLARE_ARRAY_EXTRAS()
+
+#pragma mark - NSArray Subclass
+
+@interface GPBAutocreatedArray : NSMutableArray {
+ @package
+  GPB_UNSAFE_UNRETAINED GPBMessage *_autocreator;
+}
+@end

objectivec/GPBBootstrap.h

+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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 Objective C runtime has complete enough info that most protos don’t end
+// up using this, so leaving it on is no cost or very little cost.  If you
+// happen to see it causing bloat, this is the way to disable it. If you do
+// need to disable it, try only disabling it for Release builds as having
+// full TextFormat can be useful for debugging.
+#ifndef GPBOBJC_SKIP_MESSAGE_TEXTFORMAT_EXTRAS
+#define GPBOBJC_SKIP_MESSAGE_TEXTFORMAT_EXTRAS 0
+#endif
+
+// Most uses of protocol buffers don't need field options, by default the
+// static data will be compiled out, define this to 1 to include it. The only
+// time you need this is if you are doing introspection of the protocol buffers.
+#ifndef GPBOBJC_INCLUDE_FIELD_OPTIONS
+#define GPBOBJC_INCLUDE_FIELD_OPTIONS 0
+#endif
+
+// Used in the generated code to give sizes to enums. int32_t was chosen based
+// on the fact that Protocol Buffers enums are limited to this range.
+// The complexity and double definition here are so we get the nice name
+// for objective C, but also define the name with a trailing underscore so
+// the Swift bridge will have one where the names line up to support short
+// names since they are scoped to the enum.
+// https://developer.apple.com/library/ios/documentation/Swift/Conceptual/BuildingCocoaApps/InteractingWithCAPIs.html#//apple_ref/doc/uid/TP40014216-CH8-XID_11
+#define GPB_ENUM(X) enum X##_ : int32_t X; typedef NS_ENUM(int32_t, X##_)
+// GPB_ENUM_FWD_DECLARE is used for forward declaring enums ex:
+//   GPB_ENUM_FWD_DECLARE(Foo_Enum)
+//   @property (nonatomic) Foo_Enum value;
+#define GPB_ENUM_FWD_DECLARE(_name) enum _name : int32_t
+
+// Based upon CF_INLINE. Forces inlining in release.
+#if !defined(DEBUG)
+#define GPB_INLINE static __inline__ __attribute__((always_inline))
+#else
+#define GPB_INLINE static __inline__
+#endif
+
+// For use in public headers that might need to deal with ARC.
+#ifndef GPB_UNSAFE_UNRETAINED
+#if __has_feature(objc_arc)
+#define GPB_UNSAFE_UNRETAINED __unsafe_unretained
+#else
+#define GPB_UNSAFE_UNRETAINED
+#endif
+#endif
+
+// If property name starts with init we need to annotate it to get past ARC.
+// http://stackoverflow.com/questions/18723226/how-do-i-annotate-an-objective-c-property-with-an-objc-method-family/18723227#18723227
+#define GPB_METHOD_FAMILY_NONE __attribute__((objc_method_family(none)))
+
+// The protoc-gen-objc version which works with the current version of the
+// generated Objective C sources.  In general we don't want to change the
+// runtime interfaces (or this version) as it means everything has to be
+// regenerated.
+#define GOOGLE_PROTOBUF_OBJC_GEN_VERSION 30000

objectivec/GPBCodedInputStream.h

+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#import <Foundation/Foundation.h>
+
+@class GPBMessage;
+@class GPBExtensionRegistry;
+
+// Reads and decodes protocol message fields.
+// Subclassing of GPBCodedInputStream is NOT supported.
+@interface GPBCodedInputStream : NSObject
+
++ (instancetype)streamWithData:(NSData *)data;
+- (instancetype)initWithData:(NSData *)data;
+
+// Attempt to read a field tag, returning zero if we have reached EOF.
+// Protocol message parsers use this to read tags, since a protocol message
+// may legally end wherever a tag occurs, and zero is not a valid tag number.
+- (int32_t)readTag;
+
+- (double)readDouble;
+- (float)readFloat;
+- (uint64_t)readUInt64;
+- (uint32_t)readUInt32;
+- (int64_t)readInt64;
+- (int32_t)readInt32;
+- (uint64_t)readFixed64;
+- (uint32_t)readFixed32;
+- (int32_t)readEnum;
+- (int32_t)readSFixed32;
+- (int64_t)readSFixed64;
+- (int32_t)readSInt32;
+- (int64_t)readSInt64;
+- (BOOL)readBool;
+- (NSString *)readString;
+- (NSData *)readData;
+
+// Read an embedded message field value from the stream.
+- (void)readMessage:(GPBMessage *)message
+    extensionRegistry:(GPBExtensionRegistry *)extensionRegistry;
+
+// Reads and discards a single field, given its tag value.
+- (BOOL)skipField:(int32_t)tag;
+
+// Reads and discards an entire message.  This will read either until EOF
+// or until an endgroup tag, whichever comes first.
+- (void)skipMessage;
+
+// Verifies that the last call to readTag() returned the given tag value.
+// This is used to verify that a nested group ended with the correct
+// end tag.
+- (void)checkLastTagWas:(int32_t)value;
+
+@end

objectivec/GPBCodedInputStream_PackagePrivate.h

+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+// This header is private to the ProtobolBuffers library and must NOT be
+// included by any sources outside this library. The contents of this file are
+// subject to change at any time without notice.
+
+#import "GPBCodedInputStream.h"
+
+#import <libkern/OSAtomic.h>
+
+@class GPBUnknownFieldSet;
+@class GPBFieldDescriptor;
+
+// GPBString is a string subclass that avoids the overhead of initializing
+// a full NSString until it is actually needed. Lots of protocol buffers contain
+// strings, and instantiating all of those strings and having them parsed to
+// verify correctness when the message was being read was expensive, when many
+// of the strings were never being used.
+//
+// Note for future-self. I tried implementing this using a NSProxy.
+// Turned out the performance was horrible in client apps because folks
+// like to use libraries like SBJSON that grab characters one at a time.
+// The proxy overhead was a killer.
+@interface GPBString : NSString
+@end
+
+typedef struct GPBCodedInputStreamState {
+  const uint8_t *bytes;
+  size_t bufferSize;
+  size_t bufferPos;
+
+  // For parsing subsections of an input stream you can put a hard limit on
+  // how much should be read. Normally the limit is the end of the stream,
+  // but you can adjust it to anywhere, and if you hit it you will be at the
+  // end of the stream, until you adjust the limit.
+  size_t currentLimit;
+  int32_t lastTag;
+  NSUInteger recursionDepth;
+} GPBCodedInputStreamState;
+
+@interface GPBCodedInputStream () {
+ @package
+  struct GPBCodedInputStreamState state_;
+  NSData *buffer_;
+}
+
+// Group support is deprecated, so we hide this interface from users, but
+// support for older data.
+- (void)readGroup:(int32_t)fieldNumber
+              message:(GPBMessage *)message
+    extensionRegistry:(GPBExtensionRegistry *)extensionRegistry;
+
+// Reads a group field value from the stream and merges it into the given
+// UnknownFieldSet.
+- (void)readUnknownGroup:(int32_t)fieldNumber
+                 message:(GPBUnknownFieldSet *)message;
+
+// Reads a map entry.
+- (void)readMapEntry:(id)mapDictionary
+    extensionRegistry:(GPBExtensionRegistry *)extensionRegistry
+                field:(GPBFieldDescriptor *)field
+        parentMessage:(GPBMessage *)parentMessage;
+@end
+
+CF_EXTERN_C_BEGIN
+
+// Returns a GPBString with a +1 retain count.
+GPBString *GPBCreateGPBStringWithUTF8(const void *bytes, NSUInteger length)
+    __attribute__((ns_returns_retained));
+
+int32_t GPBCodedInputStreamReadTag(GPBCodedInputStreamState *state);
+
+double GPBCodedInputStreamReadDouble(GPBCodedInputStreamState *state);
+float GPBCodedInputStreamReadFloat(GPBCodedInputStreamState *state);
+uint64_t GPBCodedInputStreamReadUInt64(GPBCodedInputStreamState *state);
+uint32_t GPBCodedInputStreamReadUInt32(GPBCodedInputStreamState *state);
+int64_t GPBCodedInputStreamReadInt64(GPBCodedInputStreamState *state);
+int32_t GPBCodedInputStreamReadInt32(GPBCodedInputStreamState *state);
+uint64_t GPBCodedInputStreamReadFixed64(GPBCodedInputStreamState *state);
+uint32_t GPBCodedInputStreamReadFixed32(GPBCodedInputStreamState *state);
+int32_t GPBCodedInputStreamReadEnum(GPBCodedInputStreamState *state);
+int32_t GPBCodedInputStreamReadSFixed32(GPBCodedInputStreamState *state);
+int64_t GPBCodedInputStreamReadSFixed64(GPBCodedInputStreamState *state);
+int32_t GPBCodedInputStreamReadSInt32(GPBCodedInputStreamState *state);
+int64_t GPBCodedInputStreamReadSInt64(GPBCodedInputStreamState *state);
+BOOL GPBCodedInputStreamReadBool(GPBCodedInputStreamState *state);
+NSString *GPBCodedInputStreamReadRetainedString(GPBCodedInputStreamState *state)
+    __attribute((ns_returns_retained));
+NSData *GPBCodedInputStreamReadRetainedData(GPBCodedInputStreamState *state)
+    __attribute((ns_returns_retained));
+NSData *GPBCodedInputStreamReadRetainedDataNoCopy(
+    GPBCodedInputStreamState *state) __attribute((ns_returns_retained));
+
+size_t GPBCodedInputStreamPushLimit(GPBCodedInputStreamState *state,
+                                    size_t byteLimit);
+void GPBCodedInputStreamPopLimit(GPBCodedInputStreamState *state,
+                                 size_t oldLimit);
+size_t GPBCodedInputStreamBytesUntilLimit(GPBCodedInputStreamState *state);
+BOOL GPBCodedInputStreamIsAtEnd(GPBCodedInputStreamState *state);
+void GPBCodedInputStreamCheckLastTagWas(GPBCodedInputStreamState *state,
+                                        int32_t value);
+
+CF_EXTERN_C_END

objectivec/GPBExtensionField.h

+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#import <Foundation/Foundation.h>
+
+#import "GPBWireFormat.h"
+#import "GPBTypes.h"
+
+@class GPBCodedInputStream;
+@class GPBCodedOutputStream;
+@class GPBExtensionRegistry;
+@class GPBDescriptor;
+@class GPBExtensionDescriptor;
+
+@interface GPBExtensionField : NSObject<NSCopying>
+
+@property(nonatomic, readonly) int32_t fieldNumber;
+@property(nonatomic, readonly) GPBWireFormat wireType;
+@property(nonatomic, readonly) BOOL isRepeated;
+@property(nonatomic, readonly) GPBDescriptor *containingType;
+@property(nonatomic, readonly) id defaultValue;
+@property(nonatomic, readonly) GPBExtensionDescriptor *descriptor;
+
+@end

objectivec/GPBExtensionRegistry.h

+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// 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.
+
+#import <Foundation/Foundation.h>
+
+@class GPBDescriptor;
+@class GPBExtensionField;
+
+// A table of known extensions, searchable by name or field number.  When
+// parsing a protocol message that might have extensions, you must provide an
+// ExtensionRegistry in which you have registered any extensions that you want
+// to be able to parse.  Otherwise, those extensions will just be treated like
+// unknown fields.
+@interface GPBExtensionRegistry : NSObject
+
+- (GPBExtensionField *)getExtension:(GPBDescriptor *)containingType
+                        fieldNumber:(NSInteger)fieldNumber;
+
+@end