Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/objectivec/GPBRootObject.m

Index: third_party/protobuf/objectivec/GPBRootObject.m
diff --git a/third_party/protobuf/objectivec/GPBRootObject.m b/third_party/protobuf/objectivec/GPBRootObject.m
deleted file mode 100644
index 7036723f56968663822280559a464773e94028cc..0000000000000000000000000000000000000000
--- a/third_party/protobuf/objectivec/GPBRootObject.m
+++ /dev/null
@@ -1,214 +0,0 @@
-// 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 "GPBRootObject_PackagePrivate.h"
-
-#import <objc/runtime.h>
-#import <libkern/OSAtomic.h>
-
-#import <CoreFoundation/CoreFoundation.h>
-
-#import "GPBDescriptor.h"
-#import "GPBExtensionRegistry.h"
-#import "GPBUtilities_PackagePrivate.h"
-
-@interface GPBExtensionDescriptor (GPBRootObject)
-// Get singletonName as a c string.
-- (const char *)singletonNameC;
-@end
-
-@implementation GPBRootObject
-
-// Taken from http://www.burtleburtle.net/bob/hash/doobs.html
-// Public Domain
-static uint32_t jenkins_one_at_a_time_hash(const char *key) {
-  uint32_t hash = 0;
-  for (uint32_t i = 0; key[i] != '\0'; ++i) {
-    hash += key[i];
-    hash += (hash << 10);
-    hash ^= (hash >> 6);
-  }
-  hash += (hash << 3);
-  hash ^= (hash >> 11);
-  hash += (hash << 15);
-  return hash;
-}
-
-// Key methods for our custom CFDictionary.
-// Note that the dictionary lasts for the lifetime of our app, so no need
-// to worry about deallocation. All of the items are added to it at
-// startup, and so the keys don't need to be retained/released.
-// Keys are NULL terminated char *.
-static const void *GPBRootExtensionKeyRetain(CFAllocatorRef allocator,
-                                             const void *value) {
-#pragma unused(allocator)
-  return value;
-}
-
-static void GPBRootExtensionKeyRelease(CFAllocatorRef allocator,
-                                       const void *value) {
-#pragma unused(allocator)
-#pragma unused(value)
-}
-
-static CFStringRef GPBRootExtensionCopyKeyDescription(const void *value) {
-  const char *key = (const char *)value;
-  return CFStringCreateWithCString(kCFAllocatorDefault, key,
-                                   kCFStringEncodingUTF8);
-}
-
-static Boolean GPBRootExtensionKeyEqual(const void *value1,
-                                        const void *value2) {
-  const char *key1 = (const char *)value1;
-  const char *key2 = (const char *)value2;
-  return strcmp(key1, key2) == 0;
-}
-
-static CFHashCode GPBRootExtensionKeyHash(const void *value) {
-  const char *key = (const char *)value;
-  return jenkins_one_at_a_time_hash(key);
-}
-
-static OSSpinLock gExtensionSingletonDictionaryLock_ = OS_SPINLOCK_INIT;
-static CFMutableDictionaryRef gExtensionSingletonDictionary = NULL;
-static GPBExtensionRegistry *gDefaultExtensionRegistry = NULL;
-
-+ (void)initialize {
-  // Ensure the global is started up.
-  if (!gExtensionSingletonDictionary) {
-    CFDictionaryKeyCallBacks keyCallBacks = {
-      // See description above for reason for using custom dictionary.
-      0,
-      GPBRootExtensionKeyRetain,
-      GPBRootExtensionKeyRelease,
-      GPBRootExtensionCopyKeyDescription,
-      GPBRootExtensionKeyEqual,
-      GPBRootExtensionKeyHash,
-    };
-    gExtensionSingletonDictionary =
-        CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &keyCallBacks,
-                                  &kCFTypeDictionaryValueCallBacks);
-    gDefaultExtensionRegistry = [[GPBExtensionRegistry alloc] init];
-  }
-
-  if ([self superclass] == [GPBRootObject class]) {
-    // This is here to start up all the per file "Root" subclasses.
-    // This must be done in initialize to enforce thread safety of start up of
-    // the protocol buffer library.
-    [self extensionRegistry];
-  }
-}
-
-+ (GPBExtensionRegistry *)extensionRegistry {
-  // Is overridden in all the subclasses that provide extensions to provide the
-  // per class one.
-  return gDefaultExtensionRegistry;
-}
-
-+ (void)globallyRegisterExtension:(GPBExtensionDescriptor *)field {
-  const char *key = [field singletonNameC];
-  OSSpinLockLock(&gExtensionSingletonDictionaryLock_);
-  CFDictionarySetValue(gExtensionSingletonDictionary, key, field);
-  OSSpinLockUnlock(&gExtensionSingletonDictionaryLock_);
-}
-
-static id ExtensionForName(id self, SEL _cmd) {
-  // Really fast way of doing "classname_selName".
-  // This came up as a hotspot (creation of NSString *) when accessing a
-  // lot of extensions.
-  const char *selName = sel_getName(_cmd);
-  if (selName[0] == '_') {
-    return nil;  // Apple internal selector.
-  }
-  size_t selNameLen = 0;
-  while (1) {
-    char c = selName[selNameLen];
-    if (c == '\0') {  // String end.
-      break;
-    }
-    if (c == ':') {
-      return nil;  // Selector took an arg, not one of the runtime methods.
-    }
-    ++selNameLen;
-  }
-
-  const char *className = class_getName(self);
-  size_t classNameLen = strlen(className);
-  char key[classNameLen + selNameLen + 2];
-  memcpy(key, className, classNameLen);
-  key[classNameLen] = '_';
-  memcpy(&key[classNameLen + 1], selName, selNameLen);
-  key[classNameLen + 1 + selNameLen] = '\0';
-  OSSpinLockLock(&gExtensionSingletonDictionaryLock_);
-  id extension = (id)CFDictionaryGetValue(gExtensionSingletonDictionary, key);
-  if (extension) {
-    // The method is getting wired in to the class, so no need to keep it in
-    // the dictionary.
-    CFDictionaryRemoveValue(gExtensionSingletonDictionary, key);
-  }
-  OSSpinLockUnlock(&gExtensionSingletonDictionaryLock_);
-  return extension;
-}
-
-BOOL GPBResolveExtensionClassMethod(Class self, SEL sel) {
-  // Another option would be to register the extensions with the class at
-  // globallyRegisterExtension:
-  // Timing the two solutions, this solution turned out to be much faster
-  // and reduced startup time, and runtime memory.
-  // The advantage to globallyRegisterExtension is that it would reduce the
-  // size of the protos somewhat because the singletonNameC wouldn't need
-  // to include the class name. For a class with a lot of extensions it
-  // can add up. You could also significantly reduce the code complexity of this
-  // file.
-  id extension = ExtensionForName(self, sel);
-  if (extension != nil) {
-    const char *encoding =
-        GPBMessageEncodingForSelector(@selector(getClassValue), NO);
-    Class metaClass = objc_getMetaClass(class_getName(self));
-    IMP imp = imp_implementationWithBlock(^(id obj) {
-#pragma unused(obj)
-      return extension;
-    });
-    if (class_addMethod(metaClass, sel, imp, encoding)) {
-      return YES;
-    }
-  }
-  return NO;
-}
-
-
-+ (BOOL)resolveClassMethod:(SEL)sel {
-  if (GPBResolveExtensionClassMethod(self, sel)) {
-    return YES;
-  }
-  return [super resolveClassMethod:sel];
-}
-
-@end