1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc. All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 // * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 // * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 // * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31 // This header is private to the ProtobolBuffers library and must NOT be
32 // included by any sources outside this library. The contents of this file are
33 // subject to change at any time without notice.
34
35 #import "GPBMessage.h"
36
37 #import <libkern/OSAtomic.h>
38
39 #import "GPBBootstrap.h"
40
41 typedef struct GPBMessage_Storage {
42 uint32_t _has_storage_[0];
43 } GPBMessage_Storage;
44
45 typedef struct GPBMessage_Storage *GPBMessage_StoragePtr;
46
GPBMessage()47 @interface GPBMessage () {
48 @package
49 // NOTE: Because of the +allocWithZone code using NSAllocateObject(),
50 // this structure should ideally always be kept pointer aligned where the
51 // real storage starts is also pointer aligned. The compiler/runtime already
52 // do this, but it may not be documented.
53
54 // A pointer to the actual fields of the subclasses. The actual structure
55 // pointed to by this pointer will depend on the subclass.
56 // All of the actual structures will start the same as
57 // GPBMessage_Storage with _has_storage__ as the first field.
58 // Kept public because static functions need to access it.
59 GPBMessage_StoragePtr messageStorage_;
60
61 // A lock to provide mutual exclusion from internal data that can be modified
62 // by *read* operations such as getters (autocreation of message fields and
63 // message extensions, not setting of values). Used to guarantee thread safety
64 // for concurrent reads on the message.
65 // NOTE: OSSpinLock may seem like a good fit here but Apple engineers have
66 // pointed out that they are vulnerable to live locking on iOS in cases of
67 // priority inversion:
68 // http://mjtsai.com/blog/2015/12/16/osspinlock-is-unsafe/
69 // https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20151214/000372.html
70 // Use of readOnlySemaphore_ must be prefaced by a call to
71 // GPBPrepareReadOnlySemaphore to ensure it has been created. This allows
72 // readOnlySemaphore_ to be only created when actually needed.
73 dispatch_once_t readOnlySemaphoreCreationOnce_;
74 dispatch_semaphore_t readOnlySemaphore_;
75 }
76
77 // Gets an extension value without autocreating the result if not found. (i.e.
78 // returns nil if the extension is not set)
79 - (id)getExistingExtension:(GPBExtensionDescriptor *)extension;
80
81 // Parses a message of this type from the input and merges it with this
82 // message.
83 //
84 // Warning: This does not verify that all required fields are present in
85 // the input message.
86 // Note: The caller should call
87 // -[CodedInputStream checkLastTagWas:] after calling this to
88 // verify that the last tag seen was the appropriate end-group tag,
89 // or zero for EOF.
90 // NOTE: This will throw if there is an error while parsing.
91 - (void)mergeFromCodedInputStream:(GPBCodedInputStream *)input
92 extensionRegistry:(GPBExtensionRegistry *)extensionRegistry;
93
94 // Parses the next delimited message of this type from the input and merges it
95 // with this message.
96 - (void)mergeDelimitedFromCodedInputStream:(GPBCodedInputStream *)input
97 extensionRegistry:
98 (GPBExtensionRegistry *)extensionRegistry;
99
100 - (void)addUnknownMapEntry:(int32_t)fieldNum value:(NSData *)data;
101
102 @end
103
104 CF_EXTERN_C_BEGIN
105
106
107 // Call this before using the readOnlySemaphore_. This ensures it is created only once.
GPBPrepareReadOnlySemaphore(GPBMessage * self)108 NS_INLINE void GPBPrepareReadOnlySemaphore(GPBMessage *self) {
109 #pragma clang diagnostic push
110 #pragma clang diagnostic ignored "-Wdirect-ivar-access"
111 dispatch_once(&self->readOnlySemaphoreCreationOnce_, ^{
112 self->readOnlySemaphore_ = dispatch_semaphore_create(1);
113 });
114 #pragma clang diagnostic pop
115 }
116
117 // Returns a new instance that was automatically created by |autocreator| for
118 // its field |field|.
119 GPBMessage *GPBCreateMessageWithAutocreator(Class msgClass,
120 GPBMessage *autocreator,
121 GPBFieldDescriptor *field)
122 __attribute__((ns_returns_retained));
123
124 // Returns whether |message| autocreated this message. This is NO if the message
125 // was not autocreated by |message| or if it has been mutated since
126 // autocreation.
127 BOOL GPBWasMessageAutocreatedBy(GPBMessage *message, GPBMessage *parent);
128
129 // Call this when you mutate a message. It will cause the message to become
130 // visible to its autocreator.
131 void GPBBecomeVisibleToAutocreator(GPBMessage *self);
132
133 // Call this when an array/dictionary is mutated so the parent message that
134 // autocreated it can react.
135 void GPBAutocreatedArrayModified(GPBMessage *self, id array);
136 void GPBAutocreatedDictionaryModified(GPBMessage *self, id dictionary);
137
138 // Clear the autocreator, if any. Asserts if the autocreator still has an
139 // autocreated reference to this message.
140 void GPBClearMessageAutocreator(GPBMessage *self);
141
142 CF_EXTERN_C_END
143