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1 // Copyright 2013 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef MOJO_EDK_SYSTEM_DATA_PIPE_H_ | |
6 #define MOJO_EDK_SYSTEM_DATA_PIPE_H_ | |
7 | |
8 #include <stdint.h> | |
9 | |
10 #include "base/macros.h" | |
11 #include "base/memory/ref_counted.h" | |
12 #include "base/memory/scoped_ptr.h" | |
13 #include "base/synchronization/lock.h" | |
14 #include "mojo/edk/system/handle_signals_state.h" | |
15 #include "mojo/edk/system/memory.h" | |
16 #include "mojo/edk/system/system_impl_export.h" | |
17 #include "mojo/public/c/system/data_pipe.h" | |
18 #include "mojo/public/c/system/types.h" | |
19 | |
20 namespace mojo { | |
21 namespace system { | |
22 | |
23 class Waiter; | |
24 class WaiterList; | |
25 | |
26 // |DataPipe| is a base class for secondary objects implementing data pipes, | |
27 // similar to |MessagePipe| (see the explanatory comment in core.cc). It is | |
28 // typically owned by the dispatcher(s) corresponding to the local endpoints. | |
29 // Its subclasses implement the three cases: local producer and consumer, local | |
30 // producer and remote consumer, and remote producer and local consumer. This | |
31 // class is thread-safe. | |
32 class MOJO_SYSTEM_IMPL_EXPORT DataPipe | |
33 : public base::RefCountedThreadSafe<DataPipe> { | |
34 public: | |
35 // The default options for |MojoCreateDataPipe()|. (Real uses should obtain | |
36 // this via |ValidateCreateOptions()| with a null |in_options|; this is | |
37 // exposed directly for testing convenience.) | |
38 static const MojoCreateDataPipeOptions kDefaultCreateOptions; | |
39 | |
40 // Validates and/or sets default options for |MojoCreateDataPipeOptions|. If | |
41 // non-null, |in_options| must point to a struct of at least | |
42 // |in_options->struct_size| bytes. |out_options| must point to a (current) | |
43 // |MojoCreateDataPipeOptions| and will be entirely overwritten on success (it | |
44 // may be partly overwritten on failure). | |
45 static MojoResult ValidateCreateOptions( | |
46 UserPointer<const MojoCreateDataPipeOptions> in_options, | |
47 MojoCreateDataPipeOptions* out_options); | |
48 | |
49 // These are called by the producer dispatcher to implement its methods of | |
50 // corresponding names. | |
51 void ProducerCancelAllWaiters(); | |
52 void ProducerClose(); | |
53 MojoResult ProducerWriteData(UserPointer<const void> elements, | |
54 UserPointer<uint32_t> num_bytes, | |
55 bool all_or_none); | |
56 MojoResult ProducerBeginWriteData(UserPointer<void*> buffer, | |
57 UserPointer<uint32_t> buffer_num_bytes, | |
58 bool all_or_none); | |
59 MojoResult ProducerEndWriteData(uint32_t num_bytes_written); | |
60 HandleSignalsState ProducerGetHandleSignalsState(); | |
61 MojoResult ProducerAddWaiter(Waiter* waiter, | |
62 MojoHandleSignals signals, | |
63 uint32_t context, | |
64 HandleSignalsState* signals_state); | |
65 void ProducerRemoveWaiter(Waiter* waiter, HandleSignalsState* signals_state); | |
66 bool ProducerIsBusy() const; | |
67 | |
68 // These are called by the consumer dispatcher to implement its methods of | |
69 // corresponding names. | |
70 void ConsumerCancelAllWaiters(); | |
71 void ConsumerClose(); | |
72 // This does not validate its arguments, except to check that |*num_bytes| is | |
73 // a multiple of |element_num_bytes_|. | |
74 MojoResult ConsumerReadData(UserPointer<void> elements, | |
75 UserPointer<uint32_t> num_bytes, | |
76 bool all_or_none); | |
77 MojoResult ConsumerDiscardData(UserPointer<uint32_t> num_bytes, | |
78 bool all_or_none); | |
79 MojoResult ConsumerQueryData(UserPointer<uint32_t> num_bytes); | |
80 MojoResult ConsumerBeginReadData(UserPointer<const void*> buffer, | |
81 UserPointer<uint32_t> buffer_num_bytes, | |
82 bool all_or_none); | |
83 MojoResult ConsumerEndReadData(uint32_t num_bytes_read); | |
84 HandleSignalsState ConsumerGetHandleSignalsState(); | |
85 MojoResult ConsumerAddWaiter(Waiter* waiter, | |
86 MojoHandleSignals signals, | |
87 uint32_t context, | |
88 HandleSignalsState* signals_state); | |
89 void ConsumerRemoveWaiter(Waiter* waiter, HandleSignalsState* signals_state); | |
90 bool ConsumerIsBusy() const; | |
91 | |
92 protected: | |
93 DataPipe(bool has_local_producer, | |
94 bool has_local_consumer, | |
95 const MojoCreateDataPipeOptions& validated_options); | |
96 | |
97 friend class base::RefCountedThreadSafe<DataPipe>; | |
98 virtual ~DataPipe(); | |
99 | |
100 virtual void ProducerCloseImplNoLock() = 0; | |
101 // |num_bytes.Get()| will be a nonzero multiple of |element_num_bytes_|. | |
102 virtual MojoResult ProducerWriteDataImplNoLock( | |
103 UserPointer<const void> elements, | |
104 UserPointer<uint32_t> num_bytes, | |
105 uint32_t max_num_bytes_to_write, | |
106 uint32_t min_num_bytes_to_write) = 0; | |
107 virtual MojoResult ProducerBeginWriteDataImplNoLock( | |
108 UserPointer<void*> buffer, | |
109 UserPointer<uint32_t> buffer_num_bytes, | |
110 uint32_t min_num_bytes_to_write) = 0; | |
111 virtual MojoResult ProducerEndWriteDataImplNoLock( | |
112 uint32_t num_bytes_written) = 0; | |
113 // Note: A producer should not be writable during a two-phase write. | |
114 virtual HandleSignalsState ProducerGetHandleSignalsStateImplNoLock() | |
115 const = 0; | |
116 | |
117 virtual void ConsumerCloseImplNoLock() = 0; | |
118 // |*num_bytes| will be a nonzero multiple of |element_num_bytes_|. | |
119 virtual MojoResult ConsumerReadDataImplNoLock( | |
120 UserPointer<void> elements, | |
121 UserPointer<uint32_t> num_bytes, | |
122 uint32_t max_num_bytes_to_read, | |
123 uint32_t min_num_bytes_to_read) = 0; | |
124 virtual MojoResult ConsumerDiscardDataImplNoLock( | |
125 UserPointer<uint32_t> num_bytes, | |
126 uint32_t max_num_bytes_to_discard, | |
127 uint32_t min_num_bytes_to_discard) = 0; | |
128 // |*num_bytes| will be a nonzero multiple of |element_num_bytes_|. | |
129 virtual MojoResult ConsumerQueryDataImplNoLock( | |
130 UserPointer<uint32_t> num_bytes) = 0; | |
131 virtual MojoResult ConsumerBeginReadDataImplNoLock( | |
132 UserPointer<const void*> buffer, | |
133 UserPointer<uint32_t> buffer_num_bytes, | |
134 uint32_t min_num_bytes_to_read) = 0; | |
135 virtual MojoResult ConsumerEndReadDataImplNoLock(uint32_t num_bytes_read) = 0; | |
136 // Note: A consumer should not be writable during a two-phase read. | |
137 virtual HandleSignalsState ConsumerGetHandleSignalsStateImplNoLock() | |
138 const = 0; | |
139 | |
140 // Thread-safe and fast (they don't take the lock): | |
141 bool may_discard() const { return may_discard_; } | |
142 size_t element_num_bytes() const { return element_num_bytes_; } | |
143 size_t capacity_num_bytes() const { return capacity_num_bytes_; } | |
144 | |
145 // Must be called under lock. | |
146 bool producer_open_no_lock() const { | |
147 lock_.AssertAcquired(); | |
148 return producer_open_; | |
149 } | |
150 bool consumer_open_no_lock() const { | |
151 lock_.AssertAcquired(); | |
152 return consumer_open_; | |
153 } | |
154 uint32_t producer_two_phase_max_num_bytes_written_no_lock() const { | |
155 lock_.AssertAcquired(); | |
156 return producer_two_phase_max_num_bytes_written_; | |
157 } | |
158 uint32_t consumer_two_phase_max_num_bytes_read_no_lock() const { | |
159 lock_.AssertAcquired(); | |
160 return consumer_two_phase_max_num_bytes_read_; | |
161 } | |
162 void set_producer_two_phase_max_num_bytes_written_no_lock( | |
163 uint32_t num_bytes) { | |
164 lock_.AssertAcquired(); | |
165 producer_two_phase_max_num_bytes_written_ = num_bytes; | |
166 } | |
167 void set_consumer_two_phase_max_num_bytes_read_no_lock(uint32_t num_bytes) { | |
168 lock_.AssertAcquired(); | |
169 consumer_two_phase_max_num_bytes_read_ = num_bytes; | |
170 } | |
171 bool producer_in_two_phase_write_no_lock() const { | |
172 lock_.AssertAcquired(); | |
173 return producer_two_phase_max_num_bytes_written_ > 0; | |
174 } | |
175 bool consumer_in_two_phase_read_no_lock() const { | |
176 lock_.AssertAcquired(); | |
177 return consumer_two_phase_max_num_bytes_read_ > 0; | |
178 } | |
179 | |
180 private: | |
181 void AwakeProducerWaitersForStateChangeNoLock( | |
182 const HandleSignalsState& new_producer_state); | |
183 void AwakeConsumerWaitersForStateChangeNoLock( | |
184 const HandleSignalsState& new_consumer_state); | |
185 | |
186 bool has_local_producer_no_lock() const { | |
187 lock_.AssertAcquired(); | |
188 return !!producer_waiter_list_; | |
189 } | |
190 bool has_local_consumer_no_lock() const { | |
191 lock_.AssertAcquired(); | |
192 return !!consumer_waiter_list_; | |
193 } | |
194 | |
195 const bool may_discard_; | |
196 const size_t element_num_bytes_; | |
197 const size_t capacity_num_bytes_; | |
198 | |
199 mutable base::Lock lock_; // Protects the following members. | |
200 // *Known* state of producer or consumer. | |
201 bool producer_open_; | |
202 bool consumer_open_; | |
203 // Non-null only if the producer or consumer, respectively, is local. | |
204 scoped_ptr<WaiterList> producer_waiter_list_; | |
205 scoped_ptr<WaiterList> consumer_waiter_list_; | |
206 // These are nonzero if and only if a two-phase write/read is in progress. | |
207 uint32_t producer_two_phase_max_num_bytes_written_; | |
208 uint32_t consumer_two_phase_max_num_bytes_read_; | |
209 | |
210 DISALLOW_COPY_AND_ASSIGN(DataPipe); | |
211 }; | |
212 | |
213 } // namespace system | |
214 } // namespace mojo | |
215 | |
216 #endif // MOJO_EDK_SYSTEM_DATA_PIPE_H_ | |
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