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Issue 992273002: Random drive-by cleanup. (Closed) Base URL: https://github.com/domokit/mojo.git@master
Patch Set: log seek failures Created 5 years, 9 months ago
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1 // Copyright 2014 The Chromium Authors. All rights reserved. 1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be 2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. 3 // found in the LICENSE file.
4 4
5 #include "shell/application_manager/data_pipe_peek.h" 5 #include "shell/application_manager/data_pipe_peek.h"
6 6
7 #include <stdint.h>
8
7 #include "base/bind.h" 9 #include "base/bind.h"
10 #include "base/macros.h"
8 11
9 namespace mojo { 12 namespace mojo {
10 namespace shell { 13 namespace shell {
11 14
12 namespace { 15 namespace {
13 16
14 // Sleep for as long as max_sleep_micros if the deadline hasn't been reached 17 // Sleep for as long as max_sleep_micros if the deadline hasn't been reached
15 // and the number of bytes read is still increasing. Returns true if sleep 18 // and the number of bytes read is still increasing. Returns true if sleep
16 // was actually called. 19 // was actually called.
17 // 20 //
18 // This class is a substitute for being able to wait until N bytes are available 21 // This class is a substitute for being able to wait until N bytes are available
19 // from a data pipe. The MaybeSleep method is called when num_bytes_read are 22 // from a data pipe. The MaybeSleep method is called when num_bytes_read are
20 // available but more are needed by the Peek operation. If a second 23 // available but more are needed by the Peek operation. If a second
21 // Peek operation finds the same number of bytes after sleeping we assume 24 // Peek operation finds the same number of bytes after sleeping we assume
22 // that there's no point in trying again. 25 // that there's no point in trying again.
23 // TODO(hansmuller): this heuristic is weak. crbug.com/429377 26 // TODO(hansmuller): this heuristic is weak. crbug.com/429377
24 class PeekSleeper { 27 class PeekSleeper {
25 public: 28 public:
26 explicit PeekSleeper(MojoTimeTicks deadline) 29 explicit PeekSleeper(MojoTimeTicks deadline)
27 : deadline_(deadline), 30 : deadline_(deadline),
28 kMaxSleepMicros_(1000 * 10), // 10ms
29 last_number_bytes_read_(0) {} 31 last_number_bytes_read_(0) {}
30 32
31 bool MaybeSleep(uint32 num_bytes_read) { 33 bool MaybeSleep(uint32_t num_bytes_read) {
32 if (num_bytes_read > 0 && last_number_bytes_read_ >= num_bytes_read) 34 if (num_bytes_read > 0 && last_number_bytes_read_ >= num_bytes_read)
33 return false; 35 return false;
34 last_number_bytes_read_ = num_bytes_read; 36 last_number_bytes_read_ = num_bytes_read;
35 37
36 MojoTimeTicks now(GetTimeTicksNow()); 38 MojoTimeTicks now(GetTimeTicksNow());
37 if (now > deadline_) 39 if (now > deadline_)
38 return false; 40 return false;
39 41
40 MojoTimeTicks sleep_time = 42 MojoTimeTicks sleep_time =
41 (deadline_ == 0) 43 (deadline_ == 0) ? kMaxSleepMicros
42 ? kMaxSleepMicros_ 44 : std::min<int64>(deadline_ - now, kMaxSleepMicros);
43 : std::min<int64>(deadline_ - now, PeekSleeper::kMaxSleepMicros_);
44 base::PlatformThread::Sleep(base::TimeDelta::FromMicroseconds(sleep_time)); 45 base::PlatformThread::Sleep(base::TimeDelta::FromMicroseconds(sleep_time));
45 return true; 46 return true;
46 } 47 }
47 48
48 private: 49 private:
50 static const MojoTimeTicks kMaxSleepMicros = 1000 * 10; // 10 ms
51
49 const MojoTimeTicks deadline_; // 0 => MOJO_DEADLINE_INDEFINITE 52 const MojoTimeTicks deadline_; // 0 => MOJO_DEADLINE_INDEFINITE
50 const MojoTimeTicks kMaxSleepMicros_; 53 uint32_t last_number_bytes_read_;
51 uint32 last_number_bytes_read_;
52 54
53 MOJO_DISALLOW_COPY_AND_ASSIGN(PeekSleeper); 55 DISALLOW_COPY_AND_ASSIGN(PeekSleeper);
54 }; 56 };
55 57
58 const MojoTimeTicks PeekSleeper::kMaxSleepMicros;
59
56 enum PeekStatus { kSuccess, kFail, kKeepReading }; 60 enum PeekStatus { kSuccess, kFail, kKeepReading };
57 typedef const base::Callback<PeekStatus(const void*, uint32_t, std::string*)>& 61 typedef const base::Callback<PeekStatus(const void*, uint32_t, std::string*)>&
58 PeekFunc; 62 PeekFunc;
59 63
60 // When data is available on source, call peek_func and then either return true 64 // When data is available on source, call peek_func and then either return true
61 // and value, continue waiting for enough data to satisfy peek_func, or fail 65 // and value, continue waiting for enough data to satisfy peek_func, or fail
62 // and return false. Fail if the timeout is exceeded. 66 // and return false. Fail if the timeout is exceeded.
63 // This function is not guaranteed to work correctly if applied to a data pipe 67 // This function is not guaranteed to work correctly if applied to a data pipe
64 // that's already been read from. 68 // that's already been read from.
65 bool BlockingPeekHelper(DataPipeConsumerHandle source, 69 bool BlockingPeekHelper(DataPipeConsumerHandle source,
(...skipping 35 matching lines...) Expand 10 before | Expand all | Expand 10 after
101 result = 105 result =
102 Wait(source, MOJO_HANDLE_SIGNAL_READABLE, deadline - now, nullptr); 106 Wait(source, MOJO_HANDLE_SIGNAL_READABLE, deadline - now, nullptr);
103 } 107 }
104 } while (result == MOJO_RESULT_OK); 108 } while (result == MOJO_RESULT_OK);
105 109
106 return false; 110 return false;
107 } 111 }
108 112
109 PeekStatus PeekLine(size_t max_line_length, 113 PeekStatus PeekLine(size_t max_line_length,
110 const void* buffer, 114 const void* buffer,
111 uint32 buffer_num_bytes, 115 uint32_t buffer_num_bytes,
112 std::string* line) { 116 std::string* line) {
113 const char* p = static_cast<const char*>(buffer); 117 const char* p = static_cast<const char*>(buffer);
114 size_t max_p_index = std::min<size_t>(buffer_num_bytes, max_line_length); 118 size_t max_p_index = std::min<size_t>(buffer_num_bytes, max_line_length);
115 for (size_t i = 0; i < max_p_index; i++) { 119 for (size_t i = 0; i < max_p_index; i++) {
116 if (p[i] == '\n') { 120 if (p[i] == '\n') {
117 *line = std::string(p, i + 1); // Include the trailing newline. 121 *line = std::string(p, i + 1); // Include the trailing newline.
118 return PeekStatus::kSuccess; 122 return PeekStatus::kSuccess;
119 } 123 }
120 } 124 }
121 return (buffer_num_bytes >= max_line_length) ? PeekStatus::kFail 125 return (buffer_num_bytes >= max_line_length) ? PeekStatus::kFail
122 : PeekStatus::kKeepReading; 126 : PeekStatus::kKeepReading;
123 } 127 }
124 128
125 PeekStatus PeekNBytes(size_t bytes_length, 129 PeekStatus PeekNBytes(size_t bytes_length,
126 const void* buffer, 130 const void* buffer,
127 uint32 buffer_num_bytes, 131 uint32_t buffer_num_bytes,
128 std::string* bytes) { 132 std::string* bytes) {
129 if (buffer_num_bytes >= bytes_length) { 133 if (buffer_num_bytes >= bytes_length) {
130 const char* p = static_cast<const char*>(buffer); 134 const char* p = static_cast<const char*>(buffer);
131 *bytes = std::string(p, bytes_length); 135 *bytes = std::string(p, bytes_length);
132 return PeekStatus::kSuccess; 136 return PeekStatus::kSuccess;
133 } 137 }
134 return PeekStatus::kKeepReading; 138 return PeekStatus::kKeepReading;
135 } 139 }
136 140
137 } // namespace 141 } // namespace
138 142
139 bool BlockingPeekNBytes(DataPipeConsumerHandle source, 143 bool BlockingPeekNBytes(DataPipeConsumerHandle source,
140 std::string* bytes, 144 std::string* bytes,
141 size_t bytes_length, 145 size_t bytes_length,
142 MojoDeadline timeout) { 146 MojoDeadline timeout) {
143 PeekFunc peek_nbytes = base::Bind(PeekNBytes, bytes_length); 147 PeekFunc peek_nbytes = base::Bind(PeekNBytes, bytes_length);
144 return BlockingPeekHelper(source, bytes, timeout, peek_nbytes); 148 return BlockingPeekHelper(source, bytes, timeout, peek_nbytes);
145 } 149 }
146 150
147 bool BlockingPeekLine(DataPipeConsumerHandle source, 151 bool BlockingPeekLine(DataPipeConsumerHandle source,
148 std::string* line, 152 std::string* line,
149 size_t max_line_length, 153 size_t max_line_length,
150 MojoDeadline timeout) { 154 MojoDeadline timeout) {
151 PeekFunc peek_line = base::Bind(PeekLine, max_line_length); 155 PeekFunc peek_line = base::Bind(PeekLine, max_line_length);
152 return BlockingPeekHelper(source, line, timeout, peek_line); 156 return BlockingPeekHelper(source, line, timeout, peek_line);
153 } 157 }
154 158
155 } // namespace shell 159 } // namespace shell
156 } // namespace mojo 160 } // namespace mojo
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