1 /* 2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "webrtc/base/task.h" 12 #include "webrtc/base/common.h" 13 #include "webrtc/base/taskrunner.h" 14 15 namespace rtc { 16 17 int32 Task::unique_id_seed_ = 0; 18 19 Task::Task(TaskParent *parent) 20 : TaskParent(this, parent), 21 state_(STATE_INIT), 22 blocked_(false), 23 done_(false), 24 aborted_(false), 25 busy_(false), 26 error_(false), 27 start_time_(0), 28 timeout_time_(0), 29 timeout_seconds_(0), 30 timeout_suspended_(false) { 31 unique_id_ = unique_id_seed_++; 32 33 // sanity check that we didn't roll-over our id seed 34 ASSERT(unique_id_ < unique_id_seed_); 35 } 36 37 Task::~Task() { 38 // Is this task being deleted in the correct manner? 39 ASSERT(!done_ || GetRunner()->is_ok_to_delete(this)); 40 ASSERT(state_ == STATE_INIT || done_); 41 ASSERT(state_ == STATE_INIT || blocked_); 42 43 // If the task is being deleted without being done, it 44 // means that it hasn't been removed from its parent. 45 // This happens if a task is deleted outside of TaskRunner. 46 if (!done_) { 47 Stop(); 48 } 49 } 50 51 int64 Task::CurrentTime() { 52 return GetRunner()->CurrentTime(); 53 } 54 55 int64 Task::ElapsedTime() { 56 return CurrentTime() - start_time_; 57 } 58 59 void Task::Start() { 60 if (state_ != STATE_INIT) 61 return; 62 // Set the start time before starting the task. Otherwise if the task 63 // finishes quickly and deletes the Task object, setting start_time_ 64 // will crash. 65 start_time_ = CurrentTime(); 66 GetRunner()->StartTask(this); 67 } 68 69 void Task::Step() { 70 if (done_) { 71 #ifdef _DEBUG 72 // we do not know how !blocked_ happens when done_ - should be impossible. 73 // But it causes problems, so in retail build, we force blocked_, and 74 // under debug we assert. 75 ASSERT(blocked_); 76 #else 77 blocked_ = true; 78 #endif 79 return; 80 } 81 82 // Async Error() was called 83 if (error_) { 84 done_ = true; 85 state_ = STATE_ERROR; 86 blocked_ = true; 87 // obsolete - an errored task is not considered done now 88 // SignalDone(); 89 90 Stop(); 91 #ifdef _DEBUG 92 // verify that stop removed this from its parent 93 ASSERT(!parent()->IsChildTask(this)); 94 #endif 95 return; 96 } 97 98 busy_ = true; 99 int new_state = Process(state_); 100 busy_ = false; 101 102 if (aborted_) { 103 Abort(true); // no need to wake because we're awake 104 return; 105 } 106 107 if (new_state == STATE_BLOCKED) { 108 blocked_ = true; 109 // Let the timeout continue 110 } else { 111 state_ = new_state; 112 blocked_ = false; 113 ResetTimeout(); 114 } 115 116 if (new_state == STATE_DONE) { 117 done_ = true; 118 } else if (new_state == STATE_ERROR) { 119 done_ = true; 120 error_ = true; 121 } 122 123 if (done_) { 124 // obsolete - call this yourself 125 // SignalDone(); 126 127 Stop(); 128 #if _DEBUG 129 // verify that stop removed this from its parent 130 ASSERT(!parent()->IsChildTask(this)); 131 #endif 132 blocked_ = true; 133 } 134 } 135 136 void Task::Abort(bool nowake) { 137 // Why only check for done_ (instead of "aborted_ || done_")? 138 // 139 // If aborted_ && !done_, it means the logic for aborting still 140 // needs to be executed (because busy_ must have been true when 141 // Abort() was previously called). 142 if (done_) 143 return; 144 aborted_ = true; 145 if (!busy_) { 146 done_ = true; 147 blocked_ = true; 148 error_ = true; 149 150 // "done_" is set before calling "Stop()" to ensure that this code 151 // doesn't execute more than once (recursively) for the same task. 152 Stop(); 153 #ifdef _DEBUG 154 // verify that stop removed this from its parent 155 ASSERT(!parent()->IsChildTask(this)); 156 #endif 157 if (!nowake) { 158 // WakeTasks to self-delete. 159 // Don't call Wake() because it is a no-op after "done_" is set. 160 // Even if Wake() did run, it clears "blocked_" which isn't desireable. 161 GetRunner()->WakeTasks(); 162 } 163 } 164 } 165 166 void Task::Wake() { 167 if (done_) 168 return; 169 if (blocked_) { 170 blocked_ = false; 171 GetRunner()->WakeTasks(); 172 } 173 } 174 175 void Task::Error() { 176 if (error_ || done_) 177 return; 178 error_ = true; 179 Wake(); 180 } 181 182 std::string Task::GetStateName(int state) const { 183 switch (state) { 184 case STATE_BLOCKED: return "BLOCKED"; 185 case STATE_INIT: return "INIT"; 186 case STATE_START: return "START"; 187 case STATE_DONE: return "DONE"; 188 case STATE_ERROR: return "ERROR"; 189 case STATE_RESPONSE: return "RESPONSE"; 190 } 191 return "??"; 192 } 193 194 int Task::Process(int state) { 195 int newstate = STATE_ERROR; 196 197 if (TimedOut()) { 198 ClearTimeout(); 199 newstate = OnTimeout(); 200 SignalTimeout(); 201 } else { 202 switch (state) { 203 case STATE_INIT: 204 newstate = STATE_START; 205 break; 206 case STATE_START: 207 newstate = ProcessStart(); 208 break; 209 case STATE_RESPONSE: 210 newstate = ProcessResponse(); 211 break; 212 case STATE_DONE: 213 case STATE_ERROR: 214 newstate = STATE_BLOCKED; 215 break; 216 } 217 } 218 219 return newstate; 220 } 221 222 void Task::Stop() { 223 // No need to wake because we're either awake or in abort 224 TaskParent::OnStopped(this); 225 } 226 227 void Task::set_timeout_seconds(const int timeout_seconds) { 228 timeout_seconds_ = timeout_seconds; 229 ResetTimeout(); 230 } 231 232 bool Task::TimedOut() { 233 return timeout_seconds_ && 234 timeout_time_ && 235 CurrentTime() >= timeout_time_; 236 } 237 238 void Task::ResetTimeout() { 239 int64 previous_timeout_time = timeout_time_; 240 bool timeout_allowed = (state_ != STATE_INIT) 241 && (state_ != STATE_DONE) 242 && (state_ != STATE_ERROR); 243 if (timeout_seconds_ && timeout_allowed && !timeout_suspended_) 244 timeout_time_ = CurrentTime() + 245 (timeout_seconds_ * kSecToMsec * kMsecTo100ns); 246 else 247 timeout_time_ = 0; 248 249 GetRunner()->UpdateTaskTimeout(this, previous_timeout_time); 250 } 251 252 void Task::ClearTimeout() { 253 int64 previous_timeout_time = timeout_time_; 254 timeout_time_ = 0; 255 GetRunner()->UpdateTaskTimeout(this, previous_timeout_time); 256 } 257 258 void Task::SuspendTimeout() { 259 if (!timeout_suspended_) { 260 timeout_suspended_ = true; 261 ResetTimeout(); 262 } 263 } 264 265 void Task::ResumeTimeout() { 266 if (timeout_suspended_) { 267 timeout_suspended_ = false; 268 ResetTimeout(); 269 } 270 } 271 272 } // namespace rtc 273