henrike@webrtc.org | f7795df | 2014-05-13 18:00:26 +0000 | [diff] [blame^] | 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 |