1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <media/stagefright/foundation/AHierarchicalStateMachine.h> 18 19 #include <media/stagefright/foundation/ADebug.h> 20 #include <media/stagefright/foundation/AMessage.h> 21 #include <utils/Vector.h> 22 23 namespace android { 24 AState(const sp<AState> & parentState)25AState::AState(const sp<AState> &parentState) 26 : mParentState(parentState) { 27 } 28 ~AState()29AState::~AState() { 30 } 31 parentState()32sp<AState> AState::parentState() { 33 return mParentState; 34 } 35 stateEntered()36void AState::stateEntered() { 37 } 38 stateExited()39void AState::stateExited() { 40 } 41 42 //////////////////////////////////////////////////////////////////////////////// 43 AHierarchicalStateMachine()44AHierarchicalStateMachine::AHierarchicalStateMachine() { 45 } 46 ~AHierarchicalStateMachine()47AHierarchicalStateMachine::~AHierarchicalStateMachine() { 48 } 49 onMessageReceived(const sp<AMessage> & msg)50void AHierarchicalStateMachine::onMessageReceived(const sp<AMessage> &msg) { 51 sp<AState> save = mState; 52 53 sp<AState> cur = mState; 54 while (cur != NULL && !cur->onMessageReceived(msg)) { 55 // If you claim not to have handled the message you shouldn't 56 // have called setState... 57 CHECK(save == mState); 58 59 cur = cur->parentState(); 60 } 61 62 if (cur != NULL) { 63 return; 64 } 65 66 ALOGW("Warning message %s unhandled in root state.", 67 msg->debugString().c_str()); 68 } 69 changeState(const sp<AState> & state)70void AHierarchicalStateMachine::changeState(const sp<AState> &state) { 71 if (state == mState) { 72 // Quick exit for the easy case. 73 return; 74 } 75 76 Vector<sp<AState> > A; 77 sp<AState> cur = mState; 78 for (;;) { 79 A.push(cur); 80 if (cur == NULL) { 81 break; 82 } 83 cur = cur->parentState(); 84 } 85 86 Vector<sp<AState> > B; 87 cur = state; 88 for (;;) { 89 B.push(cur); 90 if (cur == NULL) { 91 break; 92 } 93 cur = cur->parentState(); 94 } 95 96 // Remove the common tail. 97 while (A.size() > 0 && B.size() > 0 && A.top() == B.top()) { 98 A.pop(); 99 B.pop(); 100 } 101 102 mState = state; 103 104 for (size_t i = 0; i < A.size(); ++i) { 105 A.editItemAt(i)->stateExited(); 106 } 107 108 for (size_t i = B.size(); i-- > 0;) { 109 B.editItemAt(i)->stateEntered(); 110 } 111 } 112 113 } // namespace android 114