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 //#define LOG_NDEBUG 0 18 #define LOG_TAG "AHierarchicalStateMachine" 19 #include <utils/Log.h> 20 21 #include <media/stagefright/foundation/AHierarchicalStateMachine.h> 22 23 #include <media/stagefright/foundation/ADebug.h> 24 #include <media/stagefright/foundation/AMessage.h> 25 #include <utils/Vector.h> 26 27 namespace android { 28 29 AState::AState(const sp<AState> &parentState) 30 : mParentState(parentState) { 31 } 32 33 AState::~AState() { 34 } 35 36 sp<AState> AState::parentState() { 37 return mParentState; 38 } 39 40 void AState::stateEntered() { 41 } 42 43 void AState::stateExited() { 44 } 45 46 //////////////////////////////////////////////////////////////////////////////// 47 48 AHierarchicalStateMachine::AHierarchicalStateMachine() { 49 } 50 51 AHierarchicalStateMachine::~AHierarchicalStateMachine() { 52 } 53 54 void AHierarchicalStateMachine::handleMessage(const sp<AMessage> &msg) { 55 sp<AState> save = mState; 56 57 sp<AState> cur = mState; 58 while (cur != NULL && !cur->onMessageReceived(msg)) { 59 // If you claim not to have handled the message you shouldn't 60 // have called setState... 61 CHECK(save == mState); 62 63 cur = cur->parentState(); 64 } 65 66 if (cur != NULL) { 67 return; 68 } 69 70 ALOGW("Warning message %s unhandled in root state.", 71 msg->debugString().c_str()); 72 } 73 74 void AHierarchicalStateMachine::changeState(const sp<AState> &state) { 75 if (state == mState) { 76 // Quick exit for the easy case. 77 return; 78 } 79 80 Vector<sp<AState> > A; 81 sp<AState> cur = mState; 82 for (;;) { 83 A.push(cur); 84 if (cur == NULL) { 85 break; 86 } 87 cur = cur->parentState(); 88 } 89 90 Vector<sp<AState> > B; 91 cur = state; 92 for (;;) { 93 B.push(cur); 94 if (cur == NULL) { 95 break; 96 } 97 cur = cur->parentState(); 98 } 99 100 // Remove the common tail. 101 while (A.size() > 0 && B.size() > 0 && A.top() == B.top()) { 102 A.pop(); 103 B.pop(); 104 } 105 106 mState = state; 107 108 for (size_t i = 0; i < A.size(); ++i) { 109 A.editItemAt(i)->stateExited(); 110 } 111 112 for (size_t i = B.size(); i > 0;) { 113 i--; 114 B.editItemAt(i)->stateEntered(); 115 } 116 } 117 118 } // namespace android 119