1 files changed, 266 insertions, 0 deletions
diff --git a/utils/LocThread.cpp b/utils/LocThread.cpp
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+++ b/utils/LocThread.cpp
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+/* Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ *       copyright notice, this list of conditions and the following
+ *       disclaimer in the documentation and/or other materials provided
+ *       with the distribution.
+ *     * Neither the name of The Linux Foundation, nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+#include <LocThread.h>
+#include <string.h>
+#include <pthread.h>
+#include <loc_pla.h>
+
+class LocThreadDelegate {
+    LocRunnable* mRunnable;
+    bool mJoinable;
+    pthread_t mThandle;
+    pthread_mutex_t mMutex;
+    int mRefCount;
+    ~LocThreadDelegate();
+    LocThreadDelegate(LocThread::tCreate creator, const char* threadName,
+                      LocRunnable* runnable, bool joinable);
+    void destroy();
+public:
+    static LocThreadDelegate* create(LocThread::tCreate creator,
+            const char* threadName, LocRunnable* runnable, bool joinable);
+    void stop();
+    // bye() is for the parent thread to go away. if joinable,
+    // parent must stop the spawned thread, join, and then
+    // destroy(); if detached, the parent can go straight
+    // ahead to destroy()
+    inline void bye() { mJoinable ? stop() : destroy(); }
+    inline bool isRunning() { return (NULL != mRunnable); }
+    static void* threadMain(void* arg);
+};
+
+// it is important to note that internal members must be
+// initialized to values as if pthread_create succeeds.
+// This is to avoid the race condition between the threads,
+// once the thread is created, some of these values will
+// be check in the spawned thread, and must set correctly
+// then and there.
+// However, upon pthread_create failure, the data members
+// must be set to  indicate failure, e.g. mRunnable, and
+// threashold approprietly for destroy(), e.g. mRefCount.
+LocThreadDelegate::LocThreadDelegate(LocThread::tCreate creator,
+        const char* threadName, LocRunnable* runnable, bool joinable) :
+    mRunnable(runnable), mJoinable(joinable), mThandle((pthread_t)NULL),
+    mMutex(PTHREAD_MUTEX_INITIALIZER), mRefCount(2) {
+
+    // set up thread name, if nothing is passed in
+    if (!threadName) {
+        threadName = "LocThread";
+    }
+
+    // create the thread here, then if successful
+    // and a name is given, we set the thread name
+    if (creator) {
+        mThandle = creator(threadName, threadMain, this);
+    } else if (pthread_create(&mThandle, NULL, threadMain, this)) {
+        // pthread_create() failed
+        mThandle = (pthread_t)NULL;
+    }
+
+    if (mThandle) {
+        // set thread name
+        char lname[16];
+        int len = (sizeof(lname) > (strlen(threadName) + 1)) ?
+          (strlen(threadName)):(sizeof(lname) - 1);
+        memcpy(lname, threadName, len);
+        lname[len] = 0;
+        // set the thread name here
+        pthread_setname_np(mThandle, lname);
+
+        // detach, if not joinable
+        if (!joinable) {
+            pthread_detach(mThandle);
+        }
+    } else {
+        // must set these values upon failure
+        mRunnable = NULL;
+        mJoinable = false;
+        mRefCount = 1;
+    }
+}
+
+inline
+LocThreadDelegate::~LocThreadDelegate() {
+    // at this point nothing should need done any more
+}
+
+// factory method so that we could return NULL upon failure
+LocThreadDelegate* LocThreadDelegate::create(LocThread::tCreate creator,
+        const char* threadName, LocRunnable* runnable, bool joinable) {
+    LocThreadDelegate* thread = NULL;
+    if (runnable) {
+        thread = new LocThreadDelegate(creator, threadName, runnable, joinable);
+        if (thread && !thread->isRunning()) {
+            thread->destroy();
+            thread = NULL;
+        }
+    }
+
+    return thread;
+}
+
+// The order is importang
+// NULLing mRunnalbe stops the while loop in threadMain()
+// join() if mJoinble must come before destroy() call, as
+// the obj must remain alive at this time so that mThandle
+// remains valud.
+void LocThreadDelegate::stop() {
+    // mRunnable and mJoinable are reset on different triggers.
+    // mRunnable may get nulled on the spawned thread's way out;
+    //           or here.
+    // mJouinable (if ever been true) gets falsed when client
+    //            thread triggers stop, with either a stop()
+    //            call or the client releases thread obj handle.
+    if (mRunnable) {
+        mRunnable = NULL;
+    }
+    if (mJoinable) {
+        mJoinable = false;
+        pthread_join(mThandle, NULL);
+    }
+    // call destroy() to possibly delete the obj
+    destroy();
+}
+
+// method for clients to call to release the obj
+// when it is a detached thread, the client thread
+// and the spawned thread can both try to destroy()
+// asynchronously. And we delete this obj when
+// mRefCount becomes 0.
+void LocThreadDelegate::destroy() {
+    // else case shouldn't happen, unless there is a
+    // leaking obj. But only our code here has such
+    // obj, so if we test our code well, else case
+    // will never happen
+    if (mRefCount > 0) {
+        // we need a flag on the stack
+        bool callDelete = false;
+
+        // critical section between threads
+        pthread_mutex_lock(&mMutex);
+        // last destroy() call
+        callDelete = (1 == mRefCount--);
+        pthread_mutex_unlock(&mMutex);
+
+        // upon last destroy() call we delete this obj
+        if (callDelete) {
+            delete this;
+        }
+    }
+}
+
+void* LocThreadDelegate::threadMain(void* arg) {
+    LocThreadDelegate* locThread = (LocThreadDelegate*)(arg);
+
+    if (locThread) {
+        LocRunnable* runnable = locThread->mRunnable;
+
+        if (runnable) {
+            if (locThread->isRunning()) {
+                runnable->prerun();
+            }
+
+            while (locThread->isRunning() && runnable->run());
+
+            if (locThread->isRunning()) {
+                runnable->postrun();
+            }
+
+            // at this time, locThread->mRunnable may or may not be NULL
+            // NULL it just to be safe and clean, as we want the field
+            // in the released memory slot to be NULL.
+            locThread->mRunnable = NULL;
+            delete runnable;
+        }
+        locThread->destroy();
+    }
+
+    return NULL;
+}
+
+LocThread::~LocThread() {
+    if (mThread) {
+        mThread->bye();
+        mThread = NULL;
+    }
+}
+
+bool LocThread::start(tCreate creator, const char* threadName, LocRunnable* runnable, bool joinable) {
+    bool success = false;
+    if (!mThread) {
+        mThread = LocThreadDelegate::create(creator, threadName, runnable, joinable);
+        // true only if thread is created successfully
+        success = (NULL != mThread);
+    }
+    return success;
+}
+
+void LocThread::stop() {
+    if (mThread) {
+        mThread->stop();
+        mThread = NULL;
+    }
+}
+
+#ifdef __LOC_DEBUG__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+class LocRunnableTest1 : public LocRunnable {
+    int mID;
+public:
+    LocRunnableTest1(int id) : LocRunnable(), mID(id) {}
+    virtual bool run() {
+        printf("LocRunnableTest1: %d\n", mID++);
+        sleep(1);
+        return true;
+    }
+};
+
+// on linux command line:
+// compile: g++ -D__LOC_HOST_DEBUG__ -D__LOC_DEBUG__ -g -std=c++0x -I. -I../../../../vendor/qcom/proprietary/gps-internal/unit-tests/fakes_for_host -I../../../../system/core/include -lpthread LocThread.cpp
+// test detached thread: valgrind ./a.out 0
+// test joinable thread: valgrind ./a.out 1
+int main(int argc, char** argv) {
+    LocRunnableTest1 test(10);
+
+    LocThread thread;
+    thread.start("LocThreadTest", test, atoi(argv[1]));
+
+    sleep(10);
+
+    thread.stop();
+
+    sleep(5);
+
+    return 0;
+}
+
+#endif