NDK media codec sample

Change-Id: Id7e70cfccdace8bce253bdac4434c42f52ff72f3

ndk/platforms/android-20/samples/native-codec/jni/looper.cpp

@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "looper.h"
+
+#include <assert.h>
+#include <jni.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <limits.h>
+#include <semaphore.h>
+
+// for __android_log_print(ANDROID_LOG_INFO, "YourApp", "formatted message");
+#include <android/log.h>
+#define TAG "NativeCodec-looper"
+#define LOGV(...) __android_log_print(ANDROID_LOG_VERBOSE, TAG, __VA_ARGS__)
+
+
+struct loopermessage;
+typedef struct loopermessage loopermessage;
+
+struct loopermessage {
+    int what;
+    void *obj;
+    loopermessage *next;
+    bool quit;
+};
+
+
+
+void* looper::trampoline(void* p) {
+    ((looper*)p)->loop();
+    return NULL;
+}
+
+looper::looper() {
+    sem_init(&headdataavailable, 0, 0);
+    sem_init(&headwriteprotect, 0, 1);
+    pthread_attr_t attr;
+    pthread_attr_init(&attr);
+
+    pthread_create(&worker, &attr, trampoline, this);
+    running = true;
+}
+
+
+looper::~looper() {
+    if (running) {
+        LOGV("Looper deleted while still running. Some messages will not be processed");
+        quit();
+    }
+}
+
+void looper::post(int what, void *data, bool flush) {
+    loopermessage *msg = new loopermessage();
+    msg->what = what;
+    msg->obj = data;
+    msg->next = NULL;
+    msg->quit = false;
+    addmsg(msg, flush);
+}
+
+void looper::addmsg(loopermessage *msg, bool flush) {
+    sem_wait(&headwriteprotect);
+    loopermessage *h = head;
+
+    if (flush) {
+        while(h) {
+            loopermessage *next = h->next;
+            delete h;
+            h = next;
+        }
+        h = NULL;
+    }
+    if (h) {
+        while (h->next) {
+            h = h->next;
+        }
+        h->next = msg;
+    } else {
+        head = msg;
+    }
+    LOGV("post msg %d", msg->what);
+    sem_post(&headwriteprotect);
+    sem_post(&headdataavailable);
+}
+
+void looper::loop() {
+    while(true) {
+        // wait for available message
+        sem_wait(&headdataavailable);
+
+        // get next available message
+        sem_wait(&headwriteprotect);
+        loopermessage *msg = head;
+        if (msg == NULL) {
+            LOGV("no msg");
+            sem_post(&headwriteprotect);
+            continue;
+        }
+        head = msg->next;
+        sem_post(&headwriteprotect);
+
+        if (msg->quit) {
+            LOGV("quitting");
+            delete msg;
+            return;
+        }
+        LOGV("processing msg %d", msg->what);
+        handle(msg->what, msg->obj);
+        delete msg;
+    }
+}
+
+void looper::quit() {
+    LOGV("quit");
+    loopermessage *msg = new loopermessage();
+    msg->what = 0;
+    msg->obj = NULL;
+    msg->next = NULL;
+    msg->quit = true;
+    addmsg(msg, false);
+    void *retval;
+    pthread_join(worker, &retval);
+    sem_destroy(&headdataavailable);
+    sem_destroy(&headwriteprotect);
+    running = false;
+}
+
+void looper::handle(int what, void* obj) {
+    LOGV("dropping msg %d %p", what, obj);
+}
+