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上文中的Socket由frameworks/base/core/java/com/Android/internal/os/ZygoteInit.java文件中的ZygoteInit类在runSelectLoopMode函数侦听的。
Step 5. ZygoteInit.runSelectLoopMode
这个函数定义在frameworks/base/core/java/com/android/internal/os/ZygoteInit.java文件中：
- [java] view plaincopypublic class ZygoteInit {
- ......
- /**
- * Runs the zygote process's select loop. Accepts new connections as
- * they happen, and reads commands from connections one spawn-request's
- * worth at a time.
- *
- * @throws MethodAndArgsCaller in a child process when a main() should
- * be executed.
- */
- private static void runSelectLoopMode() throws MethodAndArgsCaller {
- ArrayList fds = new ArrayList();
- ArrayList peers = new ArrayList();
- FileDescriptor[] fdArray = new FileDescriptor[4];
- fds.add(sServerSocket.getFileDescriptor());
- peers.add(null);
- int loopCount = GC_LOOP_COUNT;
- while (true) {
- int index;
- /*
- * Call gc() before we block in select().
- * It's work that has to be done anyway, and it's better
- * to avoid making every child do it. It will also
- * madvise() any free memory as a side-effect.
- *
- * Don't call it every time, because walking the entire
- * heap is a lot of overhead to free a few hundred bytes.
- */
- if (loopCount <= 0) {
- gc();
- loopCount = GC_LOOP_COUNT;
- } else {
- loopCount--;
- }
- try {
- fdArray = fds.toArray(fdArray);
- index = selectReadable(fdArray);
- } catch (IOException ex) {
- throw new RuntimeException("Error in select()", ex);
- }
- if (index < 0) {
- throw new RuntimeException("Error in select()");
- } else if (index == 0) {
- ZygoteConnection newPeer = acceptCommandPeer();
- peers.add(newPeer);
- fds.add(newPeer.getFileDesciptor());
- } else {
- boolean done;
- done = peers.get(index).runOnce();
- if (done) {
- peers.remove(index);
- fds.remove(index);
- }
- }
- }
- }
- ......
- }
当Step 4将数据通过Socket接口发送出去后，就会下面这个语句：
- [java] view plaincopydone = peers.get(index).runOnce();
这里从peers.get(index)得到的是一个ZygoteConnection对象，表示一个Socket连接，因此，接下来就是调用ZygoteConnection.runOnce函数进一步处理了。