Add new glue code for writing native apps.
This factors out the boiler-plate code from the sample
app to a common glue code that can be used for everyone
writing this style of app: a dedicated app thread that
takes care of waiting for events and processing them.
As part of doing this, ALooper has a new facility to allow
registration of fds that cause ALooper_pollOnce() to return
the fd that has data, allowing the app to drive the loop
without callbacks. Hopefully this makes some people feel better. :)
Also do some other cleanup of the ALooper API, plus some
actual documentation.
Change-Id: Ic53bd56bdf627e3ba28a3c093faa06a92be522b8
diff --git a/include/utils/PollLoop.h b/include/utils/PollLoop.h
index b3651ca..81230e8 100644
--- a/include/utils/PollLoop.h
+++ b/include/utils/PollLoop.h
@@ -42,7 +42,7 @@
virtual ~PollLoop();
public:
- PollLoop();
+ PollLoop(bool allowNonCallbacks);
/**
* A callback that it to be invoked when an event occurs on a file descriptor.
@@ -54,6 +54,12 @@
*/
typedef bool (*Callback)(int fd, int events, void* data);
+ enum {
+ POLL_CALLBACK = ALOOPER_POLL_CALLBACK,
+ POLL_TIMEOUT = ALOOPER_POLL_TIMEOUT,
+ POLL_ERROR = ALOOPER_POLL_ERROR,
+ };
+
/**
* Performs a single call to poll() with optional timeout in milliseconds.
* Invokes callbacks for all file descriptors on which an event occurred.
@@ -61,16 +67,25 @@
* If the timeout is zero, returns immediately without blocking.
* If the timeout is negative, waits indefinitely until awoken.
*
- * Returns true if a callback was invoked or if the loop was awoken by wake().
- * Returns false if a timeout or error occurred.
+ * Returns ALOOPER_POLL_CALLBACK if a callback was invoked.
*
- * This method must only be called on the main thread.
+ * Returns ALOOPER_POLL_TIMEOUT if there was no data before the given
+ * timeout expired.
+ *
+ * Returns ALOPER_POLL_ERROR if an error occurred.
+ *
+ * Returns a value >= 0 containing a file descriptor if it has data
+ * and it has no callback function (requiring the caller here to handle it).
+ * In this (and only this) case outEvents and outData will contain the poll
+ * events and data associated with the fd.
+ *
+ * This method must only be called on the thread owning the PollLoop.
* This method blocks until either a file descriptor is signalled, a timeout occurs,
* or wake() is called.
* This method does not return until it has finished invoking the appropriate callbacks
* for all file descriptors that were signalled.
*/
- bool pollOnce(int timeoutMillis);
+ int32_t pollOnce(int timeoutMillis, int* outEvents = NULL, void** outData = NULL);
/**
* Wakes the loop asynchronously.
@@ -81,6 +96,12 @@
void wake();
/**
+ * Control whether this PollLoop instance allows using IDs instead
+ * of callbacks.
+ */
+ bool getAllowNonCallbacks() const;
+
+ /**
* Sets the callback for a file descriptor, replacing the existing one, if any.
* It is an error to call this method with events == 0 or callback == NULL.
*
@@ -95,7 +116,8 @@
/**
* Like setCallback(), but for the NDK callback function.
*/
- void setLooperCallback(int fd, int events, ALooper_callbackFunc* callback, void* data);
+ void setLooperCallback(int fd, int events, ALooper_callbackFunc* callback,
+ void* data);
/**
* Removes the callback for a file descriptor, if one exists.
@@ -141,7 +163,9 @@
ALooper_callbackFunc* looperCallback;
void* data;
};
-
+
+ const bool mAllowNonCallbacks;
+
Mutex mLock;
bool mPolling;
uint32_t mWaiters;
@@ -155,7 +179,9 @@
Vector<RequestedCallback> mRequestedCallbacks;
Vector<PendingCallback> mPendingCallbacks; // used privately by pollOnce
-
+ Vector<PendingCallback> mPendingFds; // used privately by pollOnce
+ size_t mPendingFdsPos;
+
void openWakePipe();
void closeWakePipe();