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Merge "Fix typo in comments in looper.h"

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This commit is contained in:
Andrew Hsieh
2014-01-16 17:02:46 +00:00
committed by Gerrit Code Review
parent 6d2d58de54 d980848377
commit 42bb3bcadc
2 changed files with 3 additions and 258 deletions
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256
ndk/platforms/android-13/include/android/looper.h
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@@ -1,256 +0,0 @@
/*
* Copyright (C) 2010 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.
*/
#ifndef ANDROID_LOOPER_H
#define ANDROID_LOOPER_H
#ifdef __cplusplus
extern "C" {
#endif
/**
* ALooper
*
* A looper is the state tracking an event loop for a thread.
* Loopers do not define event structures or other such things; rather
* they are a lower-level facility to attach one or more discrete objects
* listening for an event. An "event" here is simply data available on
* a file descriptor: each attached object has an associated file descriptor,
* and waiting for "events" means (internally) polling on all of these file
* descriptors until one or more of them have data available.
*
* A thread can have only one ALooper associated with it.
*/
struct ALooper;
typedef struct ALooper ALooper;
/**
* Returns the looper associated with the calling thread, or NULL if
* there is not one.
*/
ALooper* ALooper_forThread();
enum {
/**
* Option for ALooper_prepare: this looper will accept calls to
* ALooper_addFd() that do not have a callback (that is provide NULL
* for the callback). In this case the caller of ALooper_pollOnce()
* or ALooper_pollAll() MUST check the return from these functions to
* discover when data is available on such fds and process it.
*/
ALOOPER_PREPARE_ALLOW_NON_CALLBACKS = 1<<0
};
/**
* Prepares a looper associated with the calling thread, and returns it.
* If the thread already has a looper, it is returned. Otherwise, a new
* one is created, associated with the thread, and returned.
*
* The opts may be ALOOPER_PREPARE_ALLOW_NON_CALLBACKS or 0.
*/
ALooper* ALooper_prepare(int opts);
enum {
/**
* Result from ALooper_pollOnce() and ALooper_pollAll():
* The poll was awoken using wake() before the timeout expired
* and no callbacks were executed and no other file descriptors were ready.
*/
ALOOPER_POLL_WAKE = -1,
/**
* Result from ALooper_pollOnce() and ALooper_pollAll():
* One or more callbacks were executed.
*/
ALOOPER_POLL_CALLBACK = -2,
/**
* Result from ALooper_pollOnce() and ALooper_pollAll():
* The timeout expired.
*/
ALOOPER_POLL_TIMEOUT = -3,
/**
* Result from ALooper_pollOnce() and ALooper_pollAll():
* An error occurred.
*/
ALOOPER_POLL_ERROR = -4,
};
/**
* Acquire a reference on the given ALooper object. This prevents the object
* from being deleted until the reference is removed. This is only needed
* to safely hand an ALooper from one thread to another.
*/
void ALooper_acquire(ALooper* looper);
/**
* Remove a reference that was previously acquired with ALooper_acquire().
*/
void ALooper_release(ALooper* looper);
/**
* Flags for file descriptor events that a looper can monitor.
*
* These flag bits can be combined to monitor multiple events at once.
*/
enum {
/**
* The file descriptor is available for read operations.
*/
ALOOPER_EVENT_INPUT = 1 << 0,
/**
* The file descriptor is available for write operations.
*/
ALOOPER_EVENT_OUTPUT = 1 << 1,
/**
* The file descriptor has encountered an error condition.
*
* The looper always sends notifications about errors; it is not necessary
* to specify this event flag in the requested event set.
*/
ALOOPER_EVENT_ERROR = 1 << 2,
/**
* The file descriptor was hung up.
* For example, indicates that the remote end of a pipe or socket was closed.
*
* The looper always sends notifications about hangups; it is not necessary
* to specify this event flag in the requested event set.
*/
ALOOPER_EVENT_HANGUP = 1 << 3,
/**
* The file descriptor is invalid.
* For example, the file descriptor was closed prematurely.
*
* The looper always sends notifications about invalid file descriptors; it is not necessary
* to specify this event flag in the requested event set.
*/
ALOOPER_EVENT_INVALID = 1 << 4,
};
/**
* For callback-based event loops, this is the prototype of the function
* that is called when a file descriptor event occurs.
* It is given the file descriptor it is associated with,
* a bitmask of the poll events that were triggered (typically ALOOPER_EVENT_INPUT),
* and the data pointer that was originally supplied.
*
* Implementations should return 1 to continue receiving callbacks, or 0
* to have this file descriptor and callback unregistered from the looper.
*/
typedef int (*ALooper_callbackFunc)(int fd, int events, void* data);
/**
* Waits for events to be available, with optional timeout in milliseconds.
* Invokes callbacks for all file descriptors on which an event occurred.
*
* If the timeout is zero, returns immediately without blocking.
* If the timeout is negative, waits indefinitely until an event appears.
*
* Returns ALOOPER_POLL_WAKE if the poll was awoken using wake() before
* the timeout expired and no callbacks were invoked and no other file
* descriptors were ready.
*
* Returns ALOOPER_POLL_CALLBACK if one or more callbacks were invoked.
*
* Returns ALOOPER_POLL_TIMEOUT if there was no data before the given
* timeout expired.
*
* Returns ALOOPER_POLL_ERROR if an error occurred.
*
* Returns a value >= 0 containing an identifier if its file descriptor has data
* and it has no callback function (requiring the caller here to handle it).
* In this (and only this) case outFd, outEvents and outData will contain the poll
* events and data associated with the fd, otherwise they will be set to NULL.
*
* This method does not return until it has finished invoking the appropriate callbacks
* for all file descriptors that were signalled.
*/
int ALooper_pollOnce(int timeoutMillis, int* outFd, int* outEvents, void** outData);
/**
* Like ALooper_pollOnce(), but performs all pending callbacks until all
* data has been consumed or a file descriptor is available with no callback.
* This function will never return ALOOPER_POLL_CALLBACK.
*/
int ALooper_pollAll(int timeoutMillis, int* outFd, int* outEvents, void** outData);
/**
* Wakes the poll asynchronously.
*
* This method can be called on any thread.
* This method returns immediately.
*/
void ALooper_wake(ALooper* looper);
/**
* Adds a new file descriptor to be polled by the looper.
* If the same file descriptor was previously added, it is replaced.
*
* "fd" is the file descriptor to be added.
* "ident" is an identifier for this event, which is returned from ALooper_pollOnce().
* The identifier must be >= 0, or ALOOPER_POLL_CALLBACK if providing a non-NULL callback.
* "events" are the poll events to wake up on. Typically this is ALOOPER_EVENT_INPUT.
* "callback" is the function to call when there is an event on the file descriptor.
* "data" is a private data pointer to supply to the callback.
*
* There are two main uses of this function:
*
* (1) If "callback" is non-NULL, then this function will be called when there is
* data on the file descriptor. It should execute any events it has pending,
* appropriately reading from the file descriptor. The 'ident' is ignored in this case.
*
* (2) If "callback" is NULL, the 'ident' will be returned by ALooper_pollOnce
* when its file descriptor has data available, requiring the caller to take
* care of processing it.
*
* Returns 1 if the file descriptor was added or -1 if an error occurred.
*
* This method can be called on any thread.
* This method may block briefly if it needs to wake the poll.
*/
int ALooper_addFd(ALooper* looper, int fd, int ident, int events,
ALooper_callbackFunc callback, void* data);
/**
* Removes a previously added file descriptor from the looper.
*
* When this method returns, it is safe to close the file descriptor since the looper
* will no longer have a reference to it. However, it is possible for the callback to
* already be running or for it to run one last time if the file descriptor was already
* signalled. Calling code is responsible for ensuring that this case is safely handled.
* For example, if the callback takes care of removing itself during its own execution either
* by returning 0 or by calling this method, then it can be guaranteed to not be invoked
* again at any later time unless registered anew.
*
* Returns 1 if the file descriptor was removed, 0 if none was previously registered
* or -1 if an error occurred.
*
* This method can be called on any thread.
* This method may block briefly if it needs to wake the poll.
*/
int ALooper_removeFd(ALooper* looper, int fd);
#ifdef __cplusplus
};
#endif
#endif // ANDROID_NATIVE_WINDOW_H

5
ndk/platforms/android-9/include/android/looper.h
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@@ -148,7 +148,8 @@ enum {
/** /**
* For callback-based event loops, this is the prototype of the function * For callback-based event loops, this is the prototype of the function
* that is called. It is given the file descriptor it is associated with, * that is called when a file descriptor event occurs.
* It is given the file descriptor it is associated with,
* a bitmask of the poll events that were triggered (typically ALOOPER_EVENT_INPUT), * a bitmask of the poll events that were triggered (typically ALOOPER_EVENT_INPUT),
* and the data pointer that was originally supplied. * and the data pointer that was originally supplied.
* *
@@ -252,4 +253,4 @@ int ALooper_removeFd(ALooper* looper, int fd);
}; };
#endif #endif
#endif // ANDROID_NATIVE_WINDOW_H #endif // ANDROID_LOOPER_H