109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
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/*
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* Copyright (C) 2005 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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//
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// FIFO I/O.
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//
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#ifndef _LIBS_UTILS_PIPE_H
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#define _LIBS_UTILS_PIPE_H
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#ifdef HAVE_ANDROID_OS
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#error DO NOT USE THIS FILE IN THE DEVICE BUILD
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#endif
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namespace android {
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/*
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* Simple anonymous unidirectional pipe.
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*
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* The primary goal is to create an implementation with minimal overhead
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* under Linux. Making Windows, Mac OS X, and Linux all work the same way
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* is a secondary goal. Part of this goal is to have something that can
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* be fed to a select() call, so that the application can sleep in the
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* kernel until something interesting happens.
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*/
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class Pipe {
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public:
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Pipe(void);
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virtual ~Pipe(void);
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/* Create the pipe */
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bool create(void);
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/* Create a read-only pipe, using the supplied handle as read handle */
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bool createReader(unsigned long handle);
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/* Create a write-only pipe, using the supplied handle as write handle */
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bool createWriter(unsigned long handle);
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/* Is this object ready to go? */
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bool isCreated(void);
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/*
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* Read "count" bytes from the pipe. Returns the amount of data read,
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* or 0 if no data available and we're non-blocking.
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* Returns -1 on error.
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*/
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int read(void* buf, int count);
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/*
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* Write "count" bytes into the pipe. Returns number of bytes written,
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* or 0 if there's no room for more data and we're non-blocking.
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* Returns -1 on error.
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*/
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int write(const void* buf, int count);
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/* Returns "true" if data is available to read */
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bool readReady(void);
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/* Enable or disable non-blocking I/O for reads */
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bool setReadNonBlocking(bool val);
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/* Enable or disable non-blocking I/O for writes. Only works on Linux. */
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bool setWriteNonBlocking(bool val);
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/*
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* Get the handle. Only useful in some platform-specific situations.
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*/
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unsigned long getReadHandle(void);
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unsigned long getWriteHandle(void);
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/*
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* Modify inheritance, i.e. whether or not a child process will get
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* copies of the descriptors. Systems with fork+exec allow us to close
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* the descriptors before launching the child process, but Win32
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* doesn't allow it.
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*/
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bool disallowReadInherit(void);
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bool disallowWriteInherit(void);
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/*
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* Close one side or the other. Useful in the parent after launching
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* a child process.
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*/
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bool closeRead(void);
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bool closeWrite(void);
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private:
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bool mReadNonBlocking;
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bool mWriteNonBlocking;
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unsigned long mReadHandle;
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unsigned long mWriteHandle;
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};
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}; // android
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#endif // _LIBS_UTILS_PIPE_H
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