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# Bucket.h

    00001 /*
    00002  *  Phusion Passenger - http://www.modrails.com/
    00003  *  Copyright (c) 2010 Phusion
    00004  *
    00005  *  "Phusion Passenger" is a trademark of Hongli Lai & Ninh Bui.
    00006  *
    00007  *  Permission is hereby granted, free of charge, to any person obtaining a copy
    00008  *  of this software and associated documentation files (the "Software"), to deal
    00009  *  in the Software without restriction, including without limitation the rights
    00010  *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    00011  *  copies of the Software, and to permit persons to whom the Software is
    00012  *  furnished to do so, subject to the following conditions:
    00013  *
    00014  *  The above copyright notice and this permission notice shall be included in
    00015  *  all copies or substantial portions of the Software.
    00016  *
    00017  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    00018  *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    00019  *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    00020  *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    00021  *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    00022  *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    00023  *  THE SOFTWARE.
    00024  */
    00025 #ifndef _PASSENGER_BUCKET_H_
    00026 #define _PASSENGER_BUCKET_H_
    00027
    00028 #include <boost/shared_ptr.hpp>
    00029 #include <apr_buckets.h>
    00030 #include "Session.h"
    00031
    00032 namespace Passenger {
    00033
    00034 using namespace boost;
    00035
    00036 struct PassengerBucketState {
    00037         /** The number of bytes that this PassengerBucket has read so far. */
    00038         unsigned long bytesRead;
    00039
    00040         /** Whether this PassengerBucket is completed, i.e. no more data
    00041          * can be read from the underlying file descriptor. When true,
    00042          * this can either mean that EOF has been reached, or that an I/O
    00043          * error occured. Use errorCode to check whether an error occurred.
    00044          */
    00045         bool completed;
    00046
    00047         /** When completed is true, errorCode contains the errno value of
    00048          * the last read() call.
    00049          *
    00050          * A value of 0 means that no error occured.
    00051          */
    00052         int errorCode;
    00053
    00054         PassengerBucketState() {
    00055                 bytesRead = 0;
    00056                 completed = false;
    00057                 errorCode = 0;
    00058         }
    00059 };
    00060
    00061 typedef shared_ptr<PassengerBucketState> PassengerBucketStatePtr;
    00062
    00063 /**
    00064  * We used to use an apr_bucket_pipe for forwarding the backend process's
    00065  * response to the HTTP client. However, apr_bucket_pipe has a number of
    00066  * issues:
    00067  * - It closes the pipe's file descriptor when it has reached
    00068  *   end-of-stream, but not when an error has occurred. This behavior is
    00069  *   undesirable because it can easily cause file descriptor leaks.
    00070  * - It does weird non-blocking-I/O related things which can cause it
    00071  *   to read less data than can actually be read.
    00072  *
    00073  * PassengerBucket is like apr_bucket_pipe, but:
    00074  * - It also holds a reference to a Session. When a read error has occured
    00075  *   or when end-of-stream has been reached, the Session will be
    00076  *   dereferenced, so that the underlying file descriptor is closed.
    00077  * - It ignores the APR_NONBLOCK_READ flag because that's known to cause
    00078  *   strange I/O problems.
    00079  * - It can store its current state in a PassengerBucketState data structure.
    00080  */
    00081 apr_bucket *passenger_bucket_create(SessionPtr session,
    00082                                     PassengerBucketStatePtr state,
    00083                                     apr_bucket_alloc_t *list);
    00084
    00085 } // namespace Passenger
    00086
    00087 #endif /* _PASSENGER_BUCKET_H_ */