1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/netwerk/base/public/nsReadLine.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,134 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + *
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef nsReadLine_h__
1.11 +#define nsReadLine_h__
1.12 +
1.13 +#include "nsIInputStream.h"
1.14 +#include "mozilla/Likely.h"
1.15 +
1.16 +/**
1.17 + * @file
1.18 + * Functions to read complete lines from an input stream.
1.19 + *
1.20 + * To properly use the helper function in here (NS_ReadLine) the caller should
1.21 + * create a nsLineBuffer<T> with new, and pass it to NS_ReadLine every time it
1.22 + * wants a line out.
1.23 + *
1.24 + * When done, the object should be deleted.
1.25 + */
1.26 +
1.27 +/**
1.28 + * @internal
1.29 + * Buffer size. This many bytes will be buffered. If a line is longer than this,
1.30 + * the partial line will be appended to the out parameter of NS_ReadLine and the
1.31 + * buffer will be emptied.
1.32 + * Note: if you change this constant, please update the regression test in
1.33 + * netwerk/test/unit/test_readline.js accordingly (bug 397850).
1.34 + */
1.35 +#define kLineBufferSize 4096
1.36 +
1.37 +/**
1.38 + * @internal
1.39 + * Line buffer structure, buffers data from an input stream.
1.40 + * The buffer is empty when |start| == |end|.
1.41 + * Invariant: |start| <= |end|
1.42 + */
1.43 +template<typename CharT>
1.44 +class nsLineBuffer {
1.45 + public:
1.46 + nsLineBuffer() : start(buf), end(buf) { }
1.47 +
1.48 + CharT buf[kLineBufferSize+1];
1.49 + CharT* start;
1.50 + CharT* end;
1.51 +};
1.52 +
1.53 +/**
1.54 + * Read a line from an input stream. Lines are separated by '\r' (0x0D) or '\n'
1.55 + * (0x0A), or "\r\n" or "\n\r".
1.56 + *
1.57 + * @param aStream
1.58 + * The stream to read from
1.59 + * @param aBuffer
1.60 + * The line buffer to use. A single line buffer must not be used with
1.61 + * different input streams.
1.62 + * @param aLine [out]
1.63 + * The string where the line will be stored.
1.64 + * @param more [out]
1.65 + * Whether more data is available in the buffer. If true, NS_ReadLine may
1.66 + * be called again to read further lines. Otherwise, further calls to
1.67 + * NS_ReadLine will return an error.
1.68 + *
1.69 + * @retval NS_OK
1.70 + * Read successful
1.71 + * @retval error
1.72 + * Input stream returned an error upon read. See
1.73 + * nsIInputStream::read.
1.74 + */
1.75 +template<typename CharT, class StreamType, class StringType>
1.76 +nsresult
1.77 +NS_ReadLine (StreamType* aStream, nsLineBuffer<CharT> * aBuffer,
1.78 + StringType & aLine, bool *more)
1.79 +{
1.80 + CharT eolchar = 0; // the first eol char or 1 after \r\n or \n\r is found
1.81 +
1.82 + aLine.Truncate();
1.83 +
1.84 + while (1) { // will be returning out of this loop on eol or eof
1.85 + if (aBuffer->start == aBuffer->end) { // buffer is empty. Read into it.
1.86 + uint32_t bytesRead;
1.87 + nsresult rv = aStream->Read(aBuffer->buf, kLineBufferSize, &bytesRead);
1.88 + if (NS_FAILED(rv) || MOZ_UNLIKELY(bytesRead == 0)) {
1.89 + *more = false;
1.90 + return rv;
1.91 + }
1.92 + aBuffer->start = aBuffer->buf;
1.93 + aBuffer->end = aBuffer->buf + bytesRead;
1.94 + *(aBuffer->end) = '\0';
1.95 + }
1.96 +
1.97 + /*
1.98 + * Walk the buffer looking for an end-of-line.
1.99 + * There are 3 cases to consider:
1.100 + * 1. the eol char is the last char in the buffer
1.101 + * 2. the eol char + one more char at the end of the buffer
1.102 + * 3. the eol char + two or more chars at the end of the buffer
1.103 + * we need at least one char after the first eol char to determine if
1.104 + * it's a \r\n or \n\r sequence (and skip over it), and we need one
1.105 + * more char after the end-of-line to set |more| correctly.
1.106 + */
1.107 + CharT* current = aBuffer->start;
1.108 + if (MOZ_LIKELY(eolchar == 0)) {
1.109 + for ( ; current < aBuffer->end; ++current) {
1.110 + if (*current == '\n' || *current == '\r') {
1.111 + eolchar = *current;
1.112 + *current++ = '\0';
1.113 + aLine.Append(aBuffer->start);
1.114 + break;
1.115 + }
1.116 + }
1.117 + }
1.118 + if (MOZ_LIKELY(eolchar != 0)) {
1.119 + for ( ; current < aBuffer->end; ++current) {
1.120 + if ((eolchar == '\r' && *current == '\n') ||
1.121 + (eolchar == '\n' && *current == '\r')) {
1.122 + eolchar = 1;
1.123 + continue;
1.124 + }
1.125 + aBuffer->start = current;
1.126 + *more = true;
1.127 + return NS_OK;
1.128 + }
1.129 + }
1.130 +
1.131 + if (eolchar == 0)
1.132 + aLine.Append(aBuffer->start);
1.133 + aBuffer->start = aBuffer->end; // mark the buffer empty
1.134 + }
1.135 +}
1.136 +
1.137 +#endif // nsReadLine_h__
