From d569c0e9112fd85d2741695d88be92a30e8a9587 Mon Sep 17 00:00:00 2001 From: "mats.palmgren@bredband.net" Date: Wed, 9 Jan 2008 22:17:29 -0800 Subject: [PATCH] Make NS_ReadLine() not lie about having more data when the stream ends in \r\n. b=397850 r+sr=cbiesinger a=blocking1.9 --- netwerk/base/public/nsReadLine.h | 118 ++++++++++++++----------------- 1 file changed, 53 insertions(+), 65 deletions(-) diff --git a/netwerk/base/public/nsReadLine.h b/netwerk/base/public/nsReadLine.h index fb6d7a94349..06eac4a9eda 100644 --- a/netwerk/base/public/nsReadLine.h +++ b/netwerk/base/public/nsReadLine.h @@ -22,6 +22,7 @@ * * Contributor(s): * Christian Biesinger + * Mats Palmgren * * Alternatively, the contents of this file may be used under the terms of * either the GNU General Public License Version 2 or later (the "GPL"), or @@ -60,21 +61,23 @@ * Buffer size. This many bytes will be buffered. If a line is longer than this, * the partial line will be appended to the out parameter of NS_ReadLine and the * buffer will be emptied. + * Note: if you change this constant, please update the regression test in + * netwerk/test/unit/test_readline.js accordingly (bug 397850). */ #define kLineBufferSize 4096 /** * @internal * Line buffer structure, buffers data from an input stream. + * The buffer is empty when |start| == |end|. + * Invariant: |start| <= |end| */ template class nsLineBuffer { public: CharT buf[kLineBufferSize+1]; CharT* start; - CharT* current; CharT* end; - PRBool empty; }; /** @@ -105,8 +108,7 @@ NS_InitLineBuffer (nsLineBuffer ** aBufferPtr) { if (!(*aBufferPtr)) return NS_ERROR_OUT_OF_MEMORY; - (*aBufferPtr)->start = (*aBufferPtr)->current = (*aBufferPtr)->end = (*aBufferPtr)->buf; - (*aBufferPtr)->empty = PR_TRUE; + (*aBufferPtr)->start = (*aBufferPtr)->end = (*aBufferPtr)->buf; return NS_OK; } @@ -136,76 +138,62 @@ NS_InitLineBuffer (nsLineBuffer ** aBufferPtr) { template nsresult NS_ReadLine (StreamType* aStream, nsLineBuffer * aBuffer, - StringType & aLine, PRBool *more) { - nsresult rv = NS_OK; - PRUint32 bytesRead; - *more = PR_TRUE; - PRBool eolStarted = PR_FALSE; - CharT eolchar = '\0'; + StringType & aLine, PRBool *more) +{ + CharT eolchar = 0; // the first eol char or 1 after \r\n or \n\r is found + aLine.Truncate(); + while (1) { // will be returning out of this loop on eol or eof - if (aBuffer->empty) { // buffer is empty. Read into it. - rv = aStream->Read(aBuffer->buf, kLineBufferSize, &bytesRead); - if (NS_FAILED(rv)) // read failed - return rv; - if (bytesRead == 0) { // end of file + if (aBuffer->start == aBuffer->end) { // buffer is empty. Read into it. + PRUint32 bytesRead; + nsresult rv = aStream->Read(aBuffer->buf, kLineBufferSize, &bytesRead); + if (NS_FAILED(rv) || NS_UNLIKELY(bytesRead == 0)) { *more = PR_FALSE; - return NS_OK; + return rv; } + aBuffer->start = aBuffer->buf; aBuffer->end = aBuffer->buf + bytesRead; - aBuffer->empty = PR_FALSE; - *(aBuffer->end) = '\0'; // null-terminate this thing + *(aBuffer->end) = '\0'; } - // walk the buffer looking for an end-of-line - while (aBuffer->current < aBuffer->end) { - if (eolStarted) { - if ((eolchar == '\n' && *(aBuffer->current) == '\r') || - (eolchar == '\r' && *(aBuffer->current) == '\n')) { // line end - (aBuffer->current)++; - aBuffer->start = aBuffer->current; - } - eolStarted = PR_FALSE; - return NS_OK; - } else if (*(aBuffer->current) == '\n' || - *(aBuffer->current) == '\r') { // line end - eolStarted = PR_TRUE; - eolchar = *(aBuffer->current); - *(aBuffer->current) = '\0'; - aLine.Append(aBuffer->start); - (aBuffer->current)++; - aBuffer->start = aBuffer->current; - } else { - eolStarted = PR_FALSE; - (aBuffer->current)++; + + /* + * Walk the buffer looking for an end-of-line. + * There are 3 cases to consider: + * 1. the eol char is the last char in the buffer + * 2. the eol char + one more char at the end of the buffer + * 3. the eol char + two or more chars at the end of the buffer + * we need at least one char after the first eol char to determine if + * it's a \r\n or \n\r sequence (and skip over it), and we need one + * more char after the end-of-line to set |more| correctly. + */ + CharT* current = aBuffer->start; + if (NS_LIKELY(eolchar == 0)) { + for ( ; current < aBuffer->end; ++current) { + if (*current == '\n' || *current == '\r') { + eolchar = *current; + *current++ = '\0'; + aLine.Append(aBuffer->start); + break; + } + } + } + if (NS_LIKELY(eolchar != 0)) { + for ( ; current < aBuffer->end; ++current) { + if ((eolchar == '\r' && *current == '\n') || + (eolchar == '\n' && *current == '\r')) { + eolchar = 1; + continue; + } + aBuffer->start = current; + *more = PR_TRUE; + return NS_OK; } } - // append whatever we currently have to the string - aLine.Append(aBuffer->start); - - // we've run out of buffer. Begin anew - aBuffer->current = aBuffer->start = aBuffer->buf; - aBuffer->empty = PR_TRUE; - - if (eolStarted) { // have to read another char and possibly skip over it - rv = aStream->Read(aBuffer->buf, 1, &bytesRead); - if (NS_FAILED(rv)) // read failed - return rv; - if (bytesRead == 0) { // end of file - *more = PR_FALSE; - return NS_OK; - } - if ((eolchar == '\n' && *(aBuffer->buf) == '\r') || - (eolchar == '\r' && *(aBuffer->buf) == '\n')) { - // Just return and all is good -- we've skipped the extra newline char - return NS_OK; - } else { - // we have a byte that we should look at later - aBuffer->empty = PR_FALSE; - aBuffer->end = aBuffer->buf + 1; - *(aBuffer->end) = '\0'; - } - } + if (eolchar == 0) + aLine.Append(aBuffer->start); + aBuffer->start = aBuffer->end; // mark the buffer empty } }