gecko-dev/parser/htmlparser/nsScanner.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 sw=2 et tw=78: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//#define __INCREMENTAL 1
#include "nsScanner.h"
#include "mozilla/Attributes.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Encoding.h"
#include "nsDebug.h"
#include "nsReadableUtils.h"
#include "nsUTF8Utils.h" // for LossyConvertEncoding
#include "nsCRT.h"
#include "nsParser.h"
#include "nsCharsetSource.h"
nsReadEndCondition::nsReadEndCondition(const char16_t* aTerminateChars)
: mChars(aTerminateChars),
mFilter(char16_t(~0)) // All bits set
{
// Build filter that will be used to filter out characters with
// bits that none of the terminal chars have. This works very well
// because terminal chars often have only the last 4-6 bits set and
// normal ascii letters have bit 7 set. Other letters have even higher
// bits set.
// Calculate filter
const char16_t* current = aTerminateChars;
char16_t terminalChar = *current;
while (terminalChar) {
mFilter &= ~terminalChar;
++current;
terminalChar = *current;
}
}
/**
* Use this constructor if you want i/o to be based on
* a single string you hand in during construction.
* This short cut was added for Javascript.
*
* @update gess 5/12/98
* @param aMode represents the parser mode (nav, other)
* @return
*/
nsScanner::nsScanner(const nsAString& anHTMLString) {
MOZ_COUNT_CTOR(nsScanner);
mSlidingBuffer = nullptr;
if (AppendToBuffer(anHTMLString)) {
mSlidingBuffer->BeginReading(mCurrentPosition);
} else {
/* XXX see hack below, re: bug 182067 */
memset(&mCurrentPosition, 0, sizeof(mCurrentPosition));
mEndPosition = mCurrentPosition;
}
mMarkPosition = mCurrentPosition;
mIncremental = false;
mUnicodeDecoder = nullptr;
mCharsetSource = kCharsetUninitialized;
}
/**
* Use this constructor if you want i/o to be based on strings
* the scanner receives. If you pass a null filename, you
* can still provide data to the scanner via append.
*/
nsScanner::nsScanner(nsString& aFilename, bool aCreateStream)
: mFilename(aFilename) {
MOZ_COUNT_CTOR(nsScanner);
NS_ASSERTION(!aCreateStream, "This is always true.");
mSlidingBuffer = nullptr;
// XXX This is a big hack. We need to initialize the iterators to something.
// What matters is that mCurrentPosition == mEndPosition, so that our methods
// believe that we are at EOF (see bug 182067). We null out mCurrentPosition
// so that we have some hope of catching null pointer dereferences associated
// with this hack. --darin
memset(&mCurrentPosition, 0, sizeof(mCurrentPosition));
mMarkPosition = mCurrentPosition;
mEndPosition = mCurrentPosition;
mIncremental = true;
mUnicodeDecoder = nullptr;
mCharsetSource = kCharsetUninitialized;
// XML defaults to UTF-8 and about:blank is UTF-8, too.
SetDocumentCharset(UTF_8_ENCODING, kCharsetFromDocTypeDefault);
}
nsresult nsScanner::SetDocumentCharset(NotNull<const Encoding*> aEncoding,
int32_t aSource) {
if (aSource < mCharsetSource) // priority is lower than the current one
return NS_OK;
mCharsetSource = aSource;
nsCString charsetName;
aEncoding->Name(charsetName);
if (!mCharset.IsEmpty() && charsetName.Equals(mCharset)) {
return NS_OK; // no difference, don't change it
}
// different, need to change it
mCharset.Assign(charsetName);
mUnicodeDecoder = aEncoding->NewDecoderWithBOMRemoval();
return NS_OK;
}
/**
* default destructor
*
* @update gess 3/25/98
* @param
* @return
*/
nsScanner::~nsScanner() {
delete mSlidingBuffer;
MOZ_COUNT_DTOR(nsScanner);
}
/**
* Resets current offset position of input stream to marked position.
* This allows us to back up to this point if the need should arise,
* such as when tokenization gets interrupted.
* NOTE: IT IS REALLY BAD FORM TO CALL RELEASE WITHOUT CALLING MARK FIRST!
*
* @update gess 5/12/98
* @param
* @return
*/
void nsScanner::RewindToMark(void) {
if (mSlidingBuffer) {
mCurrentPosition = mMarkPosition;
}
}
/**
* Records current offset position in input stream. This allows us
* to back up to this point if the need should arise, such as when
* tokenization gets interrupted.
*
* @update gess 7/29/98
* @param
* @return
*/
int32_t nsScanner::Mark() {
int32_t distance = 0;
if (mSlidingBuffer) {
nsScannerIterator oldStart;
mSlidingBuffer->BeginReading(oldStart);
distance = Distance(oldStart, mCurrentPosition);
mSlidingBuffer->DiscardPrefix(mCurrentPosition);
mSlidingBuffer->BeginReading(mCurrentPosition);
mMarkPosition = mCurrentPosition;
}
return distance;
}
/**
* Insert data to our underlying input buffer as
* if it were read from an input stream.
*
* @update harishd 01/12/99
* @return error code
*/
bool nsScanner::UngetReadable(const nsAString& aBuffer) {
if (!mSlidingBuffer) {
return false;
}
mSlidingBuffer->UngetReadable(aBuffer, mCurrentPosition);
mSlidingBuffer->BeginReading(
mCurrentPosition); // Insertion invalidated our iterators
mSlidingBuffer->EndReading(mEndPosition);
return true;
}
/**
* Append data to our underlying input buffer as
* if it were read from an input stream.
*
* @update gess4/3/98
* @return error code
*/
nsresult nsScanner::Append(const nsAString& aBuffer) {
if (!AppendToBuffer(aBuffer)) return NS_ERROR_OUT_OF_MEMORY;
return NS_OK;
}
/**
*
*
* @update gess 5/21/98
* @param
* @return
*/
nsresult nsScanner::Append(const char* aBuffer, uint32_t aLen) {
nsresult res = NS_OK;
if (mUnicodeDecoder) {
CheckedInt<size_t> needed = mUnicodeDecoder->MaxUTF16BufferLength(aLen);
if (!needed.isValid()) {
return NS_ERROR_OUT_OF_MEMORY;
}
CheckedInt<uint32_t> allocLen(1); // null terminator due to legacy sadness
allocLen += needed.value();
if (!allocLen.isValid()) {
return NS_ERROR_OUT_OF_MEMORY;
}
nsScannerString::Buffer* buffer =
nsScannerString::AllocBuffer(allocLen.value());
NS_ENSURE_TRUE(buffer, NS_ERROR_OUT_OF_MEMORY);
char16_t* unichars = buffer->DataStart();
uint32_t result;
size_t read;
size_t written;
Tie(result, read, written) =
mUnicodeDecoder->DecodeToUTF16WithoutReplacement(
AsBytes(Span(aBuffer, aLen)), Span(unichars, needed.value()),
false); // Retain bug about failure to handle EOF
MOZ_ASSERT(result != kOutputFull);
MOZ_ASSERT(read <= aLen);
MOZ_ASSERT(written <= needed.value());
if (result != kInputEmpty) {
// Since about:blank is empty, this line runs only for XML. Use a
// character that's illegal in XML instead of U+FFFD in order to make
// expat flag the error. There is no need to loop and convert more, since
// expat will stop here anyway.
unichars[written++] = 0xFFFF;
}
buffer->SetDataLength(written);
// Don't propagate return code of unicode decoder
// since it doesn't reflect on our success or failure
// - Ref. bug 87110
res = NS_OK;
if (!AppendToBuffer(buffer)) res = NS_ERROR_OUT_OF_MEMORY;
} else {
NS_WARNING("No decoder found.");
res = NS_ERROR_FAILURE;
}
return res;
}
/**
* retrieve next char from scanners internal input stream
*
* @update gess 3/25/98
* @param
* @return error code reflecting read status
*/
nsresult nsScanner::GetChar(char16_t& aChar) {
if (!mSlidingBuffer || mCurrentPosition == mEndPosition) {
aChar = 0;
return NS_ERROR_HTMLPARSER_EOF;
}
aChar = *mCurrentPosition++;
return NS_OK;
}
void nsScanner::BindSubstring(nsScannerSubstring& aSubstring,
const nsScannerIterator& aStart,
const nsScannerIterator& aEnd) {
aSubstring.Rebind(*mSlidingBuffer, aStart, aEnd);
}
void nsScanner::CurrentPosition(nsScannerIterator& aPosition) {
aPosition = mCurrentPosition;
}
void nsScanner::EndReading(nsScannerIterator& aPosition) {
aPosition = mEndPosition;
}
void nsScanner::SetPosition(nsScannerIterator& aPosition, bool aTerminate) {
if (mSlidingBuffer) {
mCurrentPosition = aPosition;
if (aTerminate && (mCurrentPosition == mEndPosition)) {
mMarkPosition = mCurrentPosition;
mSlidingBuffer->DiscardPrefix(mCurrentPosition);
}
}
}
bool nsScanner::AppendToBuffer(nsScannerString::Buffer* aBuf) {
if (!mSlidingBuffer) {
mSlidingBuffer = new nsScannerString(aBuf);
if (!mSlidingBuffer) return false;
mSlidingBuffer->BeginReading(mCurrentPosition);
mMarkPosition = mCurrentPosition;
mSlidingBuffer->EndReading(mEndPosition);
} else {
mSlidingBuffer->AppendBuffer(aBuf);
if (mCurrentPosition == mEndPosition) {
mSlidingBuffer->BeginReading(mCurrentPosition);
}
mSlidingBuffer->EndReading(mEndPosition);
}
return true;
}
/**
* call this to copy bytes out of the scanner that have not yet been consumed
* by the tokenization process.
*
* @update gess 5/12/98
* @param aCopyBuffer is where the scanner buffer will be copied to
* @return true if OK or false on OOM
*/
bool nsScanner::CopyUnusedData(nsString& aCopyBuffer) {
if (!mSlidingBuffer) {
aCopyBuffer.Truncate();
return true;
}
nsScannerIterator start, end;
start = mCurrentPosition;
end = mEndPosition;
return CopyUnicodeTo(start, end, aCopyBuffer);
}
/**
* Retrieve the name of the file that the scanner is reading from.
* In some cases, it's just a given name, because the scanner isn't
* really reading from a file.
*
* @update gess 5/12/98
* @return
*/
nsString& nsScanner::GetFilename(void) { return mFilename; }
/**
* Conduct self test. Actually, selftesting for this class
* occurs in the parser selftest.
*
* @update gess 3/25/98
* @param
* @return
*/
void nsScanner::SelfTest(void) {
#ifdef _DEBUG
#endif
}