mirror of
https://github.com/classilla/tenfourfox.git
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153 lines
5.1 KiB
C++
153 lines
5.1 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsNCRFallbackEncoderWrapper.h"
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#include "mozilla/dom/EncodingUtils.h"
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nsNCRFallbackEncoderWrapper::nsNCRFallbackEncoderWrapper(const nsACString& aEncoding)
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: mEncoder(mozilla::dom::EncodingUtils::EncoderForEncoding(aEncoding))
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{
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}
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nsNCRFallbackEncoderWrapper::~nsNCRFallbackEncoderWrapper()
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{
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}
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bool
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nsNCRFallbackEncoderWrapper::WriteNCR(nsACString& aBytes,
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uint32_t& aDstWritten,
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int32_t aUnmappable)
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{
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// To avoid potentially shrinking aBytes and then growing it back, use
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// another string for number formatting.
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nsAutoCString ncr("&#");
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ncr.AppendInt(aUnmappable);
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ncr.Append(';');
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uint32_t ncrLen = ncr.Length();
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uint32_t needed = aDstWritten + ncrLen;
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if (needed > INT32_MAX) {
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return false;
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}
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if (needed > aBytes.Length() && !aBytes.SetLength(needed,
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mozilla::fallible_t())) {
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return false;
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}
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memcpy(aBytes.BeginWriting() + aDstWritten,
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ncr.BeginReading(),
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ncrLen);
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aDstWritten += ncrLen;
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return true;
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}
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bool
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nsNCRFallbackEncoderWrapper::Encode(const nsAString& aUtf16,
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nsACString& aBytes)
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{
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// nsIUnicodeEncoder uses int32_t for sizes :-(
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if (aUtf16.Length() > INT32_MAX) {
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return false;
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}
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const char16_t* src = aUtf16.BeginReading();
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const char16_t* srcEnd = aUtf16.EndReading();
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uint32_t dstWritten = 0;
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for (;;) {
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int32_t srcLen = srcEnd - src;
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int32_t dstLen = 0;
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nsresult rv = mEncoder->GetMaxLength(src, srcLen, &dstLen);
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if (NS_FAILED(rv)) {
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return false;
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}
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uint32_t needed = dstWritten + dstLen;
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if (needed > INT32_MAX) {
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return false;
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}
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// Behind the scenes SetLength() makes the underlying allocation not have
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// slop, so we don't need to round up here.
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if (needed > aBytes.Length() && !aBytes.SetLength(needed,
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mozilla::fallible_t())) {
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return false;
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}
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// We need to re-obtain the destination pointer on every iteration, because
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// SetLength() invalidates it.
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char* dst = aBytes.BeginWriting() + dstWritten;
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dstLen = aBytes.Length() - dstWritten;
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mEncoder->Reset();
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rv = mEncoder->Convert(src, &srcLen, dst, &dstLen);
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// Update state tracking
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src += srcLen;
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dstWritten += dstLen;
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if (rv == NS_OK_UENC_MOREOUTPUT) {
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MOZ_ASSERT_UNREACHABLE("GetMaxLength must have returned a bogus length.");
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return false;
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}
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if (rv == NS_ERROR_UENC_NOMAPPING) {
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int32_t unmappable;
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// The unmappable code unit or the first half of an unmappable surrogate
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// pair is consumed by the encoder.
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MOZ_ASSERT(srcLen > 0, "Encoder should have consumed some input.");
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char16_t codeUnit = src[-1];
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// Let's see if it is a surrogate
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size_t highBits = (codeUnit & 0xFC00);
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if (highBits == 0xD800) {
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// high surrogate
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// Let's see if we actually have a surrogate pair.
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char16_t next;
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if (src < srcEnd && NS_IS_LOW_SURROGATE((next = *src))) {
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src++; // consume the low surrogate
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unmappable = SURROGATE_TO_UCS4(codeUnit, next);
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} else {
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// unpaired surrogate.
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unmappable = 0xFFFD;
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}
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} else if (highBits == 0xDC00) {
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// low surrogate
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// This must be an unpaired surrogate.
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unmappable = 0xFFFD;
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} else {
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// not a surrogate
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unmappable = codeUnit;
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}
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// If we are encoding to ISO-2022-JP, we need to let the encoder to
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// generate a transition to the ASCII state if not already there.
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dst = aBytes.BeginWriting() + dstWritten;
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dstLen = aBytes.Length() - dstWritten;
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rv = mEncoder->Finish(dst, &dstLen);
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dstWritten += dstLen;
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if (rv != NS_OK) {
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// Failures should be impossible if GetMaxLength works. Big5 is the
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// only case where Finish() may return NS_ERROR_UENC_NOMAPPING but
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// that should never happen right after Convert() has returned it.
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MOZ_ASSERT_UNREACHABLE("Broken encoder.");
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return false;
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}
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if (!WriteNCR(aBytes, dstWritten, unmappable)) {
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return false;
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}
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continue;
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}
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if (!(rv == NS_OK || rv == NS_OK_UENC_MOREINPUT)) {
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return false;
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}
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MOZ_ASSERT(src == srcEnd, "Converter did not consume all input.");
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dst = aBytes.BeginWriting() + dstWritten;
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dstLen = aBytes.Length() - dstWritten;
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rv = mEncoder->Finish(dst, &dstLen);
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dstWritten += dstLen;
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if (rv == NS_OK_UENC_MOREOUTPUT) {
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MOZ_ASSERT_UNREACHABLE("GetMaxLength must have returned a bogus length.");
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return false;
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}
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if (rv == NS_ERROR_UENC_NOMAPPING) {
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// Big5
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if (!WriteNCR(aBytes, dstWritten, 0xFFFD)) {
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return false;
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}
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}
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return aBytes.SetLength(dstWritten, mozilla::fallible_t());
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}
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}
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