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Bug 1741219 - Remove Expat usage from nsHtml5StreamParser. r=smaug 

To be overwritten by the patch for https://bugzilla.mozilla.org/show_bug.cgi?id=1701828 .

Differential Revision: https://phabricator.services.mozilla.com/D131215
This commit is contained in:
Henri Sivonen 2021-11-16 16:02:04 +00:00
Родитель 3cf56f8e1f
Коммит e266e0f13a
2 изменённых файлов: 30 добавлений и 131 удалений
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152
parser/html/nsHtml5StreamParser.cpp
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@ -79,11 +79,6 @@
#include "nsThreadUtils.h"
#include "nsXULAppAPI.h"
// Include expat after the other, since it defines XML_NS, which conflicts with
// our symbol names.
#include "expat_config.h"
#include "expat.h"
extern "C" {
// Defined in intl/encoding_glue/src/lib.rs
const mozilla::Encoding* xmldecl_parse(const uint8_t* buf, size_t buf_len);
@ -503,71 +498,6 @@ void nsHtml5StreamParser::SetupDecodingFromUtf16BogoXml(
mLastBuffer->AdvanceEnd(3);
}
void nsHtml5StreamParser::SetEncodingFromExpat(const char16_t* aEncoding) {
if (aEncoding) {
nsDependentString utf16(aEncoding);
nsAutoCString utf8;
CopyUTF16toUTF8(utf16, utf8);
auto encoding = PreferredForInternalEncodingDecl(utf8);
if (encoding) {
mEncoding = WrapNotNull(encoding);
mCharsetSource = kCharsetFromMetaTag; // closest for XML
mTreeBuilder->SetDocumentCharset(mEncoding, mCharsetSource);
return;
}
// else the page declared an encoding Gecko doesn't support and we'd
// end up defaulting to UTF-8 anyway. Might as well fall through here
// right away and let the encoding be set to UTF-8 which we'd default to
// anyway.
}
mEncoding = UTF_8_ENCODING; // XML defaults to UTF-8 without a BOM
mCharsetSource = kCharsetFromMetaTag; // means confident
mTreeBuilder->SetDocumentCharset(mEncoding, mCharsetSource);
}
// A separate user data struct is used instead of passing the
// nsHtml5StreamParser instance as user data in order to avoid including
// expat.h in nsHtml5StreamParser.h. Doing that would cause naming conflicts.
// Using a separate user data struct also avoids bloating nsHtml5StreamParser
// by one pointer.
struct UserData {
XML_Parser mExpat;
nsHtml5StreamParser* mStreamParser;
};
// Using no-namespace handler callbacks to avoid including expat.h in
// nsHtml5StreamParser.h, since doing so would cause naming conclicts.
static void HandleXMLDeclaration(void* aUserData, const XML_Char* aVersion,
const XML_Char* aEncoding, int aStandalone) {
UserData* ud = static_cast<UserData*>(aUserData);
ud->mStreamParser->SetEncodingFromExpat(
reinterpret_cast<const char16_t*>(aEncoding));
XML_StopParser(ud->mExpat, false);
}
static void HandleStartElement(void* aUserData, const XML_Char* aName,
const XML_Char** aAtts) {
UserData* ud = static_cast<UserData*>(aUserData);
XML_StopParser(ud->mExpat, false);
}
static void HandleEndElement(void* aUserData, const XML_Char* aName) {
UserData* ud = static_cast<UserData*>(aUserData);
XML_StopParser(ud->mExpat, false);
}
static void HandleComment(void* aUserData, const XML_Char* aName) {
UserData* ud = static_cast<UserData*>(aUserData);
XML_StopParser(ud->mExpat, false);
}
static void HandleProcessingInstruction(void* aUserData,
const XML_Char* aTarget,
const XML_Char* aData) {
UserData* ud = static_cast<UserData*>(aUserData);
XML_StopParser(ud->mExpat, false);
}
void nsHtml5StreamParser::FinalizeSniffingWithDetector(
Span<const uint8_t> aFromSegment, uint32_t aCountToSniffingLimit,
bool aEof) {
@ -602,63 +532,39 @@ nsresult nsHtml5StreamParser::FinalizeSniffing(Span<const uint8_t> aFromSegment,
MOZ_ASSERT(mCharsetSource < kCharsetFromXmlDeclarationUtf16,
"Should not finalize sniffing with strong decision already made.");
if (mMode == VIEW_SOURCE_XML) {
static const XML_Memory_Handling_Suite memsuite = {
(void* (*)(size_t))moz_xmalloc, (void* (*)(void*, size_t))moz_xrealloc,
free};
static const char16_t kExpatSeparator[] = {0xFFFF, '\0'};
static const char16_t kISO88591[] = {'I', 'S', 'O', '-', '8', '8',
'5', '9', '-', '1', '\0'};
UserData ud;
ud.mStreamParser = this;
// If we got this far, the stream didn't have a BOM. UTF-16-encoded XML
// documents MUST begin with a BOM. We don't support EBCDIC and such.
// Thus, at this point, what we have is garbage or something encoded using
// a rough ASCII superset. ISO-8859-1 allows us to decode ASCII bytes
// without throwing errors when bytes have the most significant bit set
// and without triggering expat's unknown encoding code paths. This is
// enough to be able to use expat to parse the XML declaration in order
// to extract the encoding name from it.
ud.mExpat = XML_ParserCreate_MM(kISO88591, &memsuite, kExpatSeparator);
XML_SetXmlDeclHandler(ud.mExpat, HandleXMLDeclaration);
XML_SetElementHandler(ud.mExpat, HandleStartElement, HandleEndElement);
XML_SetCommentHandler(ud.mExpat, HandleComment);
XML_SetProcessingInstructionHandler(ud.mExpat, HandleProcessingInstruction);
XML_SetUserData(ud.mExpat, static_cast<void*>(&ud));
XML_Status status = XML_STATUS_OK;
// aFromSegment points to the data obtained from the current network
// event. mSniffingBuffer (if it exists) contains the data obtained before
// the current event. Thus, mSniffingLenth bytes of mSniffingBuffer
// followed by aCountToSniffingLimit bytes from aFromSegment are the
// first 1024 bytes of the file (or the file as a whole if the file is
// 1024 bytes long or shorter). Thus, we parse both buffers, but if the
// first call succeeds already, we skip parsing the second buffer.
if (mSniffingBuffer) {
status = XML_Parse(ud.mExpat,
reinterpret_cast<const char*>(mSniffingBuffer.get()),
mSniffingLength, false);
// Copypaste from the next non-XML block below.
// Not bothering to refactor these nicely, since this will get overwritten
// by the patch for https://bugzilla.mozilla.org/show_bug.cgi?id=1701828
// soon enough.
MOZ_ASSERT(mCharsetSource < kCharsetFromMetaTag);
const uint8_t* buf;
size_t bufLen;
MOZ_ASSERT(aFromSegment.Length() >= aCountToSniffingLimit);
if (mSniffingLength) {
// Copy data to a contiguous buffer if we already have something buffered
// up.
MOZ_ASSERT(mSniffingLength + aCountToSniffingLimit <=
SNIFFING_BUFFER_SIZE);
memcpy(mSniffingBuffer.get() + mSniffingLength, aFromSegment.Elements(),
aCountToSniffingLimit);
mSniffingLength += aCountToSniffingLimit;
aFromSegment = aFromSegment.From(aCountToSniffingLimit);
buf = mSniffingBuffer.get();
bufLen = mSniffingLength;
} else {
buf = aFromSegment.Elements();
bufLen = aCountToSniffingLimit;
}
if (status == XML_STATUS_OK && mCharsetSource < kCharsetFromMetaTag) {
mozilla::Unused << XML_Parse(
ud.mExpat, reinterpret_cast<const char*>(aFromSegment.Elements()),
aCountToSniffingLimit, false);
}
XML_ParserFree(ud.mExpat);
if (mCharsetSource < kCharsetFromMetaTag) {
// Failed to get an encoding from the XML declaration. XML defaults
// confidently to UTF-8 in this case.
// It is also possible that the document has an XML declaration that is
// longer than 1024 bytes, but that case is not worth worrying about.
const Encoding* encoding = xmldecl_parse(buf, bufLen);
if (encoding) {
mEncoding = WrapNotNull(encoding);
} else {
// XML defaults to UTF-8.
mEncoding = UTF_8_ENCODING;
}
mCharsetSource = kCharsetFromMetaTag; // means confident
mTreeBuilder->SetDocumentCharset(mEncoding, mCharsetSource);
}
return SetupDecodingAndWriteSniffingBufferAndCurrentSegment(aFromSegment);
}

7
parser/html/nsHtml5StreamParser.h
Просмотреть файл

@ -263,13 +263,6 @@ class nsHtml5StreamParser final : public nsISupports {
void DropTimer();
/**
* Sets mEncoding and mCharsetSource appropriately for the XML View Source
* case if aEncoding names a supported rough ASCII superset and sets
* the mEncoding and mCharsetSource to the UTF-8 default otherwise.
*/
void SetEncodingFromExpat(const char16_t* aEncoding);
/**
* Sets the URL for View Source title in case this parser ends up being
* used for View Source. If aURL is a view-source: URL, takes the inner