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gecko-dev/layout/style/nsCSSScanner.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
/* tokenization of CSS style sheets */
#include "nsCSSScanner.h"
#include "nsStyleUtil.h"
#include "nsISupportsImpl.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/css/ErrorReporter.h"
#include "mozilla/Likely.h"
#include <algorithm>
/* Character class tables and related helper functions. */
static const uint8_t IS_HEX_DIGIT = 0x01;
static const uint8_t IS_IDSTART = 0x02;
static const uint8_t IS_IDCHAR = 0x04;
static const uint8_t IS_URL_CHAR = 0x08;
static const uint8_t IS_HSPACE = 0x10;
static const uint8_t IS_VSPACE = 0x20;
static const uint8_t IS_SPACE = IS_HSPACE|IS_VSPACE;
static const uint8_t IS_STRING = 0x40;
#define H IS_HSPACE
#define V IS_VSPACE
#define I IS_IDCHAR
#define J IS_IDSTART
#define U IS_URL_CHAR
#define S IS_STRING
#define X IS_HEX_DIGIT
#define SH S|H
#define SU S|U
#define SUI S|U|I
#define SUIJ S|U|I|J
#define SUIX S|U|I|X
#define SUIJX S|U|I|J|X
static const uint8_t gLexTable[] = {
// 00 01 02 03 04 05 06 07
0, S, S, S, S, S, S, S,
// 08 TAB LF 0B FF CR 0E 0F
S, SH, V, S, V, V, S, S,
// 10 11 12 13 14 15 16 17
S, S, S, S, S, S, S, S,
// 18 19 1A 1B 1C 1D 1E 1F
S, S, S, S, S, S, S, S,
//SPC ! " # $ % & '
SH, SU, 0, SU, SU, SU, SU, 0,
// ( ) * + , - . /
S, S, SU, SU, SU, SUI, SU, SU,
// 0 1 2 3 4 5 6 7
SUIX, SUIX, SUIX, SUIX, SUIX, SUIX, SUIX, SUIX,
// 8 9 : ; < = > ?
SUIX, SUIX, SU, SU, SU, SU, SU, SU,
// @ A B C D E F G
SU,SUIJX,SUIJX,SUIJX,SUIJX,SUIJX,SUIJX, SUIJ,
// H I J K L M N O
SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ,
// P Q R S T U V W
SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ,
// X Y Z [ \ ] ^ _
SUIJ, SUIJ, SUIJ, SU, J, SU, SU, SUIJ,
// ` a b c d e f g
SU,SUIJX,SUIJX,SUIJX,SUIJX,SUIJX,SUIJX, SUIJ,
// h i j k l m n o
SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ,
// p q r s t u v w
SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ, SUIJ,
// x y z { | } ~ 7F
SUIJ, SUIJ, SUIJ, SU, SU, SU, SU, S,
};
static_assert(MOZ_ARRAY_LENGTH(gLexTable) == 128,
"gLexTable expected to cover all 128 ASCII characters");
#undef I
#undef J
#undef U
#undef S
#undef X
#undef SH
#undef SU
#undef SUI
#undef SUIJ
#undef SUIX
#undef SUIJX
/**
* True if 'ch' is in character class 'cls', which should be one of
* the constants above or some combination of them. All characters
* above U+007F are considered to be in 'cls'. EOF is never in 'cls'.
*/
static inline bool
IsOpenCharClass(int32_t ch, uint8_t cls) {
return ch >= 0 && (ch >= 128 || (gLexTable[ch] & cls) != 0);
}
/**
* True if 'ch' is in character class 'cls', which should be one of
* the constants above or some combination of them. No characters
* above U+007F are considered to be in 'cls'. EOF is never in 'cls'.
*/
static inline bool
IsClosedCharClass(int32_t ch, uint8_t cls) {
return uint32_t(ch) < 128 && (gLexTable[ch] & cls) != 0;
}
/**
* True if 'ch' is CSS whitespace, i.e. any of the ASCII characters
* TAB, LF, FF, CR, or SPC.
*/
static inline bool
IsWhitespace(int32_t ch) {
return IsClosedCharClass(ch, IS_SPACE);
}
/**
* True if 'ch' is horizontal whitespace, i.e. TAB or SPC.
*/
static inline bool
IsHorzSpace(int32_t ch) {
return IsClosedCharClass(ch, IS_HSPACE);
}
/**
* True if 'ch' is vertical whitespace, i.e. LF, FF, or CR. Vertical
* whitespace requires special handling when consumed, see AdvanceLine.
*/
static inline bool
IsVertSpace(int32_t ch) {
return IsClosedCharClass(ch, IS_VSPACE);
}
/**
* True if 'ch' is a character that can appear in the middle of an identifier.
* This includes U+0000 since it is handled as U+FFFD, but for purposes of
* GatherText it should not be included in IsOpenCharClass.
*/
static inline bool
IsIdentChar(int32_t ch) {
return IsOpenCharClass(ch, IS_IDCHAR) || ch == 0;
}
/**
* True if 'ch' is a character that by itself begins an identifier.
* This includes U+0000 since it is handled as U+FFFD, but for purposes of
* GatherText it should not be included in IsOpenCharClass.
* (This is a subset of IsIdentChar.)
*/
static inline bool
IsIdentStart(int32_t ch) {
return IsOpenCharClass(ch, IS_IDSTART) || ch == 0;
}
/**
* True if the two-character sequence aFirstChar+aSecondChar begins an
* identifier.
*/
static inline bool
StartsIdent(int32_t aFirstChar, int32_t aSecondChar)
{
return IsIdentStart(aFirstChar) ||
(aFirstChar == '-' && (aSecondChar == '-' || IsIdentStart(aSecondChar)));
}
/**
* True if 'ch' is a decimal digit.
*/
static inline bool
IsDigit(int32_t ch) {
return (ch >= '0') && (ch <= '9');
}
/**
* True if 'ch' is a hexadecimal digit.
*/
static inline bool
IsHexDigit(int32_t ch) {
return IsClosedCharClass(ch, IS_HEX_DIGIT);
}
/**
* Assuming that 'ch' is a decimal digit, return its numeric value.
*/
static inline uint32_t
DecimalDigitValue(int32_t ch)
{
return ch - '0';
}
/**
* Assuming that 'ch' is a hexadecimal digit, return its numeric value.
*/
static inline uint32_t
HexDigitValue(int32_t ch)
{
if (IsDigit(ch)) {
return DecimalDigitValue(ch);
} else {
// Note: c&7 just keeps the low three bits which causes
// upper and lower case alphabetics to both yield their
// "relative to 10" value for computing the hex value.
return (ch & 0x7) + 9;
}
}
/**
* If 'ch' can be the first character of a two-character match operator
* token, return the token type code for that token, otherwise return
* eCSSToken_Symbol to indicate that it can't.
*/
static inline nsCSSTokenType
MatchOperatorType(int32_t ch)
{
switch (ch) {
case '~': return eCSSToken_Includes;
case '|': return eCSSToken_Dashmatch;
case '^': return eCSSToken_Beginsmatch;
case '$': return eCSSToken_Endsmatch;
case '*': return eCSSToken_Containsmatch;
default: return eCSSToken_Symbol;
}
}
/* Out-of-line nsCSSToken methods. */
/**
* Append the textual representation of |this| to |aBuffer|.
*/
void
nsCSSToken::AppendToString(nsString& aBuffer) const
{
switch (mType) {
case eCSSToken_Ident:
nsStyleUtil::AppendEscapedCSSIdent(mIdent, aBuffer);
break;
case eCSSToken_AtKeyword:
aBuffer.Append('@');
nsStyleUtil::AppendEscapedCSSIdent(mIdent, aBuffer);
break;
case eCSSToken_ID:
case eCSSToken_Hash:
aBuffer.Append('#');
nsStyleUtil::AppendEscapedCSSIdent(mIdent, aBuffer);
break;
case eCSSToken_Function:
nsStyleUtil::AppendEscapedCSSIdent(mIdent, aBuffer);
aBuffer.Append('(');
break;
case eCSSToken_URL:
case eCSSToken_Bad_URL:
aBuffer.AppendLiteral("url(");
if (mSymbol != char16_t(0)) {
nsStyleUtil::AppendEscapedCSSString(mIdent, aBuffer, mSymbol);
} else {
aBuffer.Append(mIdent);
}
if (mType == eCSSToken_URL) {
aBuffer.Append(char16_t(')'));
}
break;
case eCSSToken_Number:
if (mIntegerValid) {
aBuffer.AppendInt(mInteger, 10);
} else {
aBuffer.AppendFloat(mNumber);
}
break;
case eCSSToken_Percentage:
aBuffer.AppendFloat(mNumber * 100.0f);
aBuffer.Append(char16_t('%'));
break;
case eCSSToken_Dimension:
if (mIntegerValid) {
aBuffer.AppendInt(mInteger, 10);
} else {
aBuffer.AppendFloat(mNumber);
}
nsStyleUtil::AppendEscapedCSSIdent(mIdent, aBuffer);
break;
case eCSSToken_Bad_String:
nsStyleUtil::AppendEscapedCSSString(mIdent, aBuffer, mSymbol);
// remove the trailing quote character
aBuffer.Truncate(aBuffer.Length() - 1);
break;
case eCSSToken_String:
nsStyleUtil::AppendEscapedCSSString(mIdent, aBuffer, mSymbol);
break;
case eCSSToken_Symbol:
aBuffer.Append(mSymbol);
break;
case eCSSToken_Whitespace:
aBuffer.Append(' ');
break;
case eCSSToken_HTMLComment:
case eCSSToken_URange:
aBuffer.Append(mIdent);
break;
case eCSSToken_Includes:
aBuffer.AppendLiteral("~=");
break;
case eCSSToken_Dashmatch:
aBuffer.AppendLiteral("|=");
break;
case eCSSToken_Beginsmatch:
aBuffer.AppendLiteral("^=");
break;
case eCSSToken_Endsmatch:
aBuffer.AppendLiteral("$=");
break;
case eCSSToken_Containsmatch:
aBuffer.AppendLiteral("*=");
break;
default:
NS_ERROR("invalid token type");
break;
}
}
/* nsCSSScanner methods. */
nsCSSScanner::nsCSSScanner(const nsAString& aBuffer, uint32_t aLineNumber)
: mBuffer(aBuffer.BeginReading())
, mOffset(0)
, mCount(aBuffer.Length())
, mLineNumber(aLineNumber)
, mLineOffset(0)
, mTokenLineNumber(aLineNumber)
, mTokenLineOffset(0)
, mTokenOffset(0)
, mRecordStartOffset(0)
, mEOFCharacters(eEOFCharacters_None)
, mReporter(nullptr)
, mSVGMode(false)
, mRecording(false)
, mSeenBadToken(false)
, mSeenVariableReference(false)
{
MOZ_COUNT_CTOR(nsCSSScanner);
}
nsCSSScanner::~nsCSSScanner()
{
MOZ_COUNT_DTOR(nsCSSScanner);
}
void
nsCSSScanner::StartRecording()
{
MOZ_ASSERT(!mRecording, "already started recording");
mRecording = true;
mRecordStartOffset = mOffset;
}
void
nsCSSScanner::StopRecording()
{
MOZ_ASSERT(mRecording, "haven't started recording");
mRecording = false;
}
void
nsCSSScanner::StopRecording(nsString& aBuffer)
{
MOZ_ASSERT(mRecording, "haven't started recording");
mRecording = false;
aBuffer.Append(mBuffer + mRecordStartOffset,
mOffset - mRecordStartOffset);
}
uint32_t
nsCSSScanner::RecordingLength() const
{
MOZ_ASSERT(mRecording, "haven't started recording");
return mOffset - mRecordStartOffset;
}
#ifdef DEBUG
bool
nsCSSScanner::IsRecording() const
{
return mRecording;
}
#endif
nsDependentSubstring
nsCSSScanner::GetCurrentLine() const
{
uint32_t end = mTokenOffset;
while (end < mCount && !IsVertSpace(mBuffer[end])) {
end++;
}
return nsDependentSubstring(mBuffer + mTokenLineOffset,
mBuffer + end);
}
/**
* Return the raw UTF-16 code unit at position |mOffset + n| within
* the read buffer. If that is beyond the end of the buffer, returns
* -1 to indicate end of input.
*/
inline int32_t
nsCSSScanner::Peek(uint32_t n)
{
if (mOffset + n >= mCount) {
return -1;
}
return mBuffer[mOffset + n];
}
/**
* Advance |mOffset| over |n| code units. Advance(0) is a no-op.
* If |n| is greater than the distance to end of input, will silently
* stop at the end. May not be used to advance over a line boundary;
* AdvanceLine() must be used instead.
*/
inline void
nsCSSScanner::Advance(uint32_t n)
{
#ifdef DEBUG
while (mOffset < mCount && n > 0) {
MOZ_ASSERT(!IsVertSpace(mBuffer[mOffset]),
"may not Advance() over a line boundary");
mOffset++;
n--;
}
#else
if (mOffset + n >= mCount || mOffset + n < mOffset)
mOffset = mCount;
else
mOffset += n;
#endif
}
/**
* Advance |mOffset| over a line boundary.
*/
void
nsCSSScanner::AdvanceLine()
{
MOZ_ASSERT(IsVertSpace(mBuffer[mOffset]),
"may not AdvanceLine() over a horizontal character");
// Advance over \r\n as a unit.
if (mBuffer[mOffset] == '\r' && mOffset + 1 < mCount &&
mBuffer[mOffset+1] == '\n')
mOffset += 2;
else
mOffset += 1;
// 0 is a magical line number meaning that we don't know (i.e., script)
if (mLineNumber != 0)
mLineNumber++;
mLineOffset = mOffset;
}
/**
* Back up |mOffset| over |n| code units. Backup(0) is a no-op.
* If |n| is greater than the distance to beginning of input, will
* silently stop at the beginning. May not be used to back up over a
* line boundary.
*/
void
nsCSSScanner::Backup(uint32_t n)
{
#ifdef DEBUG
while (mOffset > 0 && n > 0) {
MOZ_ASSERT(!IsVertSpace(mBuffer[mOffset-1]),
"may not Backup() over a line boundary");
mOffset--;
n--;
}
#else
if (mOffset < n)
mOffset = 0;
else
mOffset -= n;
#endif
}
void
nsCSSScanner::SavePosition(nsCSSScannerPosition& aState)
{
aState.mOffset = mOffset;
aState.mLineNumber = mLineNumber;
aState.mLineOffset = mLineOffset;
aState.mTokenLineNumber = mTokenLineNumber;
aState.mTokenLineOffset = mTokenLineOffset;
aState.mTokenOffset = mTokenOffset;
aState.mInitialized = true;
}
void
nsCSSScanner::RestoreSavedPosition(const nsCSSScannerPosition& aState)
{
MOZ_ASSERT(aState.mInitialized, "have not saved state");
if (aState.mInitialized) {
mOffset = aState.mOffset;
mLineNumber = aState.mLineNumber;
mLineOffset = aState.mLineOffset;
mTokenLineNumber = aState.mTokenLineNumber;
mTokenLineOffset = aState.mTokenLineOffset;
mTokenOffset = aState.mTokenOffset;
}
}
/**
* Skip over a sequence of whitespace characters (vertical or
* horizontal) starting at the current read position.
*/
void
nsCSSScanner::SkipWhitespace()
{
for (;;) {
int32_t ch = Peek();
if (!IsWhitespace(ch)) { // EOF counts as non-whitespace
break;
}
if (IsVertSpace(ch)) {
AdvanceLine();
} else {
Advance();
}
}
}
/**
* Skip over one CSS comment starting at the current read position.
*/
void
nsCSSScanner::SkipComment()
{
MOZ_ASSERT(Peek() == '/' && Peek(1) == '*', "should not have been called");
Advance(2);
for (;;) {
int32_t ch = Peek();
if (ch < 0) {
if (mReporter)
mReporter->ReportUnexpectedEOF("PECommentEOF");
SetEOFCharacters(eEOFCharacters_Asterisk | eEOFCharacters_Slash);
return;
}
if (ch == '*') {
Advance();
ch = Peek();
if (ch < 0) {
if (mReporter)
mReporter->ReportUnexpectedEOF("PECommentEOF");
SetEOFCharacters(eEOFCharacters_Slash);
return;
}
if (ch == '/') {
Advance();
return;
}
} else if (IsVertSpace(ch)) {
AdvanceLine();
} else {
Advance();
}
}
}
/**
* If there is a valid escape sequence starting at the current read
* position, consume it, decode it, append the result to |aOutput|,
* and return true. Otherwise, consume nothing, leave |aOutput|
* unmodified, and return false. If |aInString| is true, accept the
* additional form of escape sequence allowed within string-like tokens.
*/
bool
nsCSSScanner::GatherEscape(nsString& aOutput, bool aInString)
{
MOZ_ASSERT(Peek() == '\\', "should not have been called");
int32_t ch = Peek(1);
if (ch < 0) {
// If we are in a string (or a url() containing a string), we want to drop
// the backslash on the floor. Otherwise, we want to treat it as a U+FFFD
// character.
Advance();
if (aInString) {
SetEOFCharacters(eEOFCharacters_DropBackslash);
} else {
aOutput.Append(UCS2_REPLACEMENT_CHAR);
SetEOFCharacters(eEOFCharacters_ReplacementChar);
}
return true;
}
if (IsVertSpace(ch)) {
if (aInString) {
// In strings (and in url() containing a string), escaped
// newlines are completely removed, to allow splitting over
// multiple lines.
Advance();
AdvanceLine();
return true;
}
// Outside of strings, backslash followed by a newline is not an escape.
return false;
}
if (!IsHexDigit(ch)) {
// "Any character (except a hexadecimal digit, linefeed, carriage
// return, or form feed) can be escaped with a backslash to remove
// its special meaning." -- CSS2.1 section 4.1.3
Advance(2);
if (ch == 0) {
aOutput.Append(UCS2_REPLACEMENT_CHAR);
} else {
aOutput.Append(ch);
}
return true;
}
// "[at most six hexadecimal digits following a backslash] stand
// for the ISO 10646 character with that number, which must not be
// zero. (It is undefined in CSS 2.1 what happens if a style sheet
// does contain a character with Unicode codepoint zero.)"
// -- CSS2.1 section 4.1.3
// At this point we know we have \ followed by at least one
// hexadecimal digit, therefore the escape sequence is valid and we
// can go ahead and consume the backslash.
Advance();
uint32_t val = 0;
int i = 0;
do {
val = val * 16 + HexDigitValue(ch);
i++;
Advance();
ch = Peek();
} while (i < 6 && IsHexDigit(ch));
// "Interpret the hex digits as a hexadecimal number. If this number is zero,
// or is greater than the maximum allowed codepoint, return U+FFFD
// REPLACEMENT CHARACTER" -- CSS Syntax Level 3
if (MOZ_UNLIKELY(val == 0)) {
aOutput.Append(UCS2_REPLACEMENT_CHAR);
} else {
AppendUCS4ToUTF16(ENSURE_VALID_CHAR(val), aOutput);
}
// Consume exactly one whitespace character after a
// hexadecimal escape sequence.
if (IsVertSpace(ch)) {
AdvanceLine();
} else if (IsHorzSpace(ch)) {
Advance();
}
return true;
}
/**
* Consume a run of "text" beginning with the current read position,
* consisting of characters in the class |aClass| (which must be a
* suitable argument to IsOpenCharClass) plus escape sequences.
* Append the text to |aText|, after decoding escape sequences.
*
* Returns true if at least one character was appended to |aText|,
* false otherwise.
*/
bool
nsCSSScanner::GatherText(uint8_t aClass, nsString& aText)
{
// This is all of the character classes currently used with
// GatherText. If you have a need to use this function with a
// different class, go ahead and add it.
MOZ_ASSERT(aClass == IS_STRING ||
aClass == IS_IDCHAR ||
aClass == IS_URL_CHAR,
"possibly-inappropriate character class");
uint32_t start = mOffset;
bool inString = aClass == IS_STRING;
for (;;) {
// Consume runs of unescaped characters in one go.
uint32_t n = mOffset;
while (n < mCount && IsOpenCharClass(mBuffer[n], aClass)) {
n++;
}
if (n > mOffset) {
aText.Append(&mBuffer[mOffset], n - mOffset);
mOffset = n;
}
if (n == mCount) {
break;
}
int32_t ch = Peek();
MOZ_ASSERT(!IsOpenCharClass(ch, aClass),
"should not have exited the inner loop");
if (ch == 0) {
Advance();
aText.Append(UCS2_REPLACEMENT_CHAR);
continue;
}
if (ch != '\\') {
break;
}
if (!GatherEscape(aText, inString)) {
break;
}
}
return mOffset > start;
}
/**
* Scan an Ident token. This also handles Function and URL tokens,
* both of which begin indistinguishably from an identifier. It can
* produce a Symbol token when an apparent identifier actually led
* into an invalid escape sequence.
*/
bool
nsCSSScanner::ScanIdent(nsCSSToken& aToken)
{
if (MOZ_UNLIKELY(!GatherText(IS_IDCHAR, aToken.mIdent))) {
MOZ_ASSERT(Peek() == '\\',
"unexpected IsIdentStart character that did not begin an ident");
aToken.mSymbol = Peek();
Advance();
return true;
}
if (MOZ_LIKELY(Peek() != '(')) {
aToken.mType = eCSSToken_Ident;
return true;
}
Advance();
aToken.mType = eCSSToken_Function;
if (aToken.mIdent.LowerCaseEqualsLiteral("url")) {
NextURL(aToken);
} else if (aToken.mIdent.LowerCaseEqualsLiteral("var")) {
mSeenVariableReference = true;
}
return true;
}
/**
* Scan an AtKeyword token. Also handles production of Symbol when
* an '@' is not followed by an identifier.
*/
bool
nsCSSScanner::ScanAtKeyword(nsCSSToken& aToken)
{
MOZ_ASSERT(Peek() == '@', "should not have been called");
// Fall back for when '@' isn't followed by an identifier.
aToken.mSymbol = '@';
Advance();
int32_t ch = Peek();
if (StartsIdent(ch, Peek(1))) {
if (GatherText(IS_IDCHAR, aToken.mIdent)) {
aToken.mType = eCSSToken_AtKeyword;
}
}
return true;
}
/**
* Scan a Hash token. Handles the distinction between eCSSToken_ID
* and eCSSToken_Hash, and handles production of Symbol when a '#'
* is not followed by identifier characters.
*/
bool
nsCSSScanner::ScanHash(nsCSSToken& aToken)
{
MOZ_ASSERT(Peek() == '#', "should not have been called");
// Fall back for when '#' isn't followed by identifier characters.
aToken.mSymbol = '#';
Advance();
int32_t ch = Peek();
if (IsIdentChar(ch) || ch == '\\') {
nsCSSTokenType type =
StartsIdent(ch, Peek(1)) ? eCSSToken_ID : eCSSToken_Hash;
aToken.mIdent.SetLength(0);
if (GatherText(IS_IDCHAR, aToken.mIdent)) {
aToken.mType = type;
}
}
return true;
}
/**
* Scan a Number, Percentage, or Dimension token (all of which begin
* like a Number). Can produce a Symbol when a '.' is not followed by
* digits, or when '+' or '-' are not followed by either a digit or a
* '.' and then a digit. Can also produce a HTMLComment when it
* encounters '-->'.
*/
bool
nsCSSScanner::ScanNumber(nsCSSToken& aToken)
{
int32_t c = Peek();
#ifdef DEBUG
{
int32_t c2 = Peek(1);
int32_t c3 = Peek(2);
MOZ_ASSERT(IsDigit(c) ||
(IsDigit(c2) && (c == '.' || c == '+' || c == '-')) ||
(IsDigit(c3) && (c == '+' || c == '-') && c2 == '.'),
"should not have been called");
}
#endif
// Sign of the mantissa (-1 or 1).
int32_t sign = c == '-' ? -1 : 1;
// Absolute value of the integer part of the mantissa. This is a double so
// we don't run into overflow issues for consumers that only care about our
// floating-point value while still being able to express the full int32_t
// range for consumers who want integers.
double intPart = 0;
// Fractional part of the mantissa. This is a double so that when we convert
// to float at the end we'll end up rounding to nearest float instead of
// truncating down (as we would if fracPart were a float and we just
// effectively lost the last several digits).
double fracPart = 0;
// Absolute value of the power of 10 that we should multiply by (only
// relevant for numbers in scientific notation). Has to be a signed integer,
// because multiplication of signed by unsigned converts the unsigned to
// signed, so if we plan to actually multiply by expSign...
int32_t exponent = 0;
// Sign of the exponent.
int32_t expSign = 1;
aToken.mHasSign = (c == '+' || c == '-');
if (aToken.mHasSign) {
Advance();
c = Peek();
}
bool gotDot = (c == '.');
if (!gotDot) {
// Scan the integer part of the mantissa.
MOZ_ASSERT(IsDigit(c), "should have been excluded by logic above");
do {
intPart = 10*intPart + DecimalDigitValue(c);
Advance();
c = Peek();
} while (IsDigit(c));
gotDot = (c == '.') && IsDigit(Peek(1));
}
if (gotDot) {
// Scan the fractional part of the mantissa.
Advance();
c = Peek();
MOZ_ASSERT(IsDigit(c), "should have been excluded by logic above");
// Power of ten by which we need to divide our next digit
double divisor = 10;
do {
fracPart += DecimalDigitValue(c) / divisor;
divisor *= 10;
Advance();
c = Peek();
} while (IsDigit(c));
}
bool gotE = false;
if (c == 'e' || c == 'E') {
int32_t expSignChar = Peek(1);
int32_t nextChar = Peek(2);
if (IsDigit(expSignChar) ||
((expSignChar == '-' || expSignChar == '+') && IsDigit(nextChar))) {
gotE = true;
if (expSignChar == '-') {
expSign = -1;
}
Advance(); // consumes the E
if (expSignChar == '-' || expSignChar == '+') {
Advance();
c = nextChar;
} else {
c = expSignChar;
}
MOZ_ASSERT(IsDigit(c), "should have been excluded by logic above");
do {
exponent = 10*exponent + DecimalDigitValue(c);
Advance();
c = Peek();
} while (IsDigit(c));
}
}
nsCSSTokenType type = eCSSToken_Number;
// Set mIntegerValid for all cases (except %, below) because we need
// it for the "2n" in :nth-child(2n).
aToken.mIntegerValid = false;
// Time to reassemble our number.
// Do all the math in double precision so it's truncated only once.
double value = sign * (intPart + fracPart);
if (gotE) {
// Explicitly cast expSign*exponent to double to avoid issues with
// overloaded pow() on Windows.
value *= pow(10.0, double(expSign * exponent));
} else if (!gotDot) {
// Clamp values outside of integer range.
if (sign > 0) {
aToken.mInteger = int32_t(std::min(intPart, double(INT32_MAX)));
} else {
aToken.mInteger = int32_t(std::max(-intPart, double(INT32_MIN)));
}
aToken.mIntegerValid = true;
}
nsString& ident = aToken.mIdent;
// Check for Dimension and Percentage tokens.
if (c >= 0) {
if (StartsIdent(c, Peek(1))) {
if (GatherText(IS_IDCHAR, ident)) {
type = eCSSToken_Dimension;
}
} else if (c == '%') {
Advance();
type = eCSSToken_Percentage;
value = value / 100.0f;
aToken.mIntegerValid = false;
}
}
aToken.mNumber = value;
aToken.mType = type;
return true;
}
/**
* Scan a string constant ('foo' or "foo"). Will always produce
* either a String or a Bad_String token; the latter occurs when the
* close quote is missing. Always returns true (for convenience in Next()).
*/
bool
nsCSSScanner::ScanString(nsCSSToken& aToken)
{
int32_t aStop = Peek();
MOZ_ASSERT(aStop == '"' || aStop == '\'', "should not have been called");
aToken.mType = eCSSToken_String;
aToken.mSymbol = char16_t(aStop); // Remember how it's quoted.
Advance();
for (;;) {
GatherText(IS_STRING, aToken.mIdent);
int32_t ch = Peek();
if (ch == -1) {
AddEOFCharacters(aStop == '"' ? eEOFCharacters_DoubleQuote :
eEOFCharacters_SingleQuote);
break; // EOF ends a string token with no error.
}
if (ch == aStop) {
Advance();
break;
}
// Both " and ' are excluded from IS_STRING.
if (ch == '"' || ch == '\'') {
aToken.mIdent.Append(ch);
Advance();
continue;
}
mSeenBadToken = true;
aToken.mType = eCSSToken_Bad_String;
if (mReporter)
mReporter->ReportUnexpected("SEUnterminatedString", aToken);
break;
}
return true;
}
/**
* Scan a unicode-range token. These match the regular expression
*
* u\+[0-9a-f?]{1,6}(-[0-9a-f]{1,6})?
*
* However, some such tokens are "invalid". There are three valid forms:
*
* u+[0-9a-f]{x} 1 <= x <= 6
* u+[0-9a-f]{x}\?{y} 1 <= x+y <= 6
* u+[0-9a-f]{x}-[0-9a-f]{y} 1 <= x <= 6, 1 <= y <= 6
*
* All unicode-range tokens have their text recorded in mIdent; valid ones
* are also decoded into mInteger and mInteger2, and mIntegerValid is set.
* Note that this does not validate the numeric range, only the syntactic
* form.
*/
bool
nsCSSScanner::ScanURange(nsCSSToken& aResult)
{
int32_t intro1 = Peek();
int32_t intro2 = Peek(1);
int32_t ch = Peek(2);
MOZ_ASSERT((intro1 == 'u' || intro1 == 'U') &&
intro2 == '+' &&
(IsHexDigit(ch) || ch == '?'),
"should not have been called");
aResult.mIdent.Append(intro1);
aResult.mIdent.Append(intro2);
Advance(2);
bool valid = true;
bool haveQues = false;
uint32_t low = 0;
uint32_t high = 0;
int i = 0;
do {
aResult.mIdent.Append(ch);
if (IsHexDigit(ch)) {
if (haveQues) {
valid = false; // All question marks should be at the end.
}
low = low*16 + HexDigitValue(ch);
high = high*16 + HexDigitValue(ch);
} else {
haveQues = true;
low = low*16 + 0x0;
high = high*16 + 0xF;
}
i++;
Advance();
ch = Peek();
} while (i < 6 && (IsHexDigit(ch) || ch == '?'));
if (ch == '-' && IsHexDigit(Peek(1))) {
if (haveQues) {
valid = false;
}
aResult.mIdent.Append(ch);
Advance();
ch = Peek();
high = 0;
i = 0;
do {
aResult.mIdent.Append(ch);
high = high*16 + HexDigitValue(ch);
i++;
Advance();
ch = Peek();
} while (i < 6 && IsHexDigit(ch));
}
aResult.mInteger = low;
aResult.mInteger2 = high;
aResult.mIntegerValid = valid;
aResult.mType = eCSSToken_URange;
return true;
}
#ifdef DEBUG
/* static */ void
nsCSSScanner::AssertEOFCharactersValid(uint32_t c)
{
MOZ_ASSERT(c == eEOFCharacters_None ||
c == eEOFCharacters_ReplacementChar ||
c == eEOFCharacters_Slash ||
c == (eEOFCharacters_Asterisk |
eEOFCharacters_Slash) ||
c == eEOFCharacters_DoubleQuote ||
c == eEOFCharacters_SingleQuote ||
c == (eEOFCharacters_DropBackslash |
eEOFCharacters_DoubleQuote) ||
c == (eEOFCharacters_DropBackslash |
eEOFCharacters_SingleQuote) ||
c == eEOFCharacters_CloseParen ||
c == (eEOFCharacters_ReplacementChar |
eEOFCharacters_CloseParen) ||
c == (eEOFCharacters_DoubleQuote |
eEOFCharacters_CloseParen) ||
c == (eEOFCharacters_SingleQuote |
eEOFCharacters_CloseParen) ||
c == (eEOFCharacters_DropBackslash |
eEOFCharacters_DoubleQuote |
eEOFCharacters_CloseParen) ||
c == (eEOFCharacters_DropBackslash |
eEOFCharacters_SingleQuote |
eEOFCharacters_CloseParen),
"invalid EOFCharacters value");
}
#endif
void
nsCSSScanner::SetEOFCharacters(uint32_t aEOFCharacters)
{
mEOFCharacters = EOFCharacters(aEOFCharacters);
}
void
nsCSSScanner::AddEOFCharacters(uint32_t aEOFCharacters)
{
mEOFCharacters = EOFCharacters(mEOFCharacters | aEOFCharacters);
}
static const char16_t kImpliedEOFCharacters[] = {
UCS2_REPLACEMENT_CHAR, '*', '/', '"', '\'', ')', 0
};
/* static */ void
nsCSSScanner::AppendImpliedEOFCharacters(EOFCharacters aEOFCharacters,
nsAString& aResult)
{
// First, ignore eEOFCharacters_DropBackslash.
uint32_t c = aEOFCharacters >> 1;
// All of the remaining EOFCharacters bits represent appended characters,
// and the bits are in the order that they need appending.
for (const char16_t* p = kImpliedEOFCharacters; *p && c; p++, c >>= 1) {
if (c & 1) {
aResult.Append(*p);
}
}
MOZ_ASSERT(c == 0, "too many bits in mEOFCharacters");
}
/**
* Consume the part of an URL token after the initial 'url('. Caller
* is assumed to have consumed 'url(' already. Will always produce
* either an URL or a Bad_URL token.
*
* Exposed for use by nsCSSParser::ParseMozDocumentRule, which applies
* the special lexical rules for URL tokens in a nonstandard context.
*/
void
nsCSSScanner::NextURL(nsCSSToken& aToken)
{
SkipWhitespace();
// aToken.mIdent may be "url" at this point; clear that out
aToken.mIdent.Truncate();
int32_t ch = Peek();
// Do we have a string?
if (ch == '"' || ch == '\'') {
ScanString(aToken);
if (MOZ_UNLIKELY(aToken.mType == eCSSToken_Bad_String)) {
aToken.mType = eCSSToken_Bad_URL;
return;
}
MOZ_ASSERT(aToken.mType == eCSSToken_String, "unexpected token type");
} else {
// Otherwise, this is the start of a non-quoted url (which may be empty).
aToken.mSymbol = char16_t(0);
GatherText(IS_URL_CHAR, aToken.mIdent);
}
// Consume trailing whitespace and then look for a close parenthesis.
SkipWhitespace();
ch = Peek();
// ch can be less than zero indicating EOF
if (MOZ_LIKELY(ch < 0 || ch == ')')) {
Advance();
aToken.mType = eCSSToken_URL;
if (ch < 0) {
AddEOFCharacters(eEOFCharacters_CloseParen);
}
} else {
mSeenBadToken = true;
aToken.mType = eCSSToken_Bad_URL;
}
}
/**
* Primary scanner entry point. Consume one token and fill in
* |aToken| accordingly. Will skip over any number of comments first,
* and will also skip over rather than return whitespace and comment
* tokens, depending on the value of |aSkip|.
*
* Returns true if it successfully consumed a token, false if EOF has
* been reached. Will always advance the current read position by at
* least one character unless called when already at EOF.
*/
bool
nsCSSScanner::Next(nsCSSToken& aToken, nsCSSScannerExclude aSkip)
{
int32_t ch;
// do this here so we don't have to do it in dozens of other places
aToken.mIdent.Truncate();
aToken.mType = eCSSToken_Symbol;
for (;;) {
// Consume any number of comments, and possibly also whitespace tokens,
// in between other tokens.
mTokenOffset = mOffset;
mTokenLineOffset = mLineOffset;
mTokenLineNumber = mLineNumber;
ch = Peek();
if (IsWhitespace(ch)) {
SkipWhitespace();
if (aSkip != eCSSScannerExclude_WhitespaceAndComments) {
aToken.mType = eCSSToken_Whitespace;
return true;
}
continue; // start again at the beginning
}
if (ch == '/' && !IsSVGMode() && Peek(1) == '*') {
SkipComment();
if (aSkip == eCSSScannerExclude_None) {
aToken.mType = eCSSToken_Comment;
return true;
}
continue; // start again at the beginning
}
break;
}
// EOF
if (ch < 0) {
return false;
}
// 'u' could be UNICODE-RANGE or an identifier-family token
if (ch == 'u' || ch == 'U') {
int32_t c2 = Peek(1);
int32_t c3 = Peek(2);
if (c2 == '+' && (IsHexDigit(c3) || c3 == '?')) {
return ScanURange(aToken);
}
return ScanIdent(aToken);
}
// identifier family
if (IsIdentStart(ch)) {
return ScanIdent(aToken);
}
// number family
if (IsDigit(ch)) {
return ScanNumber(aToken);
}
if (ch == '.' && IsDigit(Peek(1))) {
return ScanNumber(aToken);
}
if (ch == '+') {
int32_t c2 = Peek(1);
if (IsDigit(c2) || (c2 == '.' && IsDigit(Peek(2)))) {
return ScanNumber(aToken);
}
}
// '-' can start an identifier-family token, a number-family token,
// or an HTML-comment
if (ch == '-') {
int32_t c2 = Peek(1);
int32_t c3 = Peek(2);
if (IsIdentStart(c2) || (c2 == '-' && c3 != '>')) {
return ScanIdent(aToken);
}
if (IsDigit(c2) || (c2 == '.' && IsDigit(c3))) {
return ScanNumber(aToken);
}
if (c2 == '-' && c3 == '>') {
Advance(3);
aToken.mType = eCSSToken_HTMLComment;
aToken.mIdent.AssignLiteral("-->");
return true;
}
}
// the other HTML-comment token
if (ch == '<' && Peek(1) == '!' && Peek(2) == '-' && Peek(3) == '-') {
Advance(4);
aToken.mType = eCSSToken_HTMLComment;
aToken.mIdent.AssignLiteral("<!--");
return true;
}
// AT_KEYWORD
if (ch == '@') {
return ScanAtKeyword(aToken);
}
// HASH
if (ch == '#') {
return ScanHash(aToken);
}
// STRING
if (ch == '"' || ch == '\'') {
return ScanString(aToken);
}
// Match operators: ~= |= ^= $= *=
nsCSSTokenType opType = MatchOperatorType(ch);
if (opType != eCSSToken_Symbol && Peek(1) == '=') {
aToken.mType = opType;
Advance(2);
return true;
}
// Otherwise, a symbol (DELIM).
aToken.mSymbol = ch;
Advance();
return true;
}
/* nsCSSGridTemplateAreaScanner methods. */
nsCSSGridTemplateAreaScanner::nsCSSGridTemplateAreaScanner(const nsAString& aBuffer)
: mBuffer(aBuffer.BeginReading())
, mOffset(0)
, mCount(aBuffer.Length())
{
}
bool
nsCSSGridTemplateAreaScanner::Next(nsCSSGridTemplateAreaToken& aTokenResult)
{
int32_t ch;
// Skip whitespace
do {
if (mOffset >= mCount) {
return false;
}
ch = mBuffer[mOffset];
mOffset++;
} while (IsWhitespace(ch));
if (IsOpenCharClass(ch, IS_IDCHAR)) {
// Named cell token
uint32_t start = mOffset - 1; // offset of |ch|
while (mOffset < mCount && IsOpenCharClass(mBuffer[mOffset], IS_IDCHAR)) {
mOffset++;
}
aTokenResult.mName.Assign(&mBuffer[start], mOffset - start);
aTokenResult.isTrash = false;
} else if (ch == '.') {
// Null cell token
// Skip any other '.'
while (mOffset < mCount && mBuffer[mOffset] == '.') {
mOffset++;
}
aTokenResult.mName.Truncate();
aTokenResult.isTrash = false;
} else {
// Trash token
aTokenResult.isTrash = true;
}
return true;
}
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