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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 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#include "nsCSSScanner.h"
#include "nsIInputStream.h"
#include "nsIUnicharInputStream.h"
#include "nsString.h"
#include "nsCRT.h"
#ifdef NS_DEBUG
static char* kNullPointer = "null pointer";
#endif
// Don't bother collecting whitespace characters in token's mIdent buffer
#undef COLLECT_WHITESPACE
#define BUFFER_SIZE 256
static const PRUnichar CSS_ESCAPE = PRUnichar('\\');
static const PRUint8 IS_LATIN1 = 0x01;
static const PRUint8 IS_DIGIT = 0x02;
static const PRUint8 IS_HEX_DIGIT = 0x04;
static const PRUint8 IS_ALPHA = 0x08;
static const PRUint8 START_IDENT = 0x10;
static const PRUint8 IS_IDENT = 0x20;
static const PRUint8 IS_WHITESPACE = 0x40;
static PRUint8* gLexTable;
static void BuildLexTable()
{
PRUint8* lt = new PRUint8[256];
nsCRT::zero(lt, 256);
gLexTable = lt;
int i;
lt[CSS_ESCAPE] = START_IDENT;
lt['-'] |= IS_IDENT;
lt['_'] |= IS_IDENT;
// XXX add in other whitespace chars
lt[' '] |= IS_WHITESPACE; // space
lt['\t'] |= IS_WHITESPACE; // horizontal tab
lt['\v'] |= IS_WHITESPACE; // vertical tab
lt['\r'] |= IS_WHITESPACE; // carriage return
lt['\n'] |= IS_WHITESPACE; // line feed
lt['\f'] |= IS_WHITESPACE; // form feed
for (i = 161; i <= 255; i++) {
lt[i] |= IS_LATIN1 | IS_IDENT | START_IDENT;
}
for (i = '0'; i <= '9'; i++) {
lt[i] |= IS_DIGIT | IS_HEX_DIGIT | IS_IDENT;
}
for (i = 'A'; i <= 'Z'; i++) {
if ((i >= 'A') && (i <= 'F')) {
lt[i] |= IS_HEX_DIGIT;
lt[i+32] |= IS_HEX_DIGIT;
}
lt[i] |= IS_ALPHA | IS_IDENT | START_IDENT;
lt[i+32] |= IS_ALPHA | IS_IDENT | START_IDENT;
}
}
nsCSSToken::nsCSSToken()
{
mType = eCSSToken_Symbol;
}
void
nsCSSToken::AppendToString(nsString& aBuffer)
{
switch (mType) {
case eCSSToken_AtKeyword:
aBuffer.Append(PRUnichar('@')); // fall through intentional
case eCSSToken_Ident:
case eCSSToken_WhiteSpace:
case eCSSToken_Function:
case eCSSToken_URL:
case eCSSToken_InvalidURL:
case eCSSToken_HTMLComment:
aBuffer.Append(mIdent);
break;
case eCSSToken_Number:
if (mIntegerValid) {
aBuffer.Append(mInteger, 10);
}
else {
aBuffer.Append(mNumber);
}
break;
case eCSSToken_Percentage:
if (mIntegerValid) {
aBuffer.Append(mInteger, 10);
}
else {
aBuffer.Append(mNumber);
}
aBuffer.Append(PRUnichar('%'));
break;
case eCSSToken_Dimension:
if (mIntegerValid) {
aBuffer.Append(mInteger, 10);
}
else {
aBuffer.Append(mNumber);
}
aBuffer.Append(mIdent);
break;
case eCSSToken_String:
aBuffer.Append(mSymbol);
aBuffer.Append(mIdent); // fall through intentional
case eCSSToken_Symbol:
aBuffer.Append(mSymbol);
break;
case eCSSToken_ID:
aBuffer.Append(PRUnichar('#'));
aBuffer.Append(mIdent);
break;
default:
NS_ERROR("invalid token type");
break;
}
}
nsCSSScanner::nsCSSScanner()
{
if (nsnull == gLexTable) {
// XXX need a monitor
BuildLexTable();
}
mInput = nsnull;
mBuffer = new PRUnichar[BUFFER_SIZE];
mOffset = 0;
mCount = 0;
mPushback = mLocalPushback;
mPushbackCount = 0;
mPushbackSize = 4;
}
nsCSSScanner::~nsCSSScanner()
{
Close();
if (nsnull != mBuffer) {
delete [] mBuffer;
mBuffer = nsnull;
}
if (mLocalPushback != mPushback) {
delete [] mPushback;
}
}
void nsCSSScanner::Init(nsIUnicharInputStream* aInput)
{
NS_PRECONDITION(nsnull != aInput, kNullPointer);
Close();
mInput = aInput;
NS_IF_ADDREF(aInput);
}
void nsCSSScanner::Close()
{
NS_IF_RELEASE(mInput);
}
// Returns -1 on error or eof
PRInt32 nsCSSScanner::Read(PRInt32& aErrorCode)
{
PRInt32 rv;
if (0 < mPushbackCount) {
rv = PRInt32(mPushback[--mPushbackCount]);
} else {
if (mCount < 0) {
return -1;
}
if (mOffset == mCount) {
mOffset = 0;
aErrorCode = mInput->Read(mBuffer, 0, BUFFER_SIZE, (PRUint32*)&mCount);
if (NS_FAILED(aErrorCode) || mCount == 0) {
mCount = 0;
return -1;
}
}
rv = PRInt32(mBuffer[mOffset++]);
}
mLastRead = rv;
//printf("Read => %x\n", rv);
return rv;
}
PRInt32 nsCSSScanner::Peek(PRInt32& aErrorCode)
{
if (0 == mPushbackCount) {
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
return -1;
}
mPushback[0] = PRUnichar(ch);
mPushbackCount++;
}
//printf("Peek => %x\n", mLookAhead);
return PRInt32(mPushback[mPushbackCount - 1]);
}
void nsCSSScanner::Unread()
{
NS_PRECONDITION((mLastRead >= 0), "double pushback");
Pushback(PRUnichar(mLastRead));
mLastRead = -1;
}
void nsCSSScanner::Pushback(PRUnichar aChar)
{
if (mPushbackCount == mPushbackSize) { // grow buffer
PRUnichar* newPushback = new PRUnichar[mPushbackSize + 4];
if (nsnull == newPushback) {
return;
}
mPushbackSize += 4;
nsCRT::memcpy(newPushback, mPushback, sizeof(PRUnichar) * mPushbackCount);
if (mPushback != mLocalPushback) {
delete [] mPushback;
}
mPushback = newPushback;
}
mPushback[mPushbackCount++] = aChar;
}
PRBool nsCSSScanner::LookAhead(PRInt32& aErrorCode, PRUnichar aChar)
{
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
return PR_FALSE;
}
if (ch == aChar) {
return PR_TRUE;
}
Unread();
return PR_FALSE;
}
PRBool nsCSSScanner::EatWhiteSpace(PRInt32& aErrorCode)
{
PRBool eaten = PR_FALSE;
for (;;) {
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
break;
}
if ((ch == ' ') || (ch == '\n') || (ch == '\r') || (ch == '\t')) {
eaten = PR_TRUE;
continue;
}
Unread();
break;
}
return eaten;
}
PRBool nsCSSScanner::EatNewline(PRInt32& aErrorCode)
{
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
return PR_FALSE;
}
PRBool eaten = PR_FALSE;
if (ch == '\r') {
eaten = PR_TRUE;
ch = Peek(aErrorCode);
if (ch == '\n') {
(void) Read(aErrorCode);
}
} else if (ch == '\n') {
eaten = PR_TRUE;
} else {
Unread();
}
return eaten;
}
PRBool nsCSSScanner::Next(PRInt32& aErrorCode, nsCSSToken& aToken)
{
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
return PR_FALSE;
}
if (ch < 256) {
PRUint8* lexTable = gLexTable;
// IDENT
if ((lexTable[ch] & START_IDENT) != 0) {
return ParseIdent(aErrorCode, ch, aToken);
}
if (ch == '-') { // possible ident
PRInt32 nextChar = Peek(aErrorCode);
if ((0 <= nextChar) && (0 != (lexTable[nextChar] & START_IDENT))) {
return ParseIdent(aErrorCode, ch, aToken);
}
}
// AT_KEYWORD
if (ch == '@') {
PRInt32 nextChar = Peek(aErrorCode);
if ((nextChar >= 0) && (nextChar <= 255)) {
if ((lexTable[nextChar] & START_IDENT) != 0) {
return ParseAtKeyword(aErrorCode, ch, aToken);
}
}
}
// NUMBER or DIM
if ((ch == '.') || (ch == '+') || (ch == '-')) {
PRInt32 nextChar = Peek(aErrorCode);
if ((nextChar >= 0) && (nextChar <= 255)) {
if ((lexTable[nextChar] & IS_DIGIT) != 0) {
return ParseNumber(aErrorCode, ch, aToken);
}
else if (('.' == nextChar) && ('.' != ch)) {
PRInt32 holdNext = Read(aErrorCode);
nextChar = Peek(aErrorCode);
if ((0 <= nextChar) && (nextChar <= 255)) {
if ((lexTable[nextChar] & IS_DIGIT) != 0) {
Pushback(holdNext);
return ParseNumber(aErrorCode, ch, aToken);
}
}
Pushback(holdNext);
}
}
}
if ((lexTable[ch] & IS_DIGIT) != 0) {
return ParseNumber(aErrorCode, ch, aToken);
}
// ID
if (ch == '#') {
return ParseID(aErrorCode, ch, aToken);
}
// STRING
if ((ch == '"') || (ch == '\'')) {
return ParseString(aErrorCode, ch, aToken);
}
// WS
if ((lexTable[ch] & IS_WHITESPACE) != 0) {
aToken.mType = eCSSToken_WhiteSpace;
aToken.mIdent.SetLength(0);
aToken.mIdent.Append(PRUnichar(ch));
(void) EatWhiteSpace(aErrorCode);
return PR_TRUE;
}
if (ch == '/') {
PRInt32 nextChar = Peek(aErrorCode);
if (nextChar == '*') {
(void) Read(aErrorCode);
aToken.mIdent.SetLength(0);
aToken.mIdent.Append(PRUnichar(ch));
aToken.mIdent.Append(PRUnichar(nextChar));
return ParseCComment(aErrorCode, aToken);
}
}
if (ch == '<') { // consume HTML comment tags as comments
PRInt32 nextChar = Peek(aErrorCode);
if (nextChar == '!') {
(void) Read(aErrorCode);
aToken.mType = eCSSToken_HTMLComment;
aToken.mIdent.SetLength(0);
aToken.mIdent.Append(PRUnichar(ch));
aToken.mIdent.Append(PRUnichar(nextChar));
nextChar = Peek(aErrorCode);
while ((0 < nextChar) && (nextChar == '-')) {
Read(aErrorCode);
aToken.mIdent.Append(PRUnichar(nextChar));
nextChar = Peek(aErrorCode);
}
return PR_TRUE;
}
}
if (ch == '-') { // check for HTML comment end
PRInt32 nextChar = Peek(aErrorCode);
if (nextChar == '-') {
PRInt32 dashCount = 1;
PRBool white = PR_FALSE;
while (nextChar == '-') {
(void) Read(aErrorCode);
dashCount++;
nextChar = Peek(aErrorCode);
}
if ((nextChar == ' ') || (nextChar == '\n') ||
(nextChar == '\r') || (nextChar == '\t')) {
EatWhiteSpace(aErrorCode);
white = PR_TRUE;
nextChar = Peek(aErrorCode);
}
if (nextChar == '>') { // HTML end
(void) Read(aErrorCode);
aToken.mType = eCSSToken_HTMLComment;
aToken.mIdent.SetLength(0);
while (0 < dashCount--) {
aToken.mIdent.Append('-');
}
if (white) {
aToken.mIdent.Append(' ');
}
aToken.mIdent.Append('>');
return PR_TRUE;
}
else { // wasn't an end comment, push it all back
if (white) {
Pushback(' ');
}
while (0 < --dashCount) {
Pushback('-');
}
}
}
}
}
aToken.mType = eCSSToken_Symbol;
aToken.mSymbol = ch;
return PR_TRUE;
}
PRBool nsCSSScanner::NextURL(PRInt32& aErrorCode, nsCSSToken& aToken)
{
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
return PR_FALSE;
}
if (ch < 256) {
PRUint8* lexTable = gLexTable;
// STRING
if ((ch == '"') || (ch == '\'')) {
return ParseString(aErrorCode, ch, aToken);
}
// WS
if ((lexTable[ch] & IS_WHITESPACE) != 0) {
aToken.mType = eCSSToken_WhiteSpace;
aToken.mIdent.SetLength(0);
aToken.mIdent.Append(PRUnichar(ch));
(void) EatWhiteSpace(aErrorCode);
return PR_TRUE;
}
if (ch == '/') {
PRInt32 nextChar = Peek(aErrorCode);
if (nextChar == '*') {
(void) Read(aErrorCode);
aToken.mIdent.SetLength(0);
aToken.mIdent.Append(PRUnichar(ch));
aToken.mIdent.Append(PRUnichar(nextChar));
return ParseCComment(aErrorCode, aToken);
}
}
// Process a url lexical token. A CSS1 url token can contain
// characters beyond identifier characters (e.g. '/', ':', etc.)
// Because of this the normal rules for tokenizing the input don't
// apply very well. To simplify the parser and relax some of the
// requirements on the scanner we parse url's here. If we find a
// malformed URL then we emit a token of type "InvalidURL" so that
// the CSS1 parser can ignore the invalid input. We attempt to eat
// the right amount of input data when an invalid URL is presented.
aToken.mType = eCSSToken_InvalidURL;
nsString& ident = aToken.mIdent;
ident.SetLength(0);
if (ch == ')') {
Pushback(ch);
// empty url spec: this is invalid
} else {
// start of a non-quoted url
Pushback(ch);
PRBool ok = PR_TRUE;
for (;;) {
ch = Read(aErrorCode);
if (ch < 0) break;
if (ch == CSS_ESCAPE) {
ch = ParseEscape(aErrorCode);
if (0 < ch) {
ident.Append(PRUnichar(ch));
}
} else if ((ch == '"') || (ch == '\'') || (ch == '(')) {
// This is an invalid URL spec
ok = PR_FALSE;
} else if ((256 >= ch) && ((gLexTable[ch] & IS_WHITESPACE) != 0)) {
// Whitespace is allowed at the end of the URL
(void) EatWhiteSpace(aErrorCode);
if (LookAhead(aErrorCode, ')')) {
Pushback(')'); // leave the closing symbol
// done!
break;
}
// Whitespace is followed by something other than a
// ")". This is an invalid url spec.
ok = PR_FALSE;
} else if (ch == ')') {
Unread();
// All done
break;
} else {
// A regular url character.
ident.Append(PRUnichar(ch));
}
}
// If the result of the above scanning is ok then change the token
// type to a useful one.
if (ok) {
aToken.mType = eCSSToken_URL;
}
}
}
return PR_TRUE;
}
PRInt32 nsCSSScanner::ParseEscape(PRInt32& aErrorCode)
{
PRUint8* lexTable = gLexTable;
PRInt32 ch = Peek(aErrorCode);
if (ch < 0) {
return CSS_ESCAPE;
}
if ((ch <= 255) && ((lexTable[ch] & IS_HEX_DIGIT) != 0)) {
PRInt32 rv = 0;
int i;
for (i = 0; i < 6; i++) { // up to six digits
ch = Read(aErrorCode);
if (ch < 0) {
// Whoops: error or premature eof
break;
}
if ((lexTable[ch] & IS_HEX_DIGIT) != 0) {
if ((lexTable[ch] & IS_DIGIT) != 0) {
rv = rv * 16 + (ch - '0');
} 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.
rv = rv * 16 + ((ch & 0x7) + 9);
}
}
else if ((lexTable[ch] & IS_WHITESPACE) != 0) { // single space ends escape
if (ch == '\r') { // if CR/LF, eat LF too
ch = Peek(aErrorCode);
if (ch == '\n') {
ch = Read(aErrorCode);
}
}
break;
}
else {
Unread();
break;
}
}
if (6 == i) { // look for trailing whitespace and eat it
ch = Peek(aErrorCode);
if ((0 <= ch) && (ch <= 255) &&
((lexTable[ch] & IS_WHITESPACE) != 0)) {
ch = Read(aErrorCode);
// special case: if trailing whitespace is CR/LF, eat both chars (not part of spec, but should be)
if (ch == '\r') {
ch = Peek(aErrorCode);
if (ch == '\n') {
ch = Read(aErrorCode);
}
}
}
}
return rv;
} else {
// "Any character except a hexidecimal digit can be escaped to
// remove its special meaning by putting a backslash in front"
// -- CSS1 spec section 7.1
if (EatNewline(aErrorCode)) { // skip escaped newline
ch = 0;
}
else {
(void) Read(aErrorCode);
}
return ch;
}
}
/**
* Gather up the characters in an identifier. The identfier was
* started by "aChar" which will be appended to aIdent. The result
* will be aIdent with all of the identifier characters appended
* until the first non-identifier character is seen. The termination
* character is unread for the future re-reading.
*/
PRBool nsCSSScanner::GatherIdent(PRInt32& aErrorCode, PRInt32 aChar,
nsString& aIdent)
{
if (aChar == CSS_ESCAPE) {
aChar = ParseEscape(aErrorCode);
}
if (0 < aChar) {
aIdent.Append(PRUnichar(aChar));
}
for (;;) {
aChar = Read(aErrorCode);
if (aChar < 0) break;
if (aChar == CSS_ESCAPE) {
aChar = ParseEscape(aErrorCode);
if (0 < aChar) {
aIdent.Append(PRUnichar(aChar));
}
} else if ((aChar <= 255) && ((gLexTable[aChar] & IS_IDENT) != 0)) {
aIdent.Append(PRUnichar(aChar));
} else {
Unread();
break;
}
}
return PR_TRUE;
}
PRBool nsCSSScanner::ParseID(PRInt32& aErrorCode,
PRInt32 aChar,
nsCSSToken& aToken)
{
aToken.mIdent.SetLength(0);
aToken.mType = eCSSToken_ID;
return GatherIdent(aErrorCode, 0, aToken.mIdent);
}
PRBool nsCSSScanner::ParseIdent(PRInt32& aErrorCode,
PRInt32 aChar,
nsCSSToken& aToken)
{
nsString& ident = aToken.mIdent;
ident.SetLength(0);
if (!GatherIdent(aErrorCode, aChar, ident)) {
return PR_FALSE;
}
nsCSSTokenType tokenType = eCSSToken_Ident;
// look for functions (ie: "ident(")
if (PRUnichar('(') == PRUnichar(Peek(aErrorCode))) { // this is a function definition
tokenType = eCSSToken_Function;
}
aToken.mType = tokenType;
return PR_TRUE;
}
PRBool nsCSSScanner::ParseAtKeyword(PRInt32& aErrorCode, PRInt32 aChar,
nsCSSToken& aToken)
{
aToken.mIdent.SetLength(0);
aToken.mType = eCSSToken_AtKeyword;
return GatherIdent(aErrorCode, 0, aToken.mIdent);
}
PRBool nsCSSScanner::ParseNumber(PRInt32& aErrorCode, PRInt32 c,
nsCSSToken& aToken)
{
nsString& ident = aToken.mIdent;
ident.SetLength(0);
PRBool gotDot = (c == '.') ? PR_TRUE : PR_FALSE;
if (c != '+') {
ident.Append(PRUnichar(c));
}
// Gather up characters that make up the number
PRUint8* lexTable = gLexTable;
for (;;) {
c = Read(aErrorCode);
if (c < 0) break;
if (!gotDot && (c == '.')) {
gotDot = PR_TRUE;
} else if ((c > 255) || ((lexTable[c] & IS_DIGIT) == 0)) {
break;
}
ident.Append(PRUnichar(c));
}
// Convert number to floating point
nsCSSTokenType type = eCSSToken_Number;
PRInt32 ec;
float value = ident.ToFloat(&ec);
// Look at character that terminated the number
aToken.mIntegerValid = PR_FALSE;
if (c >= 0) {
if ((c <= 255) && ((lexTable[c] & START_IDENT) != 0)) {
ident.SetLength(0);
if (!GatherIdent(aErrorCode, c, ident)) {
return PR_FALSE;
}
type = eCSSToken_Dimension;
} else if ('%' == c) {
type = eCSSToken_Percentage;
value = value / 100.0f;
ident.SetLength(0);
} else {
// Put back character that stopped numeric scan
Unread();
if (!gotDot) {
aToken.mInteger = ident.ToInteger(&ec);
aToken.mIntegerValid = PR_TRUE;
}
ident.SetLength(0);
}
}
else { // stream ended
if (!gotDot) {
aToken.mInteger = ident.ToInteger(&ec);
aToken.mIntegerValid = PR_TRUE;
}
ident.SetLength(0);
}
aToken.mNumber = value;
aToken.mType = type;
return PR_TRUE;
}
PRBool nsCSSScanner::ParseCComment(PRInt32& aErrorCode, nsCSSToken& aToken)
{
nsString& ident = aToken.mIdent;
for (;;) {
PRInt32 ch = Read(aErrorCode);
if (ch < 0) break;
if (ch == '*') {
if (LookAhead(aErrorCode, '/')) {
ident.Append(PRUnichar(ch));
ident.Append('/');
break;
}
}
#ifdef COLLECT_WHITESPACE
ident.Append(PRUnichar(ch));
#endif
}
aToken.mType = eCSSToken_WhiteSpace;
return PR_TRUE;
}
PRBool nsCSSScanner::ParseEOLComment(PRInt32& aErrorCode, nsCSSToken& aToken)
{
nsString& ident = aToken.mIdent;
ident.SetLength(0);
for (;;) {
if (EatNewline(aErrorCode)) {
break;
}
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
break;
}
#ifdef COLLECT_WHITESPACE
ident.Append(PRUnichar(ch));
#endif
}
aToken.mType = eCSSToken_WhiteSpace;
return PR_TRUE;
}
PRBool nsCSSScanner::GatherString(PRInt32& aErrorCode, PRInt32 aStop,
nsString& aBuffer)
{
for (;;) {
if (EatNewline(aErrorCode)) {
break;
}
PRInt32 ch = Read(aErrorCode);
if (ch < 0) {
return PR_FALSE;
}
if (ch == aStop) {
break;
}
if (ch == CSS_ESCAPE) {
ch = ParseEscape(aErrorCode);
if (ch < 0) {
return PR_FALSE;
}
}
if (0 < ch) {
aBuffer.Append(PRUnichar(ch));
}
}
return PR_TRUE;
}
PRBool nsCSSScanner::ParseString(PRInt32& aErrorCode, PRInt32 aStop,
nsCSSToken& aToken)
{
aToken.mIdent.SetLength(0);
aToken.mType = eCSSToken_String;
aToken.mSymbol = PRUnichar(aStop); // remember how it's quoted
return GatherString(aErrorCode, aStop, aToken.mIdent);
}
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