layout/style/nsCSSScanner.h

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   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
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   8  * http://www.mozilla.org/MPL/
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  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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  15  * The Original Code is mozilla.org code.
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  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   L. David Baron <dbaron@dbaron.org>
  24  *   Daniel Glazman <glazman@netscape.com>
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  26  * Alternatively, the contents of this file may be used under the terms of
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  38  * ***** END LICENSE BLOCK ***** */
  39
  40 /* tokenization of CSS style sheets */
  41
  42 #ifndef nsCSSScanner_h___
  43 #define nsCSSScanner_h___
  44
  45 #include "nsString.h"
  46 #include "nsCOMPtr.h"
  47 class nsIUnicharInputStream;
  48
  49 // XXX turn this off for minimo builds
  50 #define CSS_REPORT_PARSE_ERRORS
  51
  52 #define CSS_BUFFER_SIZE 256
  53
  54 // for #ifdef CSS_REPORT_PARSE_ERRORS
  55 #include "nsXPIDLString.h"
  56 class nsIURI;
  57
  58 // Token types
  59 enum nsCSSTokenType {
  60   // A css identifier (e.g. foo)
  61   eCSSToken_Ident,          // mIdent
  62
  63   // A css at keyword (e.g. @foo)
  64   eCSSToken_AtKeyword,      // mIdent
  65
  66   // A css number without a percentage or dimension; with percentage;
  67   // without percentage but with a dimension
  68   eCSSToken_Number,         // mNumber
  69   eCSSToken_Percentage,     // mNumber
  70   eCSSToken_Dimension,      // mNumber + mIdent
  71
  72   // A css string (e.g. "foo" or 'foo')
  73   eCSSToken_String,         // mSymbol + mIdent + mSymbol
  74
  75   // Whitespace (e.g. " " or "/* abc */")
  76   eCSSToken_WhiteSpace,     // mIdent
  77
  78   // A css symbol (e.g. ':', ';', '+', etc.)
  79   eCSSToken_Symbol,         // mSymbol
  80
  81   // A css1 id (e.g. #foo3)
  82   eCSSToken_ID,             // mIdent
  83   // Just like eCSSToken_ID, except the part following the '#' is not
  84   // a valid CSS identifier (eg. starts with a digit, is the empty
  85   // string, etc).
  86   eCSSToken_Ref,            // mIdent
  87
  88   eCSSToken_Function,       // mIdent
  89
  90   eCSSToken_URL,            // mIdent
  91   eCSSToken_InvalidURL,     // doesn't matter
  92
  93   eCSSToken_HTMLComment,    // "<!--" or "-->"
  94
  95   eCSSToken_Includes,       // "~="
  96   eCSSToken_Dashmatch,      // "|="
  97   eCSSToken_Beginsmatch,    // "^="
  98   eCSSToken_Endsmatch,      // "$="
  99   eCSSToken_Containsmatch,  // "*="
 100
 101   // A special token indicating that there was an error in tokenization.
 102   // It's always an unterminated string.
 103   eCSSToken_Error           // mSymbol + mIdent
 104 };
 105
 106 struct nsCSSToken {
 107   nsCSSTokenType  mType;
 108   PRPackedBool    mIntegerValid; // for number and dimension
 109   PRPackedBool    mHasSign; // for number, percentage, and dimension
 110   nsAutoString    mIdent NS_OKONHEAP;
 111   float           mNumber;
 112   PRInt32         mInteger;
 113   PRUnichar       mSymbol;
 114
 115   nsCSSToken();
 116
 117   PRBool IsDimension() {
 118     return PRBool((eCSSToken_Dimension == mType) ||
 119                   ((eCSSToken_Number == mType) && (mNumber == 0.0f)));
 120   }
 121
 122   PRBool IsSymbol(PRUnichar aSymbol) {
 123     return PRBool((eCSSToken_Symbol == mType) && (mSymbol == aSymbol));
 124   }
 125
 126   void AppendToString(nsString& aBuffer);
 127 };
 128
 129 // CSS Scanner API. Used to tokenize an input stream using the CSS
 130 // forward compatible tokenization rules. This implementation is
 131 // private to this package and is only used internally by the css
 132 // parser.
 133 class nsCSSScanner {
 134   public:
 135   nsCSSScanner();
 136   ~nsCSSScanner();
 137
 138   // Init the scanner.
 139   // |aLineNumber == 1| is the beginning of a file, use |aLineNumber == 0|
 140   // when the line number is unknown.
 141   // Either aInput or (aBuffer and aCount) must be set.
 142   void Init(nsIUnicharInputStream* aInput,
 143             const PRUnichar *aBuffer, PRUint32 aCount,
 144             nsIURI* aURI, PRUint32 aLineNumber);
 145   void Close();
 146
 147   static PRBool InitGlobals();
 148   static void ReleaseGlobals();
 149
 150 #ifdef  MOZ_SVG
 151   // Set whether or not we are processing SVG
 152   void SetSVGMode(PRBool aSVGMode) {
 153     NS_ASSERTION(aSVGMode == PR_TRUE || aSVGMode == PR_FALSE,
 154                  "bad PRBool value");
 155     mSVGMode = aSVGMode;
 156   }
 157   PRBool IsSVGMode() const {
 158     return mSVGMode;
 159   }
 160
 161 #endif
 162 #ifdef CSS_REPORT_PARSE_ERRORS
 163   NS_HIDDEN_(void) AddToError(const nsSubstring& aErrorText);
 164   NS_HIDDEN_(void) OutputError();
 165   NS_HIDDEN_(void) ClearError();
 166
 167   // aMessage must take no parameters
 168   NS_HIDDEN_(void) ReportUnexpected(const char* aMessage);
 169   NS_HIDDEN_(void) ReportUnexpectedParams(const char* aMessage,
 170                                           const PRUnichar **aParams,
 171                                           PRUint32 aParamsLength);
 172   // aLookingFor is a plain string, not a format string
 173   NS_HIDDEN_(void) ReportUnexpectedEOF(const char* aLookingFor);
 174   // aLookingFor is a single character
 175   NS_HIDDEN_(void) ReportUnexpectedEOF(PRUnichar aLookingFor);
 176   // aMessage must take 1 parameter (for the string representation of the
 177   // unexpected token)
 178   NS_HIDDEN_(void) ReportUnexpectedToken(nsCSSToken& tok,
 179                                          const char *aMessage);
 180   // aParams's first entry must be null, and we'll fill in the token
 181   NS_HIDDEN_(void) ReportUnexpectedTokenParams(nsCSSToken& tok,
 182                                                const char* aMessage,
 183                                                const PRUnichar **aParams,
 184                                                PRUint32 aParamsLength);
 185 #endif
 186
 187   PRUint32 GetLineNumber() { return mLineNumber; }
 188
 189   // Get the next token. Return PR_FALSE on EOF. aTokenResult
 190   // is filled in with the data for the token.
 191   PRBool Next(nsCSSToken& aTokenResult);
 192
 193   // Get the next token that may be a string or unquoted URL or whitespace
 194   PRBool NextURL(nsCSSToken& aTokenResult);
 195
 196   // It's really ugly that we have to expose this, but it's the easiest
 197   // way to do :nth-child() parsing sanely.  (In particular, in
 198   // :nth-child(2n-1), "2n-1" is a dimension, and we need to push the
 199   // "-1" back so we can read it again as a number.)
 200   void Pushback(PRUnichar aChar);
 201
 202   // Reports operating-system level errors, e.g. read failures and
 203   // out of memory.
 204   nsresult GetLowLevelError();
 205
 206   // sometimes the parser wants to make note of a low-level error
 207   void SetLowLevelError(nsresult aErrorCode);
 208
 209 protected:
 210   PRBool EnsureData();
 211   PRInt32 Read();
 212   PRInt32 Peek();
 213   PRBool LookAhead(PRUnichar aChar);
 214   PRBool EatWhiteSpace();
 215   PRBool EatNewline();
 216
 217   void ParseAndAppendEscape(nsString& aOutput);
 218   PRBool ParseIdent(PRInt32 aChar, nsCSSToken& aResult);
 219   PRBool ParseAtKeyword(PRInt32 aChar, nsCSSToken& aResult);
 220   PRBool ParseNumber(PRInt32 aChar, nsCSSToken& aResult);
 221   PRBool ParseRef(PRInt32 aChar, nsCSSToken& aResult);
 222   PRBool ParseString(PRInt32 aChar, nsCSSToken& aResult);
 223 #if 0
 224   PRBool ParseCComment(nsCSSToken& aResult);
 225   PRBool ParseEOLComment(nsCSSToken& aResult);
 226 #endif
 227   PRBool SkipCComment();
 228
 229   PRBool GatherIdent(PRInt32 aChar, nsString& aIdent);
 230
 231   // Only used when input is a stream
 232   nsCOMPtr<nsIUnicharInputStream> mInputStream;
 233   PRUnichar mBuffer[CSS_BUFFER_SIZE];
 234
 235   const PRUnichar *mReadPointer;
 236   PRUint32 mOffset;
 237   PRUint32 mCount;
 238   PRUnichar* mPushback;
 239   PRInt32 mPushbackCount;
 240   PRInt32 mPushbackSize;
 241   PRUnichar mLocalPushback[4];
 242   nsresult mLowLevelError;
 243
 244   PRUint32 mLineNumber;
 245 #ifdef MOZ_SVG
 246   // True if we are in SVG mode; false in "normal" CSS
 247   PRPackedBool mSVGMode;
 248 #endif
 249 #ifdef CSS_REPORT_PARSE_ERRORS
 250   nsXPIDLCString mFileName;
 251   nsCOMPtr<nsIURI> mURI;  // Cached so we know to not refetch mFileName
 252   PRUint32 mErrorLineNumber, mColNumber, mErrorColNumber;
 253   nsFixedString mError;
 254   PRUnichar mErrorBuf[200];
 255 #endif
 256 };
 257
 258 #endif /* nsCSSScanner_h___ */