content/canvas/src/WebGLValidateStrings.h

   1 /*
   2  * Copyright (C) 2011 Apple Inc. All rights reserved.
   3  * Copyright (C) 2011 Mozilla Corporation. All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #ifndef WEBGLVALIDATESTRINGS_H_
  28 #define WEBGLVALIDATESTRINGS_H_
  29
  30 #include "WebGLContext.h"
  31
  32 namespace mozilla {
  33
  34 // The following code was taken from the WebKit WebGL implementation,
  35 // which can be found here:
  36 // http://trac.webkit.org/browser/trunk/Source/WebCore/html/canvas/WebGLRenderingContext.cpp?rev=93625#L121
  37 // Note that some modifications were done to adapt it to Mozilla.
  38 /****** BEGIN CODE TAKEN FROM WEBKIT ******/
  39     bool WebGLContext::ValidateGLSLCharacter(PRUnichar c)
  40     {
  41         // Printing characters are valid except " $ ` @ \ ' DEL.
  42         if (c >= 32 && c <= 126 &&
  43             c != '"' && c != '$' && c != '`' && c != '@' && c != '\\' && c != '\'')
  44         {
  45              return true;
  46         }
  47
  48         // Horizontal tab, line feed, vertical tab, form feed, carriage return are also valid.
  49         if (c >= 9 && c <= 13) {
  50              return true;
  51         }
  52
  53         return false;
  54     }
  55
  56     // Strips comments from shader text. This allows non-ASCII characters
  57     // to be used in comments without potentially breaking OpenGL
  58     // implementations not expecting characters outside the GLSL ES set.
  59     class StripComments {
  60     public:
  61         StripComments(const nsAString& str)
  62             : m_parseState(BeginningOfLine)
  63             , m_end(str.EndReading())
  64             , m_current(str.BeginReading())
  65             , m_position(0)
  66         {
  67             m_result.SetLength(str.Length());
  68             parse();
  69         }
  70
  71         const nsTArray<PRUnichar>& result()
  72         {
  73             return m_result;
  74         }
  75
  76         size_t length()
  77         {
  78             return m_position;
  79         }
  80
  81     private:
  82         bool hasMoreCharacters()
  83         {
  84             return (m_current < m_end);
  85         }
  86
  87         void parse()
  88         {
  89             while (hasMoreCharacters()) {
  90                 process(current());
  91                 // process() might advance the position.
  92                 if (hasMoreCharacters())
  93                     advance();
  94             }
  95         }
  96
  97         void process(PRUnichar);
  98
  99         bool peek(PRUnichar& character)
 100         {
 101             if (m_current + 1 >= m_end)
 102                 return false;
 103             character = *(m_current + 1);
 104             return true;
 105         }
 106
 107         PRUnichar current()
 108         {
 109             //ASSERT(m_position < m_length);
 110             return *m_current;
 111         }
 112
 113         void advance()
 114         {
 115             ++m_current;
 116         }
 117
 118         bool isNewline(PRUnichar character)
 119         {
 120             // Don't attempt to canonicalize newline related characters.
 121             return (character == '\n' || character == '\r');
 122         }
 123
 124         void emit(PRUnichar character)
 125         {
 126             m_result[m_position++] = character;
 127         }
 128
 129         enum ParseState {
 130             // Have not seen an ASCII non-whitespace character yet on
 131             // this line. Possible that we might see a preprocessor
 132             // directive.
 133             BeginningOfLine,
 134
 135             // Have seen at least one ASCII non-whitespace character
 136             // on this line.
 137             MiddleOfLine,
 138
 139             // Handling a preprocessor directive. Passes through all
 140             // characters up to the end of the line. Disables comment
 141             // processing.
 142             InPreprocessorDirective,
 143
 144             // Handling a single-line comment. The comment text is
 145             // replaced with a single space.
 146             InSingleLineComment,
 147
 148             // Handling a multi-line comment. Newlines are passed
 149             // through to preserve line numbers.
 150             InMultiLineComment
 151         };
 152
 153         ParseState m_parseState;
 154         const PRUnichar* m_end;
 155         const PRUnichar* m_current;
 156         size_t m_position;
 157         nsTArray<PRUnichar> m_result;
 158     };
 159
 160     void StripComments::process(PRUnichar c)
 161     {
 162         if (isNewline(c)) {
 163             // No matter what state we are in, pass through newlines
 164             // so we preserve line numbers.
 165             emit(c);
 166
 167             if (m_parseState != InMultiLineComment)
 168                 m_parseState = BeginningOfLine;
 169
 170             return;
 171         }
 172
 173         PRUnichar temp = 0;
 174         switch (m_parseState) {
 175         case BeginningOfLine:
 176             // If it's an ASCII space.
 177             if (c <= ' ' && (c == ' ' || (c <= 0xD && c >= 0x9))) {
 178                 emit(c);
 179                 break;
 180             }
 181
 182             if (c == '#') {
 183                 m_parseState = InPreprocessorDirective;
 184                 emit(c);
 185                 break;
 186             }
 187
 188             // Transition to normal state and re-handle character.
 189             m_parseState = MiddleOfLine;
 190             process(c);
 191             break;
 192
 193         case MiddleOfLine:
 194             if (c == '/' && peek(temp)) {
 195                 if (temp == '/') {
 196                     m_parseState = InSingleLineComment;
 197                     emit(' ');
 198                     advance();
 199                     break;
 200                 }
 201
 202                 if (temp == '*') {
 203                     m_parseState = InMultiLineComment;
 204                     // Emit the comment start in case the user has
 205                     // an unclosed comment and we want to later
 206                     // signal an error.
 207                     emit('/');
 208                     emit('*');
 209                     advance();
 210                     break;
 211                 }
 212             }
 213
 214             emit(c);
 215             break;
 216
 217         case InPreprocessorDirective:
 218             // No matter what the character is, just pass it
 219             // through. Do not parse comments in this state. This
 220             // might not be the right thing to do long term, but it
 221             // should handle the #error preprocessor directive.
 222             emit(c);
 223             break;
 224
 225         case InSingleLineComment:
 226             // The newline code at the top of this function takes care
 227             // of resetting our state when we get out of the
 228             // single-line comment. Swallow all other characters.
 229             break;
 230
 231         case InMultiLineComment:
 232             if (c == '*' && peek(temp) && temp == '/') {
 233                 emit('*');
 234                 emit('/');
 235                 m_parseState = MiddleOfLine;
 236                 advance();
 237                 break;
 238             }
 239
 240             // Swallow all other characters. Unclear whether we may
 241             // want or need to just emit a space per character to try
 242             // to preserve column numbers for debugging purposes.
 243             break;
 244         }
 245     }
 246
 247 /****** END CODE TAKEN FROM WEBKIT ******/
 248
 249 } // end namespace mozilla
 250
 251 #endif // WEBGLVALIDATESTRINGS_H_