michael@0: /*
michael@0:  * Copyright (C) 2011 Apple Inc. All rights reserved.
michael@0:  * Copyright (C) 2011 Mozilla Corporation. All rights reserved.
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 1. Redistributions of source code must retain the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer.
michael@0:  * 2. Redistributions in binary form must reproduce the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer in the
michael@0:  *    documentation and/or other materials provided with the distribution.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
michael@0:  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
michael@0:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
michael@0:  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
michael@0:  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
michael@0:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
michael@0:  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
michael@0:  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0:  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: #ifndef WEBGLVALIDATESTRINGS_H_
michael@0: #define WEBGLVALIDATESTRINGS_H_
michael@0: 
michael@0: #include "WebGLContext.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: // The following code was taken from the WebKit WebGL implementation,
michael@0: // which can be found here:
michael@0: // http://trac.webkit.org/browser/trunk/Source/WebCore/html/canvas/WebGLRenderingContext.cpp?rev=93625#L121
michael@0: // Note that some modifications were done to adapt it to Mozilla.
michael@0: /****** BEGIN CODE TAKEN FROM WEBKIT ******/
michael@0:     bool WebGLContext::ValidateGLSLCharacter(char16_t c)
michael@0:     {
michael@0:         // Printing characters are valid except " $ ` @ \ ' DEL.
michael@0:         if (c >= 32 && c <= 126 &&
michael@0:             c != '"' && c != '$' && c != '`' && c != '@' && c != '\\' && c != '\'')
michael@0:         {
michael@0:              return true;
michael@0:         }
michael@0: 
michael@0:         // Horizontal tab, line feed, vertical tab, form feed, carriage return are also valid.
michael@0:         if (c >= 9 && c <= 13) {
michael@0:              return true;
michael@0:         }
michael@0: 
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // Strips comments from shader text. This allows non-ASCII characters
michael@0:     // to be used in comments without potentially breaking OpenGL
michael@0:     // implementations not expecting characters outside the GLSL ES set.
michael@0:     class StripComments {
michael@0:     public:
michael@0:         StripComments(const nsAString& str)
michael@0:             : m_parseState(BeginningOfLine)
michael@0:             , m_end(str.EndReading())
michael@0:             , m_current(str.BeginReading())
michael@0:             , m_position(0)
michael@0:         {
michael@0:             m_result.SetLength(str.Length());
michael@0:             parse();
michael@0:         }
michael@0: 
michael@0:         const nsTArray<char16_t>& result()
michael@0:         {
michael@0:             return m_result;
michael@0:         }
michael@0: 
michael@0:         size_t length()
michael@0:         {
michael@0:             return m_position;
michael@0:         }
michael@0: 
michael@0:     private:
michael@0:         bool hasMoreCharacters()
michael@0:         {
michael@0:             return (m_current < m_end);
michael@0:         }
michael@0: 
michael@0:         void parse()
michael@0:         {
michael@0:             while (hasMoreCharacters()) {
michael@0:                 process(current());
michael@0:                 // process() might advance the position.
michael@0:                 if (hasMoreCharacters())
michael@0:                     advance();
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         void process(char16_t);
michael@0: 
michael@0:         bool peek(char16_t& character)
michael@0:         {
michael@0:             if (m_current + 1 >= m_end)
michael@0:                 return false;
michael@0:             character = *(m_current + 1);
michael@0:             return true;
michael@0:         }
michael@0: 
michael@0:         char16_t current()
michael@0:         {
michael@0:             //ASSERT(m_position < m_length);
michael@0:             return *m_current;
michael@0:         }
michael@0: 
michael@0:         void advance()
michael@0:         {
michael@0:             ++m_current;
michael@0:         }
michael@0: 
michael@0:         bool isNewline(char16_t character)
michael@0:         {
michael@0:             // Don't attempt to canonicalize newline related characters.
michael@0:             return (character == '\n' || character == '\r');
michael@0:         }
michael@0: 
michael@0:         void emit(char16_t character)
michael@0:         {
michael@0:             m_result[m_position++] = character;
michael@0:         }
michael@0: 
michael@0:         enum ParseState {
michael@0:             // Have not seen an ASCII non-whitespace character yet on
michael@0:             // this line. Possible that we might see a preprocessor
michael@0:             // directive.
michael@0:             BeginningOfLine,
michael@0: 
michael@0:             // Have seen at least one ASCII non-whitespace character
michael@0:             // on this line.
michael@0:             MiddleOfLine,
michael@0: 
michael@0:             // Handling a preprocessor directive. Passes through all
michael@0:             // characters up to the end of the line. Disables comment
michael@0:             // processing.
michael@0:             InPreprocessorDirective,
michael@0: 
michael@0:             // Handling a single-line comment. The comment text is
michael@0:             // replaced with a single space.
michael@0:             InSingleLineComment,
michael@0: 
michael@0:             // Handling a multi-line comment. Newlines are passed
michael@0:             // through to preserve line numbers.
michael@0:             InMultiLineComment
michael@0:         };
michael@0: 
michael@0:         ParseState m_parseState;
michael@0:         const char16_t* m_end;
michael@0:         const char16_t* m_current;
michael@0:         size_t m_position;
michael@0:         nsTArray<char16_t> m_result;
michael@0:     };
michael@0: 
michael@0:     void StripComments::process(char16_t c)
michael@0:     {
michael@0:         if (isNewline(c)) {
michael@0:             // No matter what state we are in, pass through newlines
michael@0:             // so we preserve line numbers.
michael@0:             emit(c);
michael@0: 
michael@0:             if (m_parseState != InMultiLineComment)
michael@0:                 m_parseState = BeginningOfLine;
michael@0: 
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         char16_t temp = 0;
michael@0:         switch (m_parseState) {
michael@0:         case BeginningOfLine:
michael@0:             // If it's an ASCII space.
michael@0:             if (c <= ' ' && (c == ' ' || (c <= 0xD && c >= 0x9))) {
michael@0:                 emit(c);
michael@0:                 break;
michael@0:             }
michael@0: 
michael@0:             if (c == '#') {
michael@0:                 m_parseState = InPreprocessorDirective;
michael@0:                 emit(c);
michael@0:                 break;
michael@0:             }
michael@0: 
michael@0:             // Transition to normal state and re-handle character.
michael@0:             m_parseState = MiddleOfLine;
michael@0:             process(c);
michael@0:             break;
michael@0: 
michael@0:         case MiddleOfLine:
michael@0:             if (c == '/' && peek(temp)) {
michael@0:                 if (temp == '/') {
michael@0:                     m_parseState = InSingleLineComment;
michael@0:                     emit(' ');
michael@0:                     advance();
michael@0:                     break;
michael@0:                 }
michael@0: 
michael@0:                 if (temp == '*') {
michael@0:                     m_parseState = InMultiLineComment;
michael@0:                     // Emit the comment start in case the user has
michael@0:                     // an unclosed comment and we want to later
michael@0:                     // signal an error.
michael@0:                     emit('/');
michael@0:                     emit('*');
michael@0:                     advance();
michael@0:                     break;
michael@0:                 }
michael@0:             }
michael@0: 
michael@0:             emit(c);
michael@0:             break;
michael@0: 
michael@0:         case InPreprocessorDirective:
michael@0:             // No matter what the character is, just pass it
michael@0:             // through. Do not parse comments in this state. This
michael@0:             // might not be the right thing to do long term, but it
michael@0:             // should handle the #error preprocessor directive.
michael@0:             emit(c);
michael@0:             break;
michael@0: 
michael@0:         case InSingleLineComment:
michael@0:             // The newline code at the top of this function takes care
michael@0:             // of resetting our state when we get out of the
michael@0:             // single-line comment. Swallow all other characters.
michael@0:             break;
michael@0: 
michael@0:         case InMultiLineComment:
michael@0:             if (c == '*' && peek(temp) && temp == '/') {
michael@0:                 emit('*');
michael@0:                 emit('/');
michael@0:                 m_parseState = MiddleOfLine;
michael@0:                 advance();
michael@0:                 break;
michael@0:             }
michael@0: 
michael@0:             // Swallow all other characters. Unclear whether we may
michael@0:             // want or need to just emit a space per character to try
michael@0:             // to preserve column numbers for debugging purposes.
michael@0:             break;
michael@0:         }
michael@0:     }
michael@0: 
michael@0: /****** END CODE TAKEN FROM WEBKIT ******/
michael@0: 
michael@0: } // end namespace mozilla
michael@0: 
michael@0: #endif // WEBGLVALIDATESTRINGS_H_