tenfourfox/dom/canvas/WebGLValidateStrings.cpp

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2017-04-19 07:56:45 +00:00
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */
#include "WebGLValidateStrings.h"
#include "nsString.h"
#include "WebGLContext.h"
namespace mozilla {
// The following code was taken from the WebKit WebGL implementation,
// which can be found here:
// http://trac.webkit.org/browser/trunk/Source/WebCore/html/canvas/WebGLRenderingContext.cpp?rev=93625#L121
// Note that some modifications were done to adapt it to Mozilla.
/****** BEGIN CODE TAKEN FROM WEBKIT ******/
bool IsValidGLSLCharacter(char16_t c)
{
// Printing characters are valid except " $ ` @ \ ' DEL.
if (c >= 32 && c <= 126 &&
c != '"' && c != '$' && c != '`' && c != '@' && c != '\\' && c != '\'')
{
return true;
}
// Horizontal tab, line feed, vertical tab, form feed, carriage return
// are also valid.
if (c >= 9 && c <= 13) {
return true;
}
return false;
}
void StripComments::process(char16_t c)
{
if (isNewline(c)) {
// No matter what state we are in, pass through newlines
// so we preserve line numbers.
emit(c);
if (m_parseState != InMultiLineComment)
m_parseState = BeginningOfLine;
return;
}
char16_t temp = 0;
switch (m_parseState) {
case BeginningOfLine:
// If it's an ASCII space.
if (c <= ' ' && (c == ' ' || (c <= 0xD && c >= 0x9))) {
emit(c);
break;
}
if (c == '#') {
m_parseState = InPreprocessorDirective;
emit(c);
break;
}
// Transition to normal state and re-handle character.
m_parseState = MiddleOfLine;
process(c);
break;
case MiddleOfLine:
if (c == '/' && peek(temp)) {
if (temp == '/') {
m_parseState = InSingleLineComment;
emit(' ');
advance();
break;
}
if (temp == '*') {
m_parseState = InMultiLineComment;
// Emit the comment start in case the user has
// an unclosed comment and we want to later
// signal an error.
emit('/');
emit('*');
advance();
break;
}
}
emit(c);
break;
case InPreprocessorDirective:
// No matter what the character is, just pass it
// through. Do not parse comments in this state. This
// might not be the right thing to do long term, but it
// should handle the #error preprocessor directive.
emit(c);
break;
case InSingleLineComment:
// The newline code at the top of this function takes care
// of resetting our state when we get out of the
// single-line comment. Swallow all other characters.
break;
case InMultiLineComment:
if (c == '*' && peek(temp) && temp == '/') {
emit('*');
emit('/');
m_parseState = MiddleOfLine;
advance();
break;
}
// Swallow all other characters. Unclear whether we may
// want or need to just emit a space per character to try
// to preserve column numbers for debugging purposes.
break;
}
}
/****** END CODE TAKEN FROM WEBKIT ******/
bool
ValidateGLSLString(const nsAString& string, WebGLContext* webgl, const char* funcName)
{
for (size_t i = 0; i < string.Length(); ++i) {
if (!IsValidGLSLCharacter(string.CharAt(i))) {
webgl->ErrorInvalidValue("%s: String contains the illegal character '%d'",
funcName, string.CharAt(i));
return false;
}
}
return true;
}
bool
ValidateGLSLVariableName(const nsAString& name, WebGLContext* webgl, const char* funcName)
{
if (name.IsEmpty())
return false;
const uint32_t maxSize = 256;
if (name.Length() > maxSize) {
webgl->ErrorInvalidValue("%s: Identifier is %d characters long, exceeds the"
" maximum allowed length of %d characters.",
funcName, name.Length(), maxSize);
return false;
}
if (!ValidateGLSLString(name, webgl, funcName))
return false;
nsString prefix1 = NS_LITERAL_STRING("webgl_");
nsString prefix2 = NS_LITERAL_STRING("_webgl_");
if (Substring(name, 0, prefix1.Length()).Equals(prefix1) ||
Substring(name, 0, prefix2.Length()).Equals(prefix2))
{
webgl->ErrorInvalidOperation("%s: String contains a reserved GLSL prefix.",
funcName);
return false;
}
return true;
}
} // namespace mozilla