The Tor Browser: gfx/src/nsColor.cpp@97036ab72558 (annotated)

gfx/src/nsColor.cpp@97036ab72558 (annotated)

gfx/src/nsColor.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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 "mozilla/ArrayUtils.h"         // for ArrayLength
 #include "mozilla/mozalloc.h"           // for operator delete, etc
 #include "nsColor.h"
 #include <sys/types.h>                  // for int32_t
 #include "nsColorNames.h"               // for nsColorNames
 #include "nsDebug.h"                    // for NS_ASSERTION, etc
 #include "nsStaticNameTable.h"
 #include "nsString.h"                   // for nsAutoCString, nsString, etc
 #include "nscore.h"                     // for nsAString, etc
 using namespace mozilla;
 // define an array of all color names
 #define GFX_COLOR(_name, _value) #_name,
 static const char* const kColorNames[] = {
 #include "nsColorNameList.h"
 };
 #undef GFX_COLOR
 // define an array of all color name values
 #define GFX_COLOR(_name, _value) _value,
 static const nscolor kColors[] = {
 #include "nsColorNameList.h"
 };
 #undef GFX_COLOR
 #define eColorName_COUNT (ArrayLength(kColorNames))
 #define eColorName_UNKNOWN (-1)
 static nsStaticCaseInsensitiveNameTable* gColorTable = nullptr;
 void nsColorNames::AddRefTable(void)
 {
   NS_ASSERTION(!gColorTable, "pre existing array!");
   if (!gColorTable) {
     gColorTable = new nsStaticCaseInsensitiveNameTable();
     if (gColorTable) {
 #ifdef DEBUG
     {
       // let's verify the table...
       for (uint32_t index = 0; index < eColorName_COUNT; ++index) {
         nsAutoCString temp1(kColorNames[index]);
         nsAutoCString temp2(kColorNames[index]);
         ToLowerCase(temp1);
         NS_ASSERTION(temp1.Equals(temp2), "upper case char in table");
       }
     }
 #endif
       gColorTable->Init(kColorNames, eColorName_COUNT);
     }
   }
 }
 void nsColorNames::ReleaseTable(void)
 {
   if (gColorTable) {
     delete gColorTable;
     gColorTable = nullptr;
   }
 }
 static int ComponentValue(const char16_t* aColorSpec, int aLen, int color, int dpc)
 {
   int component = 0;
   int index = (color * dpc);
   if (2 < dpc) {
     dpc = 2;
   }
   while (--dpc >= 0) {
     char16_t ch = ((index < aLen) ? aColorSpec[index++] : '0');
     if (('0' <= ch) && (ch <= '9')) {
       component = (component * 16) + (ch - '0');
     } else if ((('a' <= ch) && (ch <= 'f')) ||
                (('A' <= ch) && (ch <= 'F'))) {
       // "ch&7" handles lower and uppercase hex alphabetics
       component = (component * 16) + (ch & 7) + 9;
     }
     else {  // not a hex digit, treat it like 0
       component = (component * 16);
     }
   }
   return component;
 }
 NS_GFX_(bool) NS_HexToRGB(const nsAString& aColorSpec,
                                        nscolor* aResult)
 {
   const char16_t* buffer = aColorSpec.BeginReading();
   int nameLen = aColorSpec.Length();
   if ((nameLen == 3) || (nameLen == 6)) {
     // Make sure the digits are legal
     for (int i = 0; i < nameLen; i++) {
       char16_t ch = buffer[i];
       if (((ch >= '0') && (ch <= '9')) ||
           ((ch >= 'a') && (ch <= 'f')) ||
           ((ch >= 'A') && (ch <= 'F'))) {
         // Legal character
         continue;
       }
       // Whoops. Illegal character.
       return false;
     }
     // Convert the ascii to binary
     int dpc = ((3 == nameLen) ? 1 : 2);
     // Translate components from hex to binary
     int r = ComponentValue(buffer, nameLen, 0, dpc);
     int g = ComponentValue(buffer, nameLen, 1, dpc);
     int b = ComponentValue(buffer, nameLen, 2, dpc);
     if (dpc == 1) {
       // Scale single digit component to an 8 bit value. Replicate the
       // single digit to compute the new value.
       r = (r << 4) | r;
       g = (g << 4) | g;
       b = (b << 4) | b;
     }
     NS_ASSERTION((r >= 0) && (r <= 255), "bad r");
     NS_ASSERTION((g >= 0) && (g <= 255), "bad g");
     NS_ASSERTION((b >= 0) && (b <= 255), "bad b");
     *aResult = NS_RGB(r, g, b);
     return true;
   }
   // Improperly formatted color value
   return false;
 }
 // This implements part of the algorithm for legacy behavior described in
 // http://www.whatwg.org/specs/web-apps/current-work/complete/common-microsyntaxes.html#rules-for-parsing-a-legacy-color-value
 NS_GFX_(bool) NS_LooseHexToRGB(const nsString& aColorSpec, nscolor* aResult)
 {
   if (aColorSpec.EqualsLiteral("transparent")) {
     return false;
   }
   int nameLen = aColorSpec.Length();
   const char16_t* colorSpec = aColorSpec.get();
   if (nameLen > 128) {
     nameLen = 128;
   }
   if ('#' == colorSpec[0]) {
     ++colorSpec;
     --nameLen;
   }
   // digits per component
   int dpc = (nameLen + 2) / 3;
   int newdpc = dpc;
   // Use only the rightmost 8 characters of each component.
   if (newdpc > 8) {
     nameLen -= newdpc - 8;
     colorSpec += newdpc - 8;
     newdpc = 8;
   }
   // And then keep trimming characters at the left until we'd trim one
   // that would leave a nonzero value, but not past 2 characters per
   // component.
   while (newdpc > 2) {
     bool haveNonzero = false;
     for (int c = 0; c < 3; ++c) {
       NS_ABORT_IF_FALSE(c * dpc < nameLen,
                         "should not pass end of string while newdpc > 2");
       char16_t ch = colorSpec[c * dpc];
       if (('1' <= ch && ch <= '9') ||
           ('A' <= ch && ch <= 'F') ||
           ('a' <= ch && ch <= 'f')) {
         haveNonzero = true;
         break;
       }
     }
     if (haveNonzero) {
       break;
     }
     --newdpc;
     --nameLen;
     ++colorSpec;
   }
   // Translate components from hex to binary
   int r = ComponentValue(colorSpec, nameLen, 0, dpc);
   int g = ComponentValue(colorSpec, nameLen, 1, dpc);
   int b = ComponentValue(colorSpec, nameLen, 2, dpc);
   NS_ASSERTION((r >= 0) && (r <= 255), "bad r");
   NS_ASSERTION((g >= 0) && (g <= 255), "bad g");
   NS_ASSERTION((b >= 0) && (b <= 255), "bad b");
   *aResult = NS_RGB(r, g, b);
   return true;
 }
 NS_GFX_(bool) NS_ColorNameToRGB(const nsAString& aColorName, nscolor* aResult)
 {
   if (!gColorTable) return false;
   int32_t id = gColorTable->Lookup(aColorName);
   if (eColorName_UNKNOWN < id) {
     NS_ASSERTION(uint32_t(id) < eColorName_COUNT,
                  "gColorTable->Lookup messed up");
     if (aResult) {
       *aResult = kColors[id];
     }
     return true;
   }
   return false;
 }
 // Returns kColorNames, an array of all possible color names, and sets
 // *aSizeArray to the size of that array. Do NOT call free() on this array.
 NS_GFX_(const char * const *) NS_AllColorNames(size_t *aSizeArray)
 {
   *aSizeArray = ArrayLength(kColorNames);
   return kColorNames;
 }
 // Macro to blend two colors
 //
 // equivalent to target = (bg*(255-fgalpha) + fg*fgalpha)/255
 #define MOZ_BLEND(target, bg, fg, fgalpha)       \
   FAST_DIVIDE_BY_255(target, (bg)*(255-fgalpha) + (fg)*(fgalpha))
 NS_GFX_(nscolor)
 NS_ComposeColors(nscolor aBG, nscolor aFG)
 {
   // This function uses colors that are non premultiplied alpha.
   int r, g, b, a;
   int bgAlpha = NS_GET_A(aBG);
   int fgAlpha = NS_GET_A(aFG);
   // Compute the final alpha of the blended color
   // a = fgAlpha + bgAlpha*(255 - fgAlpha)/255;
   FAST_DIVIDE_BY_255(a, bgAlpha*(255-fgAlpha));
   a = fgAlpha + a;
   int blendAlpha;
   if (a == 0) {
     // In this case the blended color is totally trasparent,
     // we preserve the color information of the foreground color.
     blendAlpha = 255;
   } else {
     blendAlpha = (fgAlpha*255)/a;
   }
   MOZ_BLEND(r, NS_GET_R(aBG), NS_GET_R(aFG), blendAlpha);
   MOZ_BLEND(g, NS_GET_G(aBG), NS_GET_G(aFG), blendAlpha);
   MOZ_BLEND(b, NS_GET_B(aBG), NS_GET_B(aFG), blendAlpha);
   return NS_RGBA(r, g, b, a);
 }
 // Functions to convert from HSL color space to RGB color space.
 // This is the algorithm described in the CSS3 specification
 // helper
 static float
 HSL_HueToRGB(float m1, float m2, float h)
 {
   if (h < 0.0f)
     h += 1.0f;
   if (h > 1.0f)
     h -= 1.0f;
   if (h < (float)(1.0/6.0))
     return m1 + (m2 - m1)*h*6.0f;
   if (h < (float)(1.0/2.0))
     return m2;
   if (h < (float)(2.0/3.0))
     return m1 + (m2 - m1)*((float)(2.0/3.0) - h)*6.0f;
   return m1;
 }
 // The float parameters are all expected to be in the range 0-1
 NS_GFX_(nscolor)
 NS_HSL2RGB(float h, float s, float l)
 {
   uint8_t r, g, b;
   float m1, m2;
   if (l <= 0.5f) {
     m2 = l*(s+1);
   } else {
     m2 = l + s - l*s;
   }
   m1 = l*2 - m2;
   r = uint8_t(255 * HSL_HueToRGB(m1, m2, h + 1.0f/3.0f));
   g = uint8_t(255 * HSL_HueToRGB(m1, m2, h));
   b = uint8_t(255 * HSL_HueToRGB(m1, m2, h - 1.0f/3.0f));
   return NS_RGB(r, g, b);
 }
 NS_GFX_(const char*)
 NS_RGBToColorName(nscolor aColor)
 {
   for (size_t idx = 0; idx < ArrayLength(kColors); ++idx) {
     if (kColors[idx] == aColor) {
       return kColorNames[idx];
     }
   }
   return nullptr;
 }

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gfx/src/nsColor.cpp@97036ab72558 (annotated)

gfx/src/nsColor.cpp