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image/decoders/nsPNGDecoder.h@ac0c01689b40 (annotated)

image/decoders/nsPNGDecoder.h

Thu, 15 Jan 2015 15:59:08 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Thu, 15 Jan 2015 15:59:08 +0100

branch

TOR_BUG_9701

changeset 10

ac0c01689b40

permissions

-rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0	2	*
michael@0	3	* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	4	* License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0	5	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	6
michael@0	7	#ifndef nsPNGDecoder_h__
michael@0	8	#define nsPNGDecoder_h__
michael@0	9
michael@0	10	#include "Decoder.h"
michael@0	11
michael@0	12	#include "gfxTypes.h"
michael@0	13
michael@0	14	#include "nsCOMPtr.h"
michael@0	15
michael@0	16	#include "png.h"
michael@0	17
michael@0	18	#include "qcms.h"
michael@0	19
michael@0	20	namespace mozilla {
michael@0	21	namespace image {
michael@0	22	class RasterImage;
michael@0	23
michael@0	24	class nsPNGDecoder : public Decoder
michael@0	25	{
michael@0	26	public:
michael@0	27	nsPNGDecoder(RasterImage &aImage);
michael@0	28	virtual ~nsPNGDecoder();
michael@0	29
michael@0	30	virtual void InitInternal();
michael@0	31	virtual void WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy aStrategy);
michael@0	32	virtual Telemetry::ID SpeedHistogram();
michael@0	33
michael@0	34	void CreateFrame(png_uint_32 x_offset, png_uint_32 y_offset,
michael@0	35	int32_t width, int32_t height,
michael@0	36	gfxImageFormat format);
michael@0	37	void EndImageFrame();
michael@0	38
michael@0	39	// Check if PNG is valid ICO (32bpp RGBA)
michael@0	40	// http://blogs.msdn.com/b/oldnewthing/archive/2010/10/22/10079192.aspx
michael@0	41	bool IsValidICO() const
michael@0	42	{
michael@0	43	// If there are errors in the call to png_get_IHDR, the error_callback in
michael@0	44	// nsPNGDecoder.cpp is called. In this error callback we do a longjmp, so
michael@0	45	// we need to save the jump buffer here. Oterwise we'll end up without a
michael@0	46	// proper callstack.
michael@0	47	if (setjmp(png_jmpbuf(mPNG))) {
michael@0	48	// We got here from a longjmp call indirectly from png_get_IHDR
michael@0	49	return false;
michael@0	50	}
michael@0	51
michael@0	52	png_uint_32
michael@0	53	png_width, // Unused
michael@0	54	png_height; // Unused
michael@0	55
michael@0	56	int png_bit_depth,
michael@0	57	png_color_type;
michael@0	58
michael@0	59	if (png_get_IHDR(mPNG, mInfo, &png_width, &png_height, &png_bit_depth,
michael@0	60	&png_color_type, nullptr, nullptr, nullptr)) {
michael@0	61
michael@0	62	return ((png_color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
michael@0	63	png_color_type == PNG_COLOR_TYPE_RGB) &&
michael@0	64	png_bit_depth == 8);
michael@0	65	} else {
michael@0	66	return false;
michael@0	67	}
michael@0	68	}
michael@0	69
michael@0	70	public:
michael@0	71	png_structp mPNG;
michael@0	72	png_infop mInfo;
michael@0	73	nsIntRect mFrameRect;
michael@0	74	uint8_t *mCMSLine;
michael@0	75	uint8_t *interlacebuf;
michael@0	76	qcms_profile *mInProfile;
michael@0	77	qcms_transform *mTransform;
michael@0	78
michael@0	79	gfxImageFormat format;
michael@0	80
michael@0	81	// For size decodes
michael@0	82	uint8_t mSizeBytes[8]; // Space for width and height, both 4 bytes
michael@0	83	uint32_t mHeaderBytesRead;
michael@0	84
michael@0	85	// whether CMS or premultiplied alpha are forced off
michael@0	86	uint32_t mCMSMode;
michael@0	87
michael@0	88	uint8_t mChannels;
michael@0	89	bool mFrameHasNoAlpha;
michael@0	90	bool mFrameIsHidden;
michael@0	91	bool mDisablePremultipliedAlpha;
michael@0	92
michael@0	93	struct AnimFrameInfo
michael@0	94	{
michael@0	95	AnimFrameInfo();
michael@0	96	#ifdef PNG_APNG_SUPPORTED
michael@0	97	AnimFrameInfo(png_structp aPNG, png_infop aInfo);
michael@0	98	#endif
michael@0	99
michael@0	100	FrameBlender::FrameDisposalMethod mDispose;
michael@0	101	FrameBlender::FrameBlendMethod mBlend;
michael@0	102	int32_t mTimeout;
michael@0	103	};
michael@0	104
michael@0	105	AnimFrameInfo mAnimInfo;
michael@0	106
michael@0	107	// The number of frames we've finished.
michael@0	108	uint32_t mNumFrames;
michael@0	109
michael@0	110	/*
michael@0	111	* libpng callbacks
michael@0	112	*
michael@0	113	* We put these in the class so that they can access protected members.
michael@0	114	*/
michael@0	115	static void PNGAPI info_callback(png_structp png_ptr, png_infop info_ptr);
michael@0	116	static void PNGAPI row_callback(png_structp png_ptr, png_bytep new_row,
michael@0	117	png_uint_32 row_num, int pass);
michael@0	118	#ifdef PNG_APNG_SUPPORTED
michael@0	119	static void PNGAPI frame_info_callback(png_structp png_ptr,
michael@0	120	png_uint_32 frame_num);
michael@0	121	#endif
michael@0	122	static void PNGAPI end_callback(png_structp png_ptr, png_infop info_ptr);
michael@0	123	static void PNGAPI error_callback(png_structp png_ptr,
michael@0	124	png_const_charp error_msg);
michael@0	125	static void PNGAPI warning_callback(png_structp png_ptr,
michael@0	126	png_const_charp warning_msg);
michael@0	127
michael@0	128	// This is defined in the PNG spec as an invariant. We use it to
michael@0	129	// do manual validation without libpng.
michael@0	130	static const uint8_t pngSignatureBytes[];
michael@0	131	};
michael@0	132
michael@0	133	} // namespace image
michael@0	134	} // namespace mozilla
michael@0	135
michael@0	136	#endif // nsPNGDecoder_h__