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 /* -*- 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 "nsJPEGEncoder.h"

 #include "prprf.h"

 #include "nsString.h"

 #include "nsStreamUtils.h"

 #include "gfxColor.h"

 #include <setjmp.h>

 #include "jerror.h"

 using namespace mozilla;

 NS_IMPL_ISUPPORTS(nsJPEGEncoder, imgIEncoder, nsIInputStream, nsIAsyncInputStream)

 // used to pass error info through the JPEG library

 struct encoder_error_mgr {

   jpeg_error_mgr pub;

   jmp_buf setjmp_buffer;

 };

 nsJPEGEncoder::nsJPEGEncoder() : mFinished(false),

                                  mImageBuffer(nullptr), mImageBufferSize(0),

                                  mImageBufferUsed(0), mImageBufferReadPoint(0),

                                  mCallback(nullptr),

                                  mCallbackTarget(nullptr), mNotifyThreshold(0),

                                  mReentrantMonitor("nsJPEGEncoder.mReentrantMonitor")

 {

 }

 nsJPEGEncoder::~nsJPEGEncoder()

 {

   if (mImageBuffer) {

     moz_free(mImageBuffer);

     mImageBuffer = nullptr;

   }

 }

 // nsJPEGEncoder::InitFromData

 //

 //    One output option is supported: "quality=X" where X is an integer in the

 //    range 0-100. Higher values for X give better quality.

 //

 //    Transparency is always discarded.

 NS_IMETHODIMP nsJPEGEncoder::InitFromData(const uint8_t* aData,

                                           uint32_t aLength, // (unused, req'd by JS)

                                           uint32_t aWidth,

                                           uint32_t aHeight,

                                           uint32_t aStride,

                                           uint32_t aInputFormat,

                                           const nsAString& aOutputOptions)

 {

   NS_ENSURE_ARG(aData);

   // validate input format

   if (aInputFormat != INPUT_FORMAT_RGB &&

       aInputFormat != INPUT_FORMAT_RGBA &&

       aInputFormat != INPUT_FORMAT_HOSTARGB)

     return NS_ERROR_INVALID_ARG;

   // Stride is the padded width of each row, so it better be longer (I'm afraid

   // people will not understand what stride means, so check it well)

   if ((aInputFormat == INPUT_FORMAT_RGB &&

        aStride < aWidth * 3) ||

       ((aInputFormat == INPUT_FORMAT_RGBA || aInputFormat == INPUT_FORMAT_HOSTARGB) &&

        aStride < aWidth * 4)) {

     NS_WARNING("Invalid stride for InitFromData");

     return NS_ERROR_INVALID_ARG;

   }

   // can't initialize more than once

   if (mImageBuffer != nullptr)

     return NS_ERROR_ALREADY_INITIALIZED;

   // options: we only have one option so this is easy

   int quality = 92;

   if (aOutputOptions.Length() > 0) {

     // have options string

     const nsString qualityPrefix(NS_LITERAL_STRING("quality="));

     if (aOutputOptions.Length() > qualityPrefix.Length()  &&

         StringBeginsWith(aOutputOptions, qualityPrefix)) {

       // have quality string

       nsCString value = NS_ConvertUTF16toUTF8(Substring(aOutputOptions,

                                                         qualityPrefix.Length()));

       int newquality = -1;

       if (PR_sscanf(value.get(), "%d", &newquality) == 1) {

         if (newquality >= 0 && newquality <= 100) {

           quality = newquality;

         } else {

           NS_WARNING("Quality value out of range, should be 0-100, using default");

         }

       } else {

         NS_WARNING("Quality value invalid, should be integer 0-100, using default");

       }

     }

     else {

       return NS_ERROR_INVALID_ARG;

     }

   }

   jpeg_compress_struct cinfo;

   // We set up the normal JPEG error routines, then override error_exit.

   // This must be done before the call to create_compress

   encoder_error_mgr errmgr;

   cinfo.err = jpeg_std_error(&errmgr.pub);

   errmgr.pub.error_exit = errorExit;

   // Establish the setjmp return context for my_error_exit to use.

   if (setjmp(errmgr.setjmp_buffer)) {

     // If we get here, the JPEG code has signaled an error.

     // We need to clean up the JPEG object, close the input file, and return.

     return NS_ERROR_FAILURE;

   }

   jpeg_create_compress(&cinfo);

   cinfo.image_width = aWidth;

   cinfo.image_height = aHeight;

   cinfo.input_components = 3;

   cinfo.in_color_space = JCS_RGB;

   cinfo.data_precision = 8;

   jpeg_set_defaults(&cinfo);

   jpeg_set_quality(&cinfo, quality, 1); // quality here is 0-100

   if (quality >= 90) {

     int i;

     for (i=0; i < MAX_COMPONENTS; i++) {

       cinfo.comp_info[i].h_samp_factor=1;

       cinfo.comp_info[i].v_samp_factor=1;

     }

   }

   // set up the destination manager

   jpeg_destination_mgr destmgr;

   destmgr.init_destination = initDestination;

   destmgr.empty_output_buffer = emptyOutputBuffer;

   destmgr.term_destination = termDestination;

   cinfo.dest = &destmgr;

   cinfo.client_data = this;

   jpeg_start_compress(&cinfo, 1);

   // feed it the rows

   if (aInputFormat == INPUT_FORMAT_RGB) {

     while (cinfo.next_scanline < cinfo.image_height) {

       const uint8_t* row = &aData[cinfo.next_scanline * aStride];

       jpeg_write_scanlines(&cinfo, const_cast<uint8_t**>(&row), 1);

     }

   } else if (aInputFormat == INPUT_FORMAT_RGBA) {

     uint8_t* row = new uint8_t[aWidth * 3];

     while (cinfo.next_scanline < cinfo.image_height) {

       ConvertRGBARow(&aData[cinfo.next_scanline * aStride], row, aWidth);

       jpeg_write_scanlines(&cinfo, &row, 1);

     }

     delete[] row;

   } else if (aInputFormat == INPUT_FORMAT_HOSTARGB) {

     uint8_t* row = new uint8_t[aWidth * 3];

     while (cinfo.next_scanline < cinfo.image_height) {

       ConvertHostARGBRow(&aData[cinfo.next_scanline * aStride], row, aWidth);

       jpeg_write_scanlines(&cinfo, &row, 1);

     }

     delete[] row;

   }

   jpeg_finish_compress(&cinfo);

   jpeg_destroy_compress(&cinfo);

   mFinished = true;

   NotifyListener();

   // if output callback can't get enough memory, it will free our buffer

   if (!mImageBuffer)

     return NS_ERROR_OUT_OF_MEMORY;

   return NS_OK;

 }

 NS_IMETHODIMP nsJPEGEncoder::StartImageEncode(uint32_t aWidth,

                                               uint32_t aHeight,

                                               uint32_t aInputFormat,

                                               const nsAString& aOutputOptions)

 {

   return NS_ERROR_NOT_IMPLEMENTED;

 }

 // Returns the number of bytes in the image buffer used.

 NS_IMETHODIMP nsJPEGEncoder::GetImageBufferUsed(uint32_t *aOutputSize)

 {

   NS_ENSURE_ARG_POINTER(aOutputSize);

   *aOutputSize = mImageBufferUsed;

   return NS_OK;

 }

 // Returns a pointer to the start of the image buffer

 NS_IMETHODIMP nsJPEGEncoder::GetImageBuffer(char **aOutputBuffer)

 {

   NS_ENSURE_ARG_POINTER(aOutputBuffer);

   *aOutputBuffer = reinterpret_cast<char*>(mImageBuffer);

   return NS_OK;

 }

 NS_IMETHODIMP nsJPEGEncoder::AddImageFrame(const uint8_t* aData,

                                            uint32_t aLength,

                                            uint32_t aWidth,

                                            uint32_t aHeight,

                                            uint32_t aStride,

                                            uint32_t aFrameFormat,

                                            const nsAString& aFrameOptions)

 {

   return NS_ERROR_NOT_IMPLEMENTED;

 }

 NS_IMETHODIMP nsJPEGEncoder::EndImageEncode()

 {

   return NS_ERROR_NOT_IMPLEMENTED;

 }

 /* void close (); */

 NS_IMETHODIMP nsJPEGEncoder::Close()

 {

   if (mImageBuffer != nullptr) {

     moz_free(mImageBuffer);

     mImageBuffer = nullptr;

     mImageBufferSize = 0;

     mImageBufferUsed = 0;

     mImageBufferReadPoint = 0;

   }

   return NS_OK;

 }

 /* unsigned long available (); */

 NS_IMETHODIMP nsJPEGEncoder::Available(uint64_t *_retval)

 {

   if (!mImageBuffer)

     return NS_BASE_STREAM_CLOSED;

   *_retval = mImageBufferUsed - mImageBufferReadPoint;

   return NS_OK;

 }

 /* [noscript] unsigned long read (in charPtr aBuf, in unsigned long aCount); */

 NS_IMETHODIMP nsJPEGEncoder::Read(char * aBuf, uint32_t aCount,

                                   uint32_t *_retval)

 {

   return ReadSegments(NS_CopySegmentToBuffer, aBuf, aCount, _retval);

 }

 /* [noscript] unsigned long readSegments (in nsWriteSegmentFun aWriter, in voidPtr aClosure, in unsigned long aCount); */

 NS_IMETHODIMP nsJPEGEncoder::ReadSegments(nsWriteSegmentFun aWriter, void *aClosure, uint32_t aCount, uint32_t *_retval)

 {

   // Avoid another thread reallocing the buffer underneath us

   ReentrantMonitorAutoEnter autoEnter(mReentrantMonitor);

   uint32_t maxCount = mImageBufferUsed - mImageBufferReadPoint;

   if (maxCount == 0) {

     *_retval = 0;

     return mFinished ? NS_OK : NS_BASE_STREAM_WOULD_BLOCK;

   }

   if (aCount > maxCount)

     aCount = maxCount;

   nsresult rv = aWriter(this, aClosure,

                         reinterpret_cast<const char*>(mImageBuffer+mImageBufferReadPoint),

                         0, aCount, _retval);

   if (NS_SUCCEEDED(rv)) {

     NS_ASSERTION(*_retval <= aCount, "bad write count");

     mImageBufferReadPoint += *_retval;

   }

   // errors returned from the writer end here!

   return NS_OK;

 }

 /* boolean isNonBlocking (); */

 NS_IMETHODIMP nsJPEGEncoder::IsNonBlocking(bool *_retval)

 {

   *_retval = true;

   return NS_OK;

 }

 NS_IMETHODIMP nsJPEGEncoder::AsyncWait(nsIInputStreamCallback *aCallback,

                                        uint32_t aFlags,

                                        uint32_t aRequestedCount,

                                        nsIEventTarget *aTarget)

 {

   if (aFlags != 0)

     return NS_ERROR_NOT_IMPLEMENTED;

   if (mCallback || mCallbackTarget)

     return NS_ERROR_UNEXPECTED;

   mCallbackTarget = aTarget;

   // 0 means "any number of bytes except 0"

   mNotifyThreshold = aRequestedCount;

   if (!aRequestedCount)

     mNotifyThreshold = 1024; // 1 KB seems good.  We don't want to notify incessantly

   // We set the callback absolutely last, because NotifyListener uses it to

   // determine if someone needs to be notified.  If we don't set it last,

   // NotifyListener might try to fire off a notification to a null target

   // which will generally cause non-threadsafe objects to be used off the main thread

   mCallback = aCallback;

   // What we are being asked for may be present already

   NotifyListener();

   return NS_OK;

 }

 NS_IMETHODIMP nsJPEGEncoder::CloseWithStatus(nsresult aStatus)

 {

   return Close();

 }

 // nsJPEGEncoder::ConvertHostARGBRow

 //

 //    Our colors are stored with premultiplied alphas, but we need

 //    an output with no alpha in machine-independent byte order.

 //

 //    See gfx/cairo/cairo/src/cairo-png.c

 void

 nsJPEGEncoder::ConvertHostARGBRow(const uint8_t* aSrc, uint8_t* aDest,

                                   uint32_t aPixelWidth)

 {

   for (uint32_t x = 0; x < aPixelWidth; x++) {

     const uint32_t& pixelIn = ((const uint32_t*)(aSrc))[x];

     uint8_t *pixelOut = &aDest[x * 3];

     pixelOut[0] = (pixelIn & 0xff0000) >> 16;

     pixelOut[1] = (pixelIn & 0x00ff00) >>  8;

     pixelOut[2] = (pixelIn & 0x0000ff) >>  0;

   }

 }

 /**

  * nsJPEGEncoder::ConvertRGBARow

  *

  * Input is RGBA, output is RGB, so we should alpha-premultiply.

  */

 void

 nsJPEGEncoder::ConvertRGBARow(const uint8_t* aSrc, uint8_t* aDest,

                               uint32_t aPixelWidth)

 {

   for (uint32_t x = 0; x < aPixelWidth; x++) {

     const uint8_t* pixelIn = &aSrc[x * 4];

     uint8_t* pixelOut = &aDest[x * 3];

     uint8_t alpha = pixelIn[3];

     pixelOut[0] = gfxPreMultiply(pixelIn[0], alpha);

     pixelOut[1] = gfxPreMultiply(pixelIn[1], alpha);

     pixelOut[2] = gfxPreMultiply(pixelIn[2], alpha);

   }

 }

 // nsJPEGEncoder::initDestination

 //

 //    Initialize destination. This is called by jpeg_start_compress() before

 //    any data is actually written. It must initialize next_output_byte and

 //    free_in_buffer. free_in_buffer must be initialized to a positive value.

 void // static

 nsJPEGEncoder::initDestination(jpeg_compress_struct* cinfo)

 {

   nsJPEGEncoder* that = static_cast<nsJPEGEncoder*>(cinfo->client_data);

   NS_ASSERTION(! that->mImageBuffer, "Image buffer already initialized");

   that->mImageBufferSize = 8192;

   that->mImageBuffer = (uint8_t*)moz_malloc(that->mImageBufferSize);

   that->mImageBufferUsed = 0;

   cinfo->dest->next_output_byte = that->mImageBuffer;

   cinfo->dest->free_in_buffer = that->mImageBufferSize;

 }

 // nsJPEGEncoder::emptyOutputBuffer

 //

 //    This is called whenever the buffer has filled (free_in_buffer reaches

 //    zero).  In typical applications, it should write out the *entire* buffer

 //    (use the saved start address and buffer length; ignore the current state

 //    of next_output_byte and free_in_buffer).  Then reset the pointer & count

 //    to the start of the buffer, and return TRUE indicating that the buffer

 //    has been dumped.  free_in_buffer must be set to a positive value when

 //    TRUE is returned.  A FALSE return should only be used when I/O suspension

 //    is desired (this operating mode is discussed in the next section).

 boolean // static

 nsJPEGEncoder::emptyOutputBuffer(jpeg_compress_struct* cinfo)

 {

   nsJPEGEncoder* that = static_cast<nsJPEGEncoder*>(cinfo->client_data);

   NS_ASSERTION(that->mImageBuffer, "No buffer to empty!");

   // When we're reallocing the buffer we need to take the lock to ensure

   // that nobody is trying to read from the buffer we are destroying

   ReentrantMonitorAutoEnter autoEnter(that->mReentrantMonitor);

   that->mImageBufferUsed = that->mImageBufferSize;

   // expand buffer, just double size each time

   that->mImageBufferSize *= 2;

   uint8_t* newBuf = (uint8_t*)moz_realloc(that->mImageBuffer,

                                           that->mImageBufferSize);

   if (! newBuf) {

     // can't resize, just zero (this will keep us from writing more)

     moz_free(that->mImageBuffer);

     that->mImageBuffer = nullptr;

     that->mImageBufferSize = 0;

     that->mImageBufferUsed = 0;

     // This seems to be the only way to do errors through the JPEG library.  We

     // pass an nsresult masquerading as an int, which works because the

     // setjmp() caller casts it back.

     longjmp(((encoder_error_mgr*)(cinfo->err))->setjmp_buffer,

             static_cast<int>(NS_ERROR_OUT_OF_MEMORY));

   }

   that->mImageBuffer = newBuf;

   cinfo->dest->next_output_byte = &that->mImageBuffer[that->mImageBufferUsed];

   cinfo->dest->free_in_buffer = that->mImageBufferSize - that->mImageBufferUsed;

   return 1;

 }

 // nsJPEGEncoder::termDestination

 //

 //    Terminate destination --- called by jpeg_finish_compress() after all data

 //    has been written.  In most applications, this must flush any data

 //    remaining in the buffer.  Use either next_output_byte or free_in_buffer

 //    to determine how much data is in the buffer.

 void // static

 nsJPEGEncoder::termDestination(jpeg_compress_struct* cinfo)

 {

   nsJPEGEncoder* that = static_cast<nsJPEGEncoder*>(cinfo->client_data);

   if (! that->mImageBuffer)

     return;

   that->mImageBufferUsed = cinfo->dest->next_output_byte - that->mImageBuffer;

   NS_ASSERTION(that->mImageBufferUsed < that->mImageBufferSize,

                "JPEG library busted, got a bad image buffer size");

   that->NotifyListener();

 }

 // nsJPEGEncoder::errorExit

 //

 //    Override the standard error method in the IJG JPEG decoder code. This

 //    was mostly copied from nsJPEGDecoder.cpp

 void // static

 nsJPEGEncoder::errorExit(jpeg_common_struct* cinfo)

 {

   nsresult error_code;

   encoder_error_mgr *err = (encoder_error_mgr *) cinfo->err;

   // Convert error to a browser error code

   switch (cinfo->err->msg_code) {

     case JERR_OUT_OF_MEMORY:

       error_code = NS_ERROR_OUT_OF_MEMORY;

       break;

     default:

       error_code = NS_ERROR_FAILURE;

   }

   // Return control to the setjmp point.  We pass an nsresult masquerading as

   // an int, which works because the setjmp() caller casts it back.

   longjmp(err->setjmp_buffer, static_cast<int>(error_code));

 }

 void

 nsJPEGEncoder::NotifyListener()

 {

   // We might call this function on multiple threads (any threads that call

   // AsyncWait and any that do encoding) so we lock to avoid notifying the

   // listener twice about the same data (which generally leads to a truncated

   // image).

   ReentrantMonitorAutoEnter autoEnter(mReentrantMonitor);

   if (mCallback &&

       (mImageBufferUsed - mImageBufferReadPoint >= mNotifyThreshold ||

        mFinished)) {

     nsCOMPtr<nsIInputStreamCallback> callback;

     if (mCallbackTarget) {

       callback = NS_NewInputStreamReadyEvent(mCallback, mCallbackTarget);

     } else {

       callback = mCallback;

     }

     NS_ASSERTION(callback, "Shouldn't fail to make the callback");

     // Null the callback first because OnInputStreamReady could reenter

     // AsyncWait

     mCallback = nullptr;

     mCallbackTarget = nullptr;

     mNotifyThreshold = 0;

     callback->OnInputStreamReady(this);

   }

 }