From 6992106dc7894fab3f620263e99b4083b36bf9e8 Mon Sep 17 00:00:00 2001
From: wolfbeast <mcwerewolf@wolfbeast.com>
Date: Thu, 7 Feb 2019 22:06:24 +0100
Subject: Use existing image decoders to handle clipboard BMP data.

This gets rid of the old nsImageClipboard widget code in favor of using
the nsBMPDecoder in imglib.
---
 image/DecoderFactory.cpp        |  7 +++++++
 image/DecoderFactory.h          |  1 +
 image/decoders/nsBMPDecoder.cpp | 17 ++++++++++++++---
 image/decoders/nsBMPDecoder.h   |  6 ++++--
 4 files changed, 26 insertions(+), 5 deletions(-)

(limited to 'image')

diff --git a/image/DecoderFactory.cpp b/image/DecoderFactory.cpp
index 2085fb7c4..dffe4dc21 100644
--- a/image/DecoderFactory.cpp
+++ b/image/DecoderFactory.cpp
@@ -58,6 +58,10 @@ DecoderFactory::GetDecoderType(const char* aMimeType)
   } else if (!strcmp(aMimeType, IMAGE_BMP_MS)) {
     type = DecoderType::BMP;
 
+  // BMP_CLIPBOARD
+  } else if (!strcmp(aMimeType, IMAGE_BMP_MS_CLIPBOARD)) {
+    type = DecoderType::BMP_CLIPBOARD;
+
   // ICO
   } else if (!strcmp(aMimeType, IMAGE_ICO)) {
     type = DecoderType::ICO;
@@ -100,6 +104,9 @@ DecoderFactory::GetDecoder(DecoderType aType,
     case DecoderType::BMP:
       decoder = new nsBMPDecoder(aImage);
       break;
+    case DecoderType::BMP_CLIPBOARD:
+      decoder = new nsBMPDecoder(aImage, /* aForClipboard */ true);
+      break;
     case DecoderType::ICO:
       decoder = new nsICODecoder(aImage);
       break;
diff --git a/image/DecoderFactory.h b/image/DecoderFactory.h
index f8cf64cc6..5638789ff 100644
--- a/image/DecoderFactory.h
+++ b/image/DecoderFactory.h
@@ -34,6 +34,7 @@ enum class DecoderType
   GIF,
   JPEG,
   BMP,
+  BMP_CLIPBOARD,
   ICO,
   ICON,
   WEBP,
diff --git a/image/decoders/nsBMPDecoder.cpp b/image/decoders/nsBMPDecoder.cpp
index 42bb3486a..fc79c223d 100644
--- a/image/decoders/nsBMPDecoder.cpp
+++ b/image/decoders/nsBMPDecoder.cpp
@@ -185,9 +185,11 @@ nsBMPDecoder::nsBMPDecoder(RasterImage* aImage, State aState, size_t aLength)
 {
 }
 
-// Constructor for normal BMP files.
-nsBMPDecoder::nsBMPDecoder(RasterImage* aImage)
-  : nsBMPDecoder(aImage, State::FILE_HEADER, FILE_HEADER_LENGTH)
+// Constructor for normal BMP files or from the clipboard.
+nsBMPDecoder::nsBMPDecoder(RasterImage* aImage, bool aForClipboard)
+  : nsBMPDecoder(aImage,
+                 aForClipboard ? State::CLIPBOARD_HEADER : State::FILE_HEADER,
+                 aForClipboard ? BIHSIZE_FIELD_LENGTH : FILE_HEADER_LENGTH)
 {
 }
 
@@ -455,6 +457,7 @@ nsBMPDecoder::DoDecode(SourceBufferIterator& aIterator, IResumable* aOnResume)
                     [=](State aState, const char* aData, size_t aLength) {
     switch (aState) {
       case State::FILE_HEADER:      return ReadFileHeader(aData, aLength);
+      case State::CLIPBOARD_HEADER: return ReadClipboardHeader(aData, aLength);
       case State::INFO_HEADER_SIZE: return ReadInfoHeaderSize(aData, aLength);
       case State::INFO_HEADER_REST: return ReadInfoHeaderRest(aData, aLength);
       case State::BITFIELDS:        return ReadBitfields(aData, aLength);
@@ -488,6 +491,14 @@ nsBMPDecoder::ReadFileHeader(const char* aData, size_t aLength)
   return Transition::To(State::INFO_HEADER_SIZE, BIHSIZE_FIELD_LENGTH);
 }
 
+LexerTransition<nsBMPDecoder::State>
+nsBMPDecoder::ReadClipboardHeader(const char* aData, size_t aLength)
+{
+  // With the clipboard, the data offset is the header length.
+  mH.mDataOffset = LittleEndian::readUint32(aData);
+  return ReadInfoHeaderSize(aData, aLength);
+}
+
 // We read the info header in two steps: (a) read the mBIHSize field to
 // determine how long the header is; (b) read the rest of the header.
 LexerTransition<nsBMPDecoder::State>
diff --git a/image/decoders/nsBMPDecoder.h b/image/decoders/nsBMPDecoder.h
index 0cf2af689..258381649 100644
--- a/image/decoders/nsBMPDecoder.h
+++ b/image/decoders/nsBMPDecoder.h
@@ -152,6 +152,7 @@ private:
 
   enum class State {
     FILE_HEADER,
+    CLIPBOARD_HEADER,
     INFO_HEADER_SIZE,
     INFO_HEADER_REST,
     BITFIELDS,
@@ -164,8 +165,8 @@ private:
     RLE_ABSOLUTE
   };
 
-  // This is the constructor used for normal BMP images.
-  explicit nsBMPDecoder(RasterImage* aImage);
+  // This is the constructor used for normal and clipboard BMP images.
+  explicit nsBMPDecoder(RasterImage* aImage, bool aForClipboard = false);
 
   // This is the constructor used for BMP resources in ICO images.
   nsBMPDecoder(RasterImage* aImage, uint32_t aDataOffset);
@@ -180,6 +181,7 @@ private:
   void FinishRow();
 
   LexerTransition<State> ReadFileHeader(const char* aData, size_t aLength);
+  LexerTransition<State> ReadClipboardHeader(const char* aData, size_t aLength);
   LexerTransition<State> ReadInfoHeaderSize(const char* aData, size_t aLength);
   LexerTransition<State> ReadInfoHeaderRest(const char* aData, size_t aLength);
   LexerTransition<State> ReadBitfields(const char* aData, size_t aLength);
-- 
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