GOB: Add a way to reopen currently opened IMD/VMD videos

This is a workaround for how Lost in Time behaves in combination
with changes I made to the DataIO code for running Urban Runner
on low-memory devices.

Urban Runner's intro are far to big to have them copied into
memory for these devices, so I made the DataIO code return a
SafeSeekableSubReadStream into the opened archive stream instead.
Unfortunately, Lost in Time might not close a video file when it
closes the data file which it was originally in, especially when
loading a saved game. Since the video player needs to be able to
gaplessly continue a video and there does not, by itself, close
the video if not requested by the scripts, this leads to reading
out of an already closed stream in certain cases.

So, to worka round this issues, the video player tries to reopen
each currently opened video after a data archive was closed, to
make sure that that video is still available. If not, the video
is closed.

2 files changed, 54 insertions, 0 deletions

diff --git a/video/coktel_decoder.cpp b/video/coktel_decoder.cpp
index be36874db4..0c7ade1b8a 100644
--- a/video/coktel_decoder.cpp
+++ b/video/coktel_decoder.cpp
@@ -646,6 +646,21 @@ PreIMDDecoder::~PreIMDDecoder() {
 	close();
 }
 
+bool PreIMDDecoder::reloadStream(Common::SeekableReadStream *stream) {
+	if (!_stream)
+		return false;
+
+	if (!stream->seek(_stream->pos())) {
+		close();
+		return false;
+	}
+
+	delete _stream;
+	_stream = stream;
+
+	return true;
+}
+
 bool PreIMDDecoder::seek(int32 frame, int whence, bool restart) {
 	if (!evaluateSeekFrame(frame, whence))
 		return false;
@@ -840,6 +855,21 @@ IMDDecoder::~IMDDecoder() {
 	close();
 }
 
+bool IMDDecoder::reloadStream(Common::SeekableReadStream *stream) {
+	if (!_stream)
+		return false;
+
+	if (!stream->seek(_stream->pos())) {
+		close();
+		return false;
+	}
+
+	delete _stream;
+	_stream = stream;
+
+	return true;
+}
+
 bool IMDDecoder::seek(int32 frame, int whence, bool restart) {
 	if (!evaluateSeekFrame(frame, whence))
 		return false;
@@ -1536,6 +1566,21 @@ VMDDecoder::~VMDDecoder() {
 	close();
 }
 
+bool VMDDecoder::reloadStream(Common::SeekableReadStream *stream) {
+	if (!_stream)
+		return false;
+
+	if (!stream->seek(_stream->pos())) {
+		close();
+		return false;
+	}
+
+	delete _stream;
+	_stream = stream;
+
+	return true;
+}
+
 bool VMDDecoder::seek(int32 frame, int whence, bool restart) {
 	if (!evaluateSeekFrame(frame, whence))
 		return false;
diff --git a/video/coktel_decoder.h b/video/coktel_decoder.h
index 68696d5ff3..c88d982191 100644
--- a/video/coktel_decoder.h
+++ b/video/coktel_decoder.h
@@ -79,6 +79,9 @@ public:
 			Audio::Mixer::SoundType soundType = Audio::Mixer::kPlainSoundType);
 	~CoktelDecoder();
 
+	/** Replace the current video stream with this identical one. */
+	virtual bool reloadStream(Common::SeekableReadStream *stream) = 0;
+
 	virtual bool seek(int32 frame, int whence = SEEK_SET, bool restart = false) = 0;
 
 	/** Draw directly onto the specified video memory. */
@@ -237,6 +240,8 @@ public:
 			Audio::Mixer::SoundType soundType = Audio::Mixer::kPlainSoundType);
 	~PreIMDDecoder();
 
+	bool reloadStream(Common::SeekableReadStream *stream);
+
 	bool seek(int32 frame, int whence = SEEK_SET, bool restart = false);
 
 
@@ -268,6 +273,8 @@ public:
 	IMDDecoder(Audio::Mixer *mixer, Audio::Mixer::SoundType soundType = Audio::Mixer::kPlainSoundType);
 	~IMDDecoder();
 
+	bool reloadStream(Common::SeekableReadStream *stream);
+
 	bool seek(int32 frame, int whence = SEEK_SET, bool restart = false);
 
 	void setXY(uint16 x, uint16 y);
@@ -364,6 +371,8 @@ public:
 	VMDDecoder(Audio::Mixer *mixer, Audio::Mixer::SoundType soundType = Audio::Mixer::kPlainSoundType);
 	~VMDDecoder();
 
+	bool reloadStream(Common::SeekableReadStream *stream);
+
 	bool seek(int32 frame, int whence = SEEK_SET, bool restart = false);
 
 	void setXY(uint16 x, uint16 y);