ENGINES: Extend MetaEngine class with ExtendedSaves support

3 files changed, 289 insertions, 8 deletions

diff --git a/engines/metaengine.cpp b/engines/metaengine.cpp
new file mode 100644
index 0000000000..46a5f12619
--- /dev/null
+++ b/engines/metaengine.cpp
@@ -0,0 +1,226 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#include "engines/metaengine.h"
+
+#include "common/savefile.h"
+#include "common/system.h"
+
+#include "graphics/thumbnail.h"
+
+const char *MetaEngine::getSavegameFile(int saveGameIdx, const char *target) const {
+	static char buffer[100];
+
+	snprintf(buffer, 200, "%s.s%02d", target == nullptr ? getEngineId() : target, saveGameIdx);
+
+	return buffer;
+}
+
+const char *MetaEngine::getSavegamePattern(const char *target) const {
+	static char buffer[100];
+
+	snprintf(buffer, 200, "%s.s##", target == nullptr ? getEngineId() : target);
+
+	return buffer;
+}
+
+void MetaEngine::appendExtendedSave(Common::OutSaveFile *saveFile, uint32 playtime, Common::String desc) {
+	ExtendedSavegameHeader header;
+
+	uint headerPos = saveFile->pos();
+
+	strcpy(header.id, "SVMCR");
+	header.version = EXTENDED_SAVE_VERSION;
+
+	TimeDate curTime;
+	g_system->getTimeAndDate(curTime);
+
+	header.date = ((curTime.tm_mday & 0xFF) << 24) | (((curTime.tm_mon + 1) & 0xFF) << 16) | ((curTime.tm_year + 1900) & 0xFFFF);
+	header.time = ((curTime.tm_hour & 0xFF) << 8) | ((curTime.tm_min) & 0xFF);
+
+	saveFile->write(header.id, 6);
+	saveFile->writeByte(header.version);
+	saveFile->writeUint32LE(header.date);
+	saveFile->writeUint16LE(header.time);
+	saveFile->writeUint32LE(playtime);
+
+	saveFile->writeByte(desc.size());
+	saveFile->writeString(desc);
+
+	Graphics::saveThumbnail(*saveFile); // FIXME. Render proper screen
+
+	saveFile->writeUint32LE(headerPos);	// Store where the header starts
+
+	saveFile->finalize();
+}
+
+void MetaEngine::parseSavegameHeader(ExtendedSavegameHeader *header, SaveStateDescriptor *desc) {
+	int day = (header->date >> 24) & 0xFF;
+	int month = (header->date >> 16) & 0xFF;
+	int year = header->date & 0xFFFF;
+	desc->setSaveDate(year, month, day);
+	int hour = (header->time >> 8) & 0xFF;
+	int minutes = header->time & 0xFF;
+	desc->setSaveTime(hour, minutes);
+	desc->setPlayTime(header->playtime * 1000);
+
+	desc->setDescription(header->description);
+}
+
+void MetaEngine::fillDummyHeader(ExtendedSavegameHeader *header) {
+	// This is wrong header, perhaps it is original savegame. Thus fill out dummy values
+	header->date = (20 << 24) | (9 << 16) | 2016;
+	header->time = (9 << 8) | 56;
+	header->playtime = 0;
+}
+
+WARN_UNUSED_RESULT bool MetaEngine::readSavegameHeader(Common::InSaveFile *in, ExtendedSavegameHeader *header, bool skipThumbnail) {
+	uint oldPos = in->pos();
+
+	in->seek(-4, SEEK_END);
+
+	int headerOffset = in->readUint32LE();
+
+	// Sanity check
+	if (headerOffset >= in->pos() || headerOffset == 0) {
+		in->seek(oldPos, SEEK_SET); // Rewind the file
+		fillDummyHeader(header);
+		return false;
+	}
+
+	in->seek(headerOffset, SEEK_SET);
+
+	in->read(header->id, 6);
+
+	// Validate the header Id
+	if (strcmp(header->id, "SVMCR")) {
+		in->seek(oldPos, SEEK_SET); // Rewind the file
+		fillDummyHeader(header);
+		return false;
+	}
+
+	header->version = in->readByte();
+	header->date = in->readUint32LE();
+	header->time = in->readUint16LE();
+	header->playtime = in->readUint32LE();
+
+	if (header->version > 1)
+		header->description = in->readPascalString();
+
+	// Generate savename
+	SaveStateDescriptor desc;
+
+	parseSavegameHeader(header, &desc);
+
+	header->saveName = Common::String::format("%s %s", desc.getSaveDate().c_str(), desc.getSaveTime().c_str());
+
+	if (header->description.empty())
+		header->description = header->saveName;
+
+	// Get the thumbnail
+	if (!Graphics::loadThumbnail(*in, header->thumbnail, skipThumbnail)) {
+		in->seek(oldPos, SEEK_SET); // Rewind the file
+		return false;
+	}
+
+	in->seek(oldPos, SEEK_SET); // Rewind the file
+
+	return true;
+}
+
+
+///////////////////////////////////////
+// MetaEngine default implementations
+///////////////////////////////////////
+
+SaveStateList MetaEngine::listSaves(const char *target) const {
+	if (!hasFeature(kSavesUseExtendedFormat))
+		return SaveStateList();
+
+	Common::SaveFileManager *saveFileMan = g_system->getSavefileManager();
+	Common::StringArray filenames;
+	Common::String pattern(getSavegamePattern());
+
+	filenames = saveFileMan->listSavefiles(pattern);
+
+	SaveStateList saveList;
+	for (Common::StringArray::const_iterator file = filenames.begin(); file != filenames.end(); ++file) {
+		// Obtain the last 2 digits of the filename, since they correspond to the save slot
+		int slotNum = atoi(file->c_str() + file->size() - 2);
+
+		if (slotNum >= 0 && slotNum <= getMaximumSaveSlot()) {
+			Common::ScopedPtr<Common::InSaveFile> in(saveFileMan->openForLoading(*file));
+			if (in) {
+				ExtendedSavegameHeader header;
+				if (!readSavegameHeader(in.get(), &header)) {
+					continue;
+				}
+
+				SaveStateDescriptor desc;
+
+				parseSavegameHeader(&header, &desc);
+
+				desc.setSaveSlot(slotNum);
+
+				saveList.push_back(desc);
+			}
+		}
+	}
+
+	// Sort saves based on slot number.
+	Common::sort(saveList.begin(), saveList.end(), SaveStateDescriptorSlotComparator());
+	return saveList;
+}
+
+void MetaEngine::removeSaveState(const char *target, int slot) const {
+	if (!hasFeature(kSavesUseExtendedFormat))
+		return;
+
+	g_system->getSavefileManager()->removeSavefile(getSavegameFile(slot, target));
+}
+
+SaveStateDescriptor MetaEngine::querySaveMetaInfos(const char *target, int slot) const {
+	if (!hasFeature(kSavesUseExtendedFormat))
+		return SaveStateDescriptor();
+
+	Common::ScopedPtr<Common::InSaveFile> f(g_system->getSavefileManager()->openForLoading(
+		getSavegameFile(slot)));
+
+	if (f) {
+		ExtendedSavegameHeader header;
+		if (!readSavegameHeader(f.get(), &header, false)) {
+			return SaveStateDescriptor();
+		}
+
+		// Create the return descriptor
+		SaveStateDescriptor desc;
+
+		parseSavegameHeader(&header, &desc);
+
+		desc.setSaveSlot(slot);
+		desc.setThumbnail(header.thumbnail);
+
+		return desc;
+	}
+
+	return SaveStateDescriptor();
+}
diff --git a/engines/metaengine.h b/engines/metaengine.h
index 8853d65216..dfe882ad0a 100644
--- a/engines/metaengine.h
+++ b/engines/metaengine.h
@@ -37,7 +37,14 @@ class OSystem;
 
 namespace Common {
 class FSList;
+class OutSaveFile;
 class String;
+
+typedef SeekableReadStream InSaveFile;
+}
+
+namespace Graphics {
+struct Surface;
 }
 
 /**
@@ -53,6 +60,28 @@ struct ExtraGuiOption {
 
 typedef Common::Array<ExtraGuiOption> ExtraGuiOptions;
 
+#define EXTENDED_SAVE_VERSION 3
+
+struct ExtendedSavegameHeader {
+	char id[6];
+	uint8 version;
+	Common::String saveName;
+	Common::String description;
+	uint32 date;
+	uint16 time;
+	uint32 playtime;
+	Graphics::Surface *thumbnail;
+
+	ExtendedSavegameHeader() {
+		memset(id, 0, 6);
+		version = 0;
+		date = 0;
+		time = 0;
+		playtime = 0;
+		thumbnail = nullptr;
+	}
+};
+
 /**
  * A meta engine is essentially a factory for Engine instances with the
  * added ability of listing and detecting supported games.
@@ -114,9 +143,7 @@ public:
 	 * @param target	name of a config manager target
 	 * @return			a list of save state descriptors
 	 */
-	virtual SaveStateList listSaves(const char *target) const {
-		return SaveStateList();
-	}
+	virtual SaveStateList listSaves(const char *target) const;
 
 	/**
 	 * Return a list of extra GUI options for the specified target.
@@ -161,7 +188,7 @@ public:
 	 * @param target	name of a config manager target
 	 * @param slot		slot number of the save state to be removed
 	 */
-	virtual void removeSaveState(const char *target, int slot) const {}
+	virtual void removeSaveState(const char *target, int slot) const;
 
 	/**
 	 * Returns meta infos from the specified save state.
@@ -172,9 +199,22 @@ public:
 	 * @param target	name of a config manager target
 	 * @param slot		slot number of the save state
 	 */
-	virtual SaveStateDescriptor querySaveMetaInfos(const char *target, int slot) const {
-		return SaveStateDescriptor();
-	}
+	virtual SaveStateDescriptor querySaveMetaInfos(const char *target, int slot) const;
+
+	/**
+	 * Returns name of the save file for given slot and optional target.
+	 *
+	 * @param saveGameIdx	index of the save
+	 * @param target		game target. If omitted, then the engine id is used
+	 */
+	virtual const char *getSavegameFile(int saveGameIdx, const char *target = nullptr) const;
+
+	/**
+	 * Returns pattern for save files.
+	 *
+	 * @param target		game target. If omitted, then the engine id is used
+	 */
+	virtual const char *getSavegamePattern(const char *target = nullptr) const;
 
 	/** @name MetaEngineFeature flags */
 	//@{
@@ -251,7 +291,16 @@ public:
 		* unavailable. In that case Save/Load dialog for engine's
 		* games is locked during cloud saves sync.
 		*/
-		kSimpleSavesNames
+		kSimpleSavesNames,
+
+		/**
+		 * Uses default implementation of save header and thumbnail
+		 * appended to the save.
+		 * This flag requires the following flags to be set:
+		 *   kSavesSupportMetaInfo, kSavesSupportThumbnail, kSavesSupportCreationDate,
+		 *   kSavesSupportPlayTime
+		 */
+		kSavesUseExtendedFormat
 	};
 
 	/**
@@ -262,6 +311,11 @@ public:
 		return false;
 	}
 
+	static void appendExtendedSave(Common::OutSaveFile *saveFile, uint32 playtime, Common::String desc);
+	static void parseSavegameHeader(ExtendedSavegameHeader *header, SaveStateDescriptor *desc);
+	static void fillDummyHeader(ExtendedSavegameHeader *header);
+	static WARN_UNUSED_RESULT bool readSavegameHeader(Common::InSaveFile *in, ExtendedSavegameHeader *header, bool skipThumbnail = true);
+
 	//@}
 };
 
diff --git a/engines/module.mk b/engines/module.mk
index 7849c2ff25..e729d0beda 100644
--- a/engines/module.mk
+++ b/engines/module.mk
@@ -5,6 +5,7 @@ MODULE_OBJS := \
 	dialogs.o \
 	engine.o \
 	game.o \
+	metaengine.o \
 	obsolete.o \
 	savestate.o