POSIX: Set the default screenshots path to the XDG Pictures directory

README

@@ -2896,6 +2896,8 @@ The default location, when no screenshot path is defined in the config file,
 depends on the OS:
   Windows: In Users\username\My Pictures\ScummVM Screenshots.
   macOS X: On the Desktop.
+  Other unices: In the XDG Pictures user directory,
+                 e.g. ~/Pictures/ScummVM Screenshots.
   Any other OS: In the current directory.
 
 

backends/platform/sdl/posix/posix.cpp

@@ -156,6 +156,101 @@ Common::String OSystem_POSIX::getDefaultConfigFileName() {
 	return configFile;
 }
 
+Common::String OSystem_POSIX::getXdgUserDir(const char *name) {
+	// The xdg-user-dirs configuration path is stored in the XDG config
+	// home directory. We start by retrieving this value.
+	Common::String configHome = getenv("XDG_CONFIG_HOME");
+	if (configHome.empty()) {
+		const char *home = getenv("HOME");
+		if (!home) {
+			return "";
+		}
+
+		configHome = Common::String::format("%s/.config", home);
+	}
+
+	// Find the requested directory line in the xdg-user-dirs configuration file
+	//   Example line value: XDG_PICTURES_DIR="$HOME/Pictures"
+	Common::FSNode userDirsFile(configHome + "/user-dirs.dirs");
+	if (!userDirsFile.exists() || !userDirsFile.isReadable() || userDirsFile.isDirectory()) {
+		return "";
+	}
+
+	Common::SeekableReadStream *userDirsStream = userDirsFile.createReadStream();
+	if (!userDirsStream) {
+		return "";
+	}
+
+	Common::String dirLinePrefix = Common::String::format("XDG_%s_DIR=", name);
+
+	Common::String directoryValue;
+	while (!userDirsStream->eos() && !userDirsStream->err()) {
+		Common::String userDirsLine = userDirsStream->readLine();
+		userDirsLine.trim();
+
+		if (userDirsLine.hasPrefix(dirLinePrefix)) {
+			directoryValue = Common::String(userDirsLine.c_str() + dirLinePrefix.size());
+			break;
+		}
+	}
+
+	delete userDirsStream;
+
+	// Extract the path from the value
+	//   Example value: "$HOME/Pictures"
+	if (directoryValue.empty() || directoryValue[0] != '"') {
+		return "";
+	}
+
+	if (directoryValue[directoryValue.size() - 1] != '"') {
+		return "";
+	}
+
+	// According to the spec the value is shell-escaped, and would need to be
+	// unescaped to be used, but neither the GTK+ nor the Qt implementation seem to
+	// properly perform that step, it's probably fine if we don't do it either.
+	Common::String directoryPath(directoryValue.c_str() + 1, directoryValue.size() - 2);
+
+	if (directoryPath.hasPrefix("$HOME/")) {
+		const char *home = getenv("HOME");
+		directoryPath = Common::String::format("%s%s", home, directoryPath.c_str() + 5);
+	}
+
+	// At this point, the path must be absolute
+	if (directoryPath.empty() || directoryPath[0] != '/') {
+		return "";
+	}
+
+	return directoryPath;
+}
+
+Common::String OSystem_POSIX::getScreenshotsPath() {
+	// If the user has configured a screenshots path, use it
+	const Common::String path = OSystem_SDL::getScreenshotsPath();
+	if (!path.empty()) {
+		return path;
+	}
+
+	// Otherwise, the default screenshots path is the "ScummVM Screenshots"
+	// directory in the XDG "Pictures" user directory, as defined in the
+	// xdg-user-dirs spec: https://www.freedesktop.org/wiki/Software/xdg-user-dirs/
+	Common::String picturesPath = getXdgUserDir("PICTURES");
+	if (picturesPath.empty()) {
+		return "";
+	}
+
+	if (!picturesPath.hasSuffix("/")) {
+		picturesPath += "/";
+	}
+
+	static const char *SCREENSHOTS_DIR_NAME = "ScummVM Screenshots";
+	if (!Posix::assureDirectoryExists(SCREENSHOTS_DIR_NAME, picturesPath.c_str())) {
+		return "";
+	}
+
+	return picturesPath + SCREENSHOTS_DIR_NAME + "/";
+}
+
 void OSystem_POSIX::addSysArchivesToSearchSet(Common::SearchSet &s, int priority) {
 #ifdef DATA_PATH
 	const char *snap = getenv("SNAP");

backends/platform/sdl/posix/posix.h

@@ -42,6 +42,8 @@ public:
 
 	virtual void addSysArchivesToSearchSet(Common::SearchSet &s, int priority = 0);
 
+	Common::String getScreenshotsPath() override;
+
 protected:
 	/**
 	 * Base string for creating the default path and filename for the
@@ -64,6 +66,8 @@ protected:
 
 	virtual Common::WriteStream *createLogFile();
 
+	Common::String getXdgUserDir(const char *name);
+
 	virtual AudioCDManager *createAudioCDManager();
 
 	bool launchBrowser(const Common::String& client, const Common::String &url);