Move SettingsHandler to libshared

It's used by both Tracker and Codycam and others might find it useful.

Change-Id: I585d3a1bdc7f8fce7d36bedf6867464cd541ba2e
Reviewed-on: https://review.haiku-os.org/c/1637
Reviewed-by: waddlesplash <[email protected]>

headers/private/shared/SettingsHandler.h

@@ -0,0 +1,179 @@
+/*
+Open Tracker License
+
+Terms and Conditions
+
+Copyright (c) 1991-2000, Be Incorporated. All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice applies to all licensees
+and shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF TITLE, MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+BE INCORPORATED BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF, OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of Be Incorporated shall not be
+used in advertising or otherwise to promote the sale, use or other dealings in
+this Software without prior written authorization from Be Incorporated.
+
+Tracker(TM), Be(R), BeOS(R), and BeIA(TM) are trademarks or registered trademarks
+of Be Incorporated in the United States and other countries. Other brand product
+names are registered trademarks or trademarks of their respective holders.
+All rights reserved.
+*/
+#ifndef _SETTINGS_FILE_H
+#define _SETTINGS_FILE_H
+
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <SupportDefs.h>
+
+
+class BFile;
+class BDirectory;
+class BRect;
+
+namespace BPrivate {
+
+class Settings;
+
+typedef const char* (*ArgvHandler)(int argc, const char* const *argv,
+	void* params);
+	// return 0 or error string if parsing failed
+
+const int32 kBufferSize = 1024;
+
+
+class ArgvParser {
+	// this class opens a text file and passes the context in argv
+	// format to a specified handler
+public:
+	static status_t EachArgv(const char* name,
+		ArgvHandler argvHandlerFunc, void* passThru);
+
+private:
+	ArgvParser(const char* name);
+	~ArgvParser();
+
+	status_t EachArgvPrivate(const char* name,
+		ArgvHandler argvHandlerFunc, void* passThru);
+	char GetCh();
+
+	status_t SendArgv(ArgvHandler argvHandlerFunc, void* passThru);
+		// done with a whole line of argv, send it off and get ready
+		// to build a new one
+
+	void NextArgv();
+		// done with current string, get ready to start building next
+	void NextArgvIfNotEmpty();
+		// as above, don't commint current string if empty
+
+	void MakeArgvEmpty();
+
+	FILE* fFile;
+	char* fBuffer;
+	int32 fPos;
+
+	int fArgc;
+	char** fCurrentArgv;
+
+	int32 fCurrentArgsPos;
+	char fCurrentArgs[1024];
+
+	bool fSawBackslash;
+	bool fEatComment;
+	bool fInDoubleQuote;
+	bool fInSingleQuote;
+
+	int32 fLineNo;
+	const char* fFileName;
+};
+
+
+class SettingsArgvDispatcher {
+	// base class for a single setting item
+public:
+	SettingsArgvDispatcher(const char* name);
+	virtual ~SettingsArgvDispatcher() {};
+
+	void SaveSettings(Settings* settings, bool onlyIfNonDefault);
+
+	const char* Name() const { return fName; }
+		// name as it appears in the settings file
+
+	virtual const char* Handle(const char* const *argv) = 0;
+		// override this adding an argv parser that reads in the
+		// values in argv format for this setting
+		// return a pointer to an error message or null if parsed OK
+
+	// some handy reader/writer calls
+	bool HandleRectValue(BRect&, const char* const *argv,
+		bool printError = true);
+	void WriteRectValue(Settings*, BRect);
+
+protected:
+	virtual void SaveSettingValue(Settings* settings) = 0;
+		// override this to save the current value of this setting in a
+		// text format
+
+	virtual bool NeedsSaving() const { return true; }
+		// override to return false if current value is equal to the default
+		// and does not need saving
+
+private:
+	const char* fName;
+};
+
+
+class Settings {
+	// this class is a list of all the settings handlers, reads and
+	// saves the settings file
+public:
+	Settings(const char* filename, const char* settingsDirName);
+	~Settings();
+	void TryReadingSettings();
+	void SaveSettings(bool onlyIfNonDefault = true);
+
+	bool Add(SettingsArgvDispatcher*);
+		// return false if argv dispatcher with the same name already
+		// registered
+
+	void Write(const char* format, ...);
+	void VSWrite(const char*, va_list);
+
+private:
+	void MakeSettingsDirectory(BDirectory*);
+
+	SettingsArgvDispatcher* Find(const char*);
+	static const char* ParseUserSettings(int, const char* const *argv, void*);
+	void SaveCurrentSettings(bool onlyIfNonDefault);
+
+	const char* fFileName;
+	const char* fSettingsDir;
+		// currently unused
+	SettingsArgvDispatcher** fList;
+	int32 fCount;
+	int32 fListSize;
+	BFile* fCurrentSettings;
+};
+
+}	// namespace BPrivate
+
+using namespace BPrivate;
+
+
+#endif	// _SETTINGS_FILE_H