Preferences is a general module to get (and set) preferences in

resource files with various inheritence rules, parsers, etc.

pythonprefs uses this to create a single uniform interface to all
relevant python preferences.

1 files changed, 219 insertions, 0 deletions

diff --git a/Mac/Lib/preferences.py b/Mac/Lib/preferences.py
new file mode 100644
index 0000000..810d9cc
--- /dev/null
+++ b/Mac/Lib/preferences.py
@@ -0,0 +1,219 @@
+#
+# General parser/loaders for preferences files and such
+#
+import Res
+import macfs
+import struct
+import MACFS
+
+READ=1
+READWRITE=3
+Error = "Preferences.Error"
+
+debug = 0
+
+class NullLoader:
+	def __init__(self, data=None):
+		self.data = data
+		
+	def load(self):
+		if self.data is None:
+			raise Error, "No default given"
+		return self.data
+		
+	def save(self, data):
+		raise Error, "Cannot save to default value"
+		
+	def delete(self, deep=0):
+		if debug:
+			print 'Attempt to delete default value'
+		raise Error, "Cannot delete default value"
+		
+_defaultdefault = NullLoader()
+		
+class ResLoader:
+	def __init__(self, filename, resid, resnum=None, resname=None, default=_defaultdefault):
+		self.filename = filename
+		self.fss = macfs.FSSpec(self.filename)
+		self.resid = resid
+		self.resnum = resnum
+		self.resname = resname
+		self.default = default
+		self.data = None
+		
+	def load(self):
+		oldrh = Res.CurResFile()
+		try:
+			rh = Res.FSpOpenResFile(self.fss, READ)
+		except Res.Error:
+			self.data = self.default.load()
+			return self.data
+		try:
+			if self.resname:
+				handle = Res.Get1NamedResource(self.resid, self.resname)
+			else:
+				handle = Res.Get1Resource(self.resid, self.resnum)
+		except Res.Error:
+			self.data = self.default.load()
+		else:
+			if debug:
+				print 'Loaded', (self.resid, self.resnum, self.resname), 'from', self.fss.as_pathname()
+			self.data = handle.data
+		Res.CloseResFile(rh)
+		Res.UseResFile(oldrh)
+		return self.data
+		
+	def save(self, data):
+		if self.data is None or self.data != data:
+			oldrh = Res.CurResFile()
+			rh = Res.FSpOpenResFile(self.fss, READWRITE)
+			try:
+				handle = Res.Get1Resource(self.resid, self.resnum)
+			except Res.Error:
+				handle = Res.Resource(data)
+				handle.AddResource(self.resid, self.resnum, '')
+				if debug:
+					print 'Added', (self.resid, self.resnum), 'to', self.fss.as_pathname()
+			else:
+				handle.data = data
+				handle.ChangedResource()
+				if debug:
+					print 'Changed', (self.resid, self.resnum), 'in', self.fss.as_pathname()
+			Res.CloseResFile(rh)
+			Res.UseResFile(oldrh)
+			
+	def delete(self, deep=0):
+		if debug:
+			print 'Deleting in', self.fss.as_pathname(), `self.data`, deep
+		oldrh = Res.CurResFile()
+		rh = Res.FSpOpenResFile(self.fss, READWRITE)
+		try:
+			handle = Res.Get1Resource(self.resid, self.resnum)
+		except Res.Error:
+			if 	deep:
+				if debug: print 'deep in', self.default
+				self.default.delete(1)
+		else:
+			handle.RemoveResource()
+			if debug:
+				print 'Deleted', (self.resid, self.resnum), 'from', self.fss.as_pathname()
+		self.data = None
+		Res.CloseResFile(rh)
+		Res.UseResFile(oldrh)
+
+class AnyResLoader:
+	def __init__(self, resid, resnum=None, resname=None, default=_defaultdefault):
+		self.resid = resid
+		self.resnum = resnum
+		self.resname = resname
+		self.default = default
+		self.data = None
+		
+	def load(self):
+		try:
+			if self.resname:
+				handle = Res.GetNamedResource(self.resid, self.resname)
+			else:
+				handle = Res.GetResource(self.resid, self.resnum)
+		except Res.Error:
+			self.data = self.default.load()
+		else:
+			self.data = handle.data
+		return self.data
+		
+	def save(self, data):
+		raise Error, "Cannot save AnyResLoader preferences"
+					
+	def delete(self, deep=0):
+		raise Error, "Cannot delete AnyResLoader preferences"
+			
+class StructLoader:
+	def __init__(self, format, loader):
+		self.format = format
+		self.loader = loader
+		
+	def load(self):
+		data = self.loader.load()
+		return struct.unpack(self.format, data)
+		
+	def save(self, data):
+		data = apply(struct.pack, (self.format,)+data)
+		self.loader.save(data)
+		
+	def delete(self, deep=0):
+		self.loader.delete(deep)
+		
+class PstringLoader:
+	def __init__(self, loader):
+		self.loader = loader
+		
+	def load(self):
+		data = self.loader.load()
+		len = ord(data[0])
+		return data[1:1+len]
+		
+	def save(self, data):
+		if len(data) > 255:
+			raise Error, "String too big for pascal-style"
+		self.loader.save(chr(len(data))+data)
+		
+	def delete(self, deep=0):
+		self.loader.delete(deep)
+		
+class VersionLoader(StructLoader):
+	def load(self):
+		while 1:
+			data = self.loader.load()
+			if debug:
+				print 'Versionloader:', `data`
+			try:
+				rv = struct.unpack(self.format, data)
+				rv = self.versioncheck(rv)
+				return rv
+			except (struct.error, Error):
+				self.delete(1)
+				
+	def versioncheck(self, data):
+		return data
+		
+class StrListLoader:
+	def __init__(self, loader):
+		self.loader = loader
+		
+	def load(self):
+		data = self.loader.load()
+		num, = struct.unpack('h', data[:2])
+		data = data[2:]
+		rv = []
+		for i in range(num):
+			strlen = ord(data[0])
+			if strlen < 0: strlen = strlen + 256
+			str = data[1:strlen+1]
+			data = data[strlen+1:]
+			rv.append(str)
+		return rv
+
+	def save(self, list):
+		rv = struct.pack('h', len(list))
+		for str in list:
+			rv = rv + chr(len(str)) + str
+		self.loader.save(rv)
+		
+	def delete(self, deep=0):
+		self.loader.delete(deep)
+
+def preferencefile(filename, creator=None, type=None):
+	create = creator != None and type != None
+	vrefnum, dirid = macfs.FindFolder(MACFS.kOnSystemDisk, 'pref', create)
+	fss = macfs.FSSpec((vrefnum, dirid, filename))
+	oldrf = Res.CurResFile()
+	if create:
+		try:
+			rh = Res.FSpOpenResFile(fss, READ)
+		except Res.Error:
+			Res.FSpCreateResFile(fss, creator, type, MACFS.smAllScripts)
+		else:
+			Res.CloseResFile(rh)
+			Res.UseResFile(oldrf)
+	return fss
+