Initial revision

Demo/stdwin/ibrowse/icache.py

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+# Cache management for info file processing.
+# The function get_node() is the standard interface;
+# its signature is the same as ifile.get_node() but it uses
+# the cache and supports indirect tag tables.
+
+
+import string
+import ifile
+from ifile import NoSuchNode, NoSuchFile
+import itags
+
+
+# Special hack to save the cache when using reload().
+# This can just be "cache = {}" in a production version.
+#
+try:
+	dummy = cache
+	del dummy
+except NameError:
+	cache = {}
+
+
+# Clear the entire cache.
+#
+def resetcache():
+	for key in cache.keys():
+		del cache[key]
+
+
+# Clear the node info from the cache (the most voluminous data).
+#
+def resetnodecache():
+	for key in cache.keys():
+		tags, nodes = cache[key]
+		cache[key] = tags, {}
+
+
+# Get a node.
+#
+def get_node(curfile, ref):
+	file, node = ifile.parse_ref(curfile, ref)
+	file = string.lower(file)
+	node = string.lower(node)
+	if node == '*':
+		# Don't cache whole file references;
+		# reading the data is faster than displaying it anyway.
+		return ifile.get_whole_file(file) # May raise NoSuchFile
+	if not cache.has_key(file):
+		cache[file] = get_tags(file), {} # May raise NoSuchFile
+	tags, nodes = cache[file]
+	if not nodes.has_key(node):
+		if not tags.has_key(node):
+			raise NoSuchNode, ref
+		file1, offset, line = tags[node]
+		if not file1:
+			file1 = file
+		file1, node1, header, menu, footnotes, text = \
+			ifile.get_file_node(file1, offset, node)
+		nodes[node] = file, node1, header, menu, footnotes, text
+	return nodes[node]
+
+
+# Get the tag table for a file.
+# Either construct one or get the one found in the file.
+# Raise NoSuchFile if the file isn't found.
+#
+def get_tags(file):
+	f = ifile.try_open(file) # May raise NoSuchFile
+	tags = itags.get_tags(f)
+	if not tags:
+		###print 'Scanning file...'
+		f.seek(0)
+		tags = ifile.make_tags(f)
+	return tags