cpython/Demo/stdwin/ibrowse/icache.py

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Python
Executable File

# 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