Demo/stdwin/ibrowse/icache.py

   1 # Cache management for info file processing.
   2 # The function get_node() is the standard interface;
   3 # its signature is the same as ifile.get_node() but it uses
   4 # the cache and supports indirect tag tables.
   5
   6
   7 import string
   8 import ifile
   9 from ifile import NoSuchNode, NoSuchFile
  10 import itags
  11
  12
  13 # Special hack to save the cache when using reload().
  14 # This can just be "cache = {}" in a production version.
  15 #
  16 try:
  17         dummy = cache
  18         del dummy
  19 except NameError:
  20         cache = {}
  21
  22
  23 # Clear the entire cache.
  24 #
  25 def resetcache():
  26         for key in cache.keys():
  27                 del cache[key]
  28
  29
  30 # Clear the node info from the cache (the most voluminous data).
  31 #
  32 def resetnodecache():
  33         for key in cache.keys():
  34                 tags, nodes = cache[key]
  35                 cache[key] = tags, {}
  36
  37
  38 # Get a node.
  39 #
  40 def get_node(curfile, ref):
  41         file, node = ifile.parse_ref(curfile, ref)
  42         file = string.lower(file)
  43         node = string.lower(node)
  44         if node == '*':
  45                 # Don't cache whole file references;
  46                 # reading the data is faster than displaying it anyway.
  47                 return ifile.get_whole_file(file) # May raise NoSuchFile
  48         if not cache.has_key(file):
  49                 cache[file] = get_tags(file), {} # May raise NoSuchFile
  50         tags, nodes = cache[file]
  51         if not nodes.has_key(node):
  52                 if not tags.has_key(node):
  53                         raise NoSuchNode, ref
  54                 file1, offset, line = tags[node]
  55                 if not file1:
  56                         file1 = file
  57                 file1, node1, header, menu, footnotes, text = \
  58                         ifile.get_file_node(file1, offset, node)
  59                 nodes[node] = file, node1, header, menu, footnotes, text
  60         return nodes[node]
  61
  62
  63 # Get the tag table for a file.
  64 # Either construct one or get the one found in the file.
  65 # Raise NoSuchFile if the file isn't found.
  66 #
  67 def get_tags(file):
  68         f = ifile.try_open(file) # May raise NoSuchFile
  69         tags = itags.get_tags(f)
  70         if not tags:
  71                 ###print 'Scanning file...'
  72                 f.seek(0)
  73                 tags = ifile.make_tags(f)
  74         return tags