contexts: use __getattr__ rather than try/except in changectx

mercurial/context.py

@@ -1,302 +1,303
 # context.py - changeset and file context objects for mercurial
 #
 # Copyright 2006 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
 from demandload import *
 from node import *
 demandload(globals(), 'bdiff')
 
 from node import *
 from demandload import demandload
 demandload(globals(), "ancestor util")
 
 class changectx(object):
     """A changecontext object makes access to data related to a particular
     changeset convenient."""
     def __init__(self, repo, changeid=None):
         """changeid is a revision number, node, or tag"""
         self._repo = repo
 
         if not changeid and changeid != 0:
             p1, p2 = self._repo.dirstate.parents()
             self._rev = self._repo.changelog.rev(p1)
             if self._rev == -1:
                 changeid = 'tip'
             else:
                 self._node = p1
                 return
 
         self._node = self._repo.lookup(changeid)
         self._rev = self._repo.changelog.rev(self._node)
 
     def __str__(self):
         return short(self.node())
 
     def __repr__(self):
         return "<changectx %s>" % short(self.node())
 
     def __eq__(self, other):
         return self._rev == other._rev
 
     def __nonzero__(self):
         return self._rev != -1
 
-    def changeset(self):
-        try:
-            return self._changeset
-        except AttributeError:
+    def __getattr__(self, name):
+        if name == '_changeset':
             self._changeset = self._repo.changelog.read(self.node())
             return self._changeset
-
-    def manifest(self):
-        try:
+        elif name == '_manifest':
+            self._manifest = self._repo.manifest.read(self._changeset[0])
             return self._manifest
-        except AttributeError:
-            self._manifest = self._repo.manifest.read(self.changeset()[0])
-            return self._manifest
+        else:
+            raise AttributeError, name
+
+    def changeset(self): return self._changeset
+    def manifest(self): return self._manifest
 
     def rev(self): return self._rev
     def node(self): return self._node
-    def user(self): return self.changeset()[1]
-    def date(self): return self.changeset()[2]
-    def files(self): return self.changeset()[3]
-    def description(self): return self.changeset()[4]
+    def user(self): return self._changeset[1]
+    def date(self): return self._changeset[2]
+    def files(self): return self._changeset[3]
+    def description(self): return self._changeset[4]
 
     def parents(self):
         """return contexts for each parent changeset"""
         p = self._repo.changelog.parents(self._node)
         return [ changectx(self._repo, x) for x in p ]
 
     def children(self):
         """return contexts for each child changeset"""
         c = self._repo.changelog.children(self._node)
         return [ changectx(self._repo, x) for x in c ]
 
     def filenode(self, path):
-        node, flag = self._repo.manifest.find(self.changeset()[0], path)
+        if hasattr(self, "_manifest"):
+            return self._manifest[path]
+        node, flag = self._repo.manifest.find(self._changeset[0], path)
         return node
 
     def filectx(self, path, fileid=None):
         """get a file context from this changeset"""
         if fileid is None:
             fileid = self.filenode(path)
         return filectx(self._repo, path, fileid=fileid, changectx=self)
 
     def filectxs(self):
         """generate a file context for each file in this changeset's
            manifest"""
         mf = self.manifest()
         m = mf.keys()
         m.sort()
         for f in m:
             yield self.filectx(f, fileid=mf[f])
 
     def ancestor(self, c2):
         """
         return the ancestor context of self and c2
         """
         n = self._repo.changelog.ancestor(self._node, c2._node)
         return changectx(self._repo, n)
 
 class filectx(object):
     """A filecontext object makes access to data related to a particular
        filerevision convenient."""
     def __init__(self, repo, path, changeid=None, fileid=None,
                  filelog=None, changectx=None):
         """changeid can be a changeset revision, node, or tag.
            fileid can be a file revision or node."""
         self._repo = repo
         self._path = path
 
         assert changeid is not None or fileid is not None
 
         if filelog:
             self._filelog = filelog
         if changectx:
             self._changectx = changectx
             self._changeid = changectx.node()
 
         if fileid is None:
             self._changeid = changeid
         else:
             self._fileid = fileid
 
     def __getattr__(self, name):
         if name == '_changectx':
             self._changectx = changectx(self._repo, self._changeid)
             return self._changectx
         elif name == '_filelog':
             self._filelog = self._repo.file(self._path)
             return self._filelog
         elif name == '_changeid':
             self._changeid = self._filelog.linkrev(self._filenode)
             return self._changeid
         elif name == '_filenode':
             if hasattr(self, "_fileid"):
                 self._filenode = self._filelog.lookup(self._fileid)
             else:
                 self._filenode = self._changectx.filenode(self._path)
             return self._filenode
         elif name == '_filerev':
             self._filerev = self._filelog.rev(self._filenode)
             return self._filerev
         else:
             raise AttributeError, name
 
     def __nonzero__(self):
         return self._filerev != nullid
 
     def __str__(self):
         return "%s@%s" % (self.path(), short(self.node()))
 
     def __repr__(self):
         return "<filectx %s@%s>" % (self.path(), short(self.node()))
 
     def __eq__(self, other):
         return self._path == other._path and self._changeid == other._changeid
 
     def filectx(self, fileid):
         '''opens an arbitrary revision of the file without
         opening a new filelog'''
         return filectx(self._repo, self._path, fileid=fileid,
                        filelog=self._filelog)
 
     def filerev(self): return self._filerev
     def filenode(self): return self._filenode
     def filelog(self): return self._filelog
 
     def rev(self):
         if hasattr(self, "_changectx"):
             return self._changectx.rev()
         return self._filelog.linkrev(self._filenode)
 
     def node(self): return self._changectx.node()
     def user(self): return self._changectx.user()
     def date(self): return self._changectx.date()
     def files(self): return self._changectx.files()
     def description(self): return self._changectx.description()
     def manifest(self): return self._changectx.manifest()
     def changectx(self): return self._changectx
 
     def data(self): return self._filelog.read(self._filenode)
     def renamed(self): return self._filelog.renamed(self._filenode)
     def path(self): return self._path
 
     def parents(self):
         p = self._path
         fl = self._filelog
         pl = [ (p, n, fl) for n in self._filelog.parents(self._filenode) ]
 
         r = self.renamed()
         if r:
             pl[0] = (r[0], r[1], None)
 
         return [ filectx(self._repo, p, fileid=n, filelog=l)
                  for p,n,l in pl if n != nullid ]
 
     def children(self):
         # hard for renames
         c = self._filelog.children(self._filenode)
         return [ filectx(self._repo, self._path, fileid=x,
                          filelog=self._filelog) for x in c ]
 
     def annotate(self, follow=False):
         '''returns a list of tuples of (ctx, line) for each line
         in the file, where ctx is the filectx of the node where
         that line was last changed'''
 
         def decorate(text, rev):
             return ([rev] * len(text.splitlines()), text)
 
         def pair(parent, child):
             for a1, a2, b1, b2 in bdiff.blocks(parent[1], child[1]):
                 child[0][b1:b2] = parent[0][a1:a2]
             return child
 
         getlog = util.cachefunc(lambda x: self._repo.file(x))
         def getctx(path, fileid):
             log = path == self._path and self._filelog or getlog(path)
             return filectx(self._repo, path, fileid=fileid, filelog=log)
         getctx = util.cachefunc(getctx)
 
         def parents(f):
             # we want to reuse filectx objects as much as possible
             p = f._path
             pl = [ (p, f._filelog.rev(n)) for n in f._filelog.parents(f._filenode) ]
 
             if follow:
                 r = f.renamed()
                 if r:
                     pl[0] = (r[0], getlog(r[0]).rev(r[1]))
 
             return [ getctx(p, n) for p, n in pl if n != -1 ]
                 
         # find all ancestors
         needed = {self: 1}
         visit = [self]
         files = [self._path]
         while visit:
             f = visit.pop(0)
             for p in parents(f):
                 if p not in needed:
                     needed[p] = 1
                     visit.append(p)
                     if p._path not in files:
                         files.append(p._path)
                 else:
                     # count how many times we'll use this
                     needed[p] += 1
 
         # sort by revision (per file) which is a topological order
         visit = []
         files.reverse()
         for f in files:
             fn = [(n._filerev, n) for n in needed.keys() if n._path == f]
             fn.sort()
             visit.extend(fn)
         hist = {}
 
         for r, f in visit:
             curr = decorate(f.data(), f)
             for p in parents(f):
                 if p != nullid:
                     curr = pair(hist[p], curr)
                     # trim the history of unneeded revs
                     needed[p] -= 1
                     if not needed[p]:
                         del hist[p]
             hist[f] = curr
 
         return zip(hist[f][0], hist[f][1].splitlines(1))
 
     def ancestor(self, fc2):
         """
         find the common ancestor file context, if any, of self, and fc2
         """
 
         acache = {}
         flcache = {self._path:self._filelog, fc2._path:fc2._filelog}
         def parents(vertex):
             if vertex in acache:
                 return acache[vertex]
             f, n = vertex
             if f not in flcache:
                 flcache[f] = self._repo.file(f)
             fl = flcache[f]
             pl = [ (f,p) for p in fl.parents(n) if p != nullid ]
             re = fl.renamed(n)
             if re:
                 pl.append(re)
             acache[vertex]=pl
             return pl
 
         a, b = (self._path, self._filenode), (fc2._path, fc2._filenode)
         v = ancestor.ancestor(a, b, parents)
         if v:
             f,n = v
             return filectx(self._repo, f, fileid=n, filelog=flcache[f])
 
         return None