# HG changeset patch
# User Matt Mackall <mpm@selenic.com>
# Date 1151532466 18000
# Node ID 482c524dd9ab2c9fca8e8fcf38ff0f9ff21b126b
# Parent  a020024c5870b492dfdd13af596c675e4273e58c
Add context.py: changeset and file revision contexts

diff --git a/mercurial/context.py b/mercurial/context.py
new file mode 100644
--- /dev/null
+++ b/mercurial/context.py
@@ -0,0 +1,121 @@
+# context.py - changeset and file context objects for mercurial
+#
+# Copyright 2005 Matt Mackall <mpm@selenic.com>
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+
+class changectx(object):
+    """A changecontext object makes access to data related to a particular
+    changeset convenient."""
+    def __init__(self, repo, changeid):
+        """changeid is a revision number, node, or tag"""
+        self._repo = repo
+        self._id = changeid
+
+        self._node = self._repo.lookup(self._id)
+        self._rev = self._repo.changelog.rev(self._node)
+
+    def changeset(self):
+        try:
+            return self._changeset
+        except AttributeError:
+            self._changeset = self._repo.changelog.read(self.node())
+            return self._changeset
+
+    def manifest(self):
+        try:
+            return self._manifest
+        except AttributeError:
+            self._manifest = self._repo.manifest.read(self.changeset()[0])
+            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 changedfiles(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)
+        return node
+
+    def filectx(self, path):
+        """get a file context from this changeset"""
+        return filectx(self._repo, path, fileid=self.filenode(path))
+
+    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])
+
+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):
+        """changeid can be a changeset revision, node, or tag.
+           fileid can be a file revision or node."""
+        self._repo = repo
+        self._path = path
+        self._id = changeid
+        self._fileid = fileid
+
+        if self._id:
+            # if given a changeset id, go ahead and look up the file
+            self._changeset = changectx(repo, self._id)
+            node, flag = self._repo.manifest.find(self._changeset[0], path)
+            self._node = node
+            self._filelog = self.repo.file(self._path)
+        elif self._fileid:
+            # else be lazy
+            self._filelog = self._repo.file(self._path)
+            self._filenode = self._filelog.lookup(self._fileid)
+        self._filerev = self._filelog.rev(self._filenode)
+
+    def changeset(self):
+        try:
+            return self._changeset
+        except AttributeError:
+            self._changeset = self._repo.changelog.read(self.node())
+            return self._changeset
+
+    def filerev(self): return self._filerev
+    def filenode(self): return self._filenode
+    def filelog(self): return self._filelog
+
+    def rev(self): return self.changeset().rev()
+    def node(self): return self.changeset().node()
+    def user(self): return self.changeset().user()
+    def date(self): return self.changeset().date()
+    def files(self): return self.changeset().files()
+    def description(self): return self.changeset().description()
+    def manifest(self): return self.changeset().manifest()
+
+    def data(self): return self._filelog.read(self._filenode)
+    def metadata(self): return self._filelog.readmeta(self._filenode)
+    def renamed(self): return self._filelog.renamed(self._filenode)
+
+    def parents(self):
+        # need to fix for renames
+        p = self._filelog.parents(self._filenode)
+        return [ filectx(self._repo, self._path, fileid=x) for x in p ]
+
+    def children(self):
+        # hard for renames
+        c = self._filelog.children(self._filenode)
+        return [ filectx(self._repo, self._path, fileid=x) for x in c ]