tersestatus: avoid modifying tersedict

tersestatus: avoid modifying tersedict

Turn dirnode's methods into generators which can be used to update "tersedict"
in caller. So instead of passing the "tersedict" to be mutated here and there,
it's now clearer where it is updated as it's purely a local variable to
tersedir() function.

While I was here, I renamed _processtersestatus to tersewalk and
_addfilestotersed to iterfilepaths.

Differential Revision: https://phab.mercurial-scm.org/D1043

--- a/mercurial/cmdutil.py	Wed Oct 11 21:19:19 2017 +0200
+++ b/mercurial/cmdutil.py	Fri Oct 13 04:02:06 2017 +0530
@@ -462,19 +462,17 @@
         if status not in self.statuses:
             self.statuses.add(status)
 
-    def _addfilestotersed(self, tersedict):
+    def iterfilepaths(self):
         """
         adds files to the their respective status list in the final tersed list
 
         path is the path of parent directory of the file
         files is a list of tuple where each tuple is (filename, status)
-        tersedict is a dictonary which contains each status abbreviation as key and
-        list of files and tersed dirs in that status as value
         """
         for f, st in self.files:
-            tersedict[st].append(os.path.join(self.path, f))
-
-    def _processtersestatus(self, tersedict, terseargs):
+            yield st, os.path.join(self.path, f)
+
+    def tersewalk(self, terseargs):
         """
         a recursive function which process status for a certain directory.
 
@@ -494,12 +492,12 @@
 
         1) All the files in the directory (including all the files in its
         subdirectories) share the same status and the user has asked us to terse
-        that status. -> we add the directory name to status list and return
+        that status. -> yield (status, dirpath)
 
         2) If '1)' does not happen, we do following:
 
-                a) Add all the files which are in this directory (only the ones in
-                    this directory, not the subdirs) to their respective status list
+                a) Yield (status, filepath)  for all the files which are in this
+                    directory (only the ones in this directory, not the subdirs)
 
                 b) Recurse the function on all the subdirectories of this
                    directory
@@ -511,15 +509,17 @@
             # Making sure we terse only when the status abbreviation is
             # passed as terse argument
             if onlyst in terseargs:
-                tersedict[onlyst].append(self.path + pycompat.ossep)
+                yield onlyst, self.path + pycompat.ossep
                 return
 
         # add the files to status list
-        self._addfilestotersed(tersedict)
+        for st, fpath in self.iterfilepaths():
+            yield st, fpath
 
         #recurse on the subdirs
         for dirobj in self.subdirs.values():
-            dirobj._processtersestatus(tersedict, terseargs)
+            for st, fpath in dirobj.tersewalk(terseargs):
+                yield st, fpath
 
 def tersedir(statuslist, terseargs):
     """
@@ -536,7 +536,7 @@
 
     tersedict (defined in the function) is a dictionary which has one word key
     for each status and a list of files and dir in that status as the respective
-    value. The dictionary is passed to other helper functions which builds it.
+    value.
     """
     # the order matters here as that is used to produce final list
     allst = ('m', 'a', 'r', 'd', 'u', 'i', 'c')
@@ -558,11 +558,13 @@
         tersedict[attrname[0]] = []
 
     # we won't be tersing the root dir, so add files in it
-    rootobj._addfilestotersed(tersedict)
+    for st, fpath in rootobj.iterfilepaths():
+        tersedict[st].append(fpath)
 
     # process each sub-directory and build tersedict
     for subdir in rootobj.subdirs.values():
-        subdir._processtersestatus(tersedict, terseargs)
+        for st, f in subdir.tersewalk(terseargs):
+            tersedict[st].append(f)
 
     tersedlist = []
     for st in allst: