logcmdutil: unindent diff generator of changesetprinter

Prepares for the next few patches which will make matchfn and hunksfilterfn
always available.

mercurial/logcmdutil.py

@@ -282,7 +282,8 b' class changesetprinter(object):'
     def _showpatch(self, ctx):
         matchfn = self._makefilematcher(ctx)
         hunksfilterfn = self._makehunksfilter(ctx)
-        if matchfn:
+        if not matchfn:
+            return
             stat = self.diffopts.get('stat')
             diff = self.diffopts.get('patch')
             diffopts = patch.diffallopts(self.ui, self.diffopts)
@@ -292,9 +293,9 b' class changesetprinter(object):'
                 diffordiffstat(self.ui, self.repo, diffopts, prev, node,
                                match=matchfn, stat=True,
                                hunksfilterfn=hunksfilterfn)
+        if stat and diff:
+            self.ui.write("\n")
             if diff:
-                if stat:
-                    self.ui.write("\n")
                 diffordiffstat(self.ui, self.repo, diffopts, prev, node,
                                match=matchfn, stat=False,
                                hunksfilterfn=hunksfilterfn)
@@ -383,18 +384,17 b' class jsonchangeset(changesetprinter):'
                                                         for k, v in copies))
 
         matchfn = self._makefilematcher(ctx)
-        if matchfn:
             stat = self.diffopts.get('stat')
             diff = self.diffopts.get('patch')
             diffopts = patch.difffeatureopts(self.ui, self.diffopts, git=True)
             node, prev = ctx.node(), ctx.p1().node()
-            if stat:
+        if matchfn and stat:
                 self.ui.pushbuffer()
                 diffordiffstat(self.ui, self.repo, diffopts, prev, node,
                                match=matchfn, stat=True)
                 self.ui.write((',\n  "diffstat": "%s"')
                               % j(self.ui.popbuffer()))
-            if diff:
+        if matchfn and diff:
                 self.ui.pushbuffer()
                 diffordiffstat(self.ui, self.repo, diffopts, prev, node,
                                match=matchfn, stat=False)