largefiles: use readasstandin() to read hex hash directly from filectx

BTW, C implementation of hexdigest() for SHA-1/256/512 returns hex
hash in lower case, and doctest in Python standard hashlib assumes
that, too. But it isn't explicitly described in API document or so.

Therefore, we can't assume that hexdigest() always returns hex hash in
lower case, for any hash algorithms, on any Python runtimes and
versions.

From point of view of that, it is reasonable for portability that
40800668e019 applies lower() on hex hash in overridefilemerge().

But on the other hand, in largefiles extension, there are still many
code paths comparing between hex hashes or storing hex hash into
standin file, without lower().

Switching to hash algorithm other than SHA-1 may be good chance to
clarify our policy about hexdigest()-ed hash value string.

  - assume that hexdigest() always returns hex hash in lower case, or

  - apply lower() on hex hash in appropriate layers to ensure
    lower-case-ness of it for portability

hgext/largefiles/basestore.py

@@ -130,7 +130,7 b' class basestore(object):'
                     key = (filename, fctx.filenode())
                     if key not in verified:
                         verified.add(key)
-                        expectedhash = fctx.data().strip()
+                        expectedhash = lfutil.readasstandin(fctx)
                         filestocheck.append((cset, filename, expectedhash))
 
         failed = self._verifyfiles(contents, filestocheck)

hgext/largefiles/lfcommands.py

@@ -406,7 +406,7 b' def cachelfiles(ui, repo, node, filelist'
     ctx = repo[node]
     for lfile in lfiles:
         try:
-            expectedhash = ctx[lfutil.standin(lfile)].data().strip()
+            expectedhash = lfutil.readasstandin(ctx[lfutil.standin(lfile)])
         except IOError as err:
             if err.errno == errno.ENOENT:
                 continue # node must be None and standin wasn't found in wctx

hgext/largefiles/lfutil.py

@@ -174,7 +174,7 b' def lfdirstatestatus(lfdirstate, repo):'
             fctx = pctx[standin(lfile)]
         except LookupError:
             fctx = None
-        if not fctx or fctx.data().strip() != hashfile(repo.wjoin(lfile)):
+        if not fctx or readasstandin(fctx) != hashfile(repo.wjoin(lfile)):
             modified.append(lfile)
         else:
             clean.append(lfile)
@@ -528,7 +528,7 b' def getlfilestoupload(repo, missing, add'
                     files.add(f)
         for fn in files:
             if isstandin(fn) and fn in ctx:
-                addfunc(fn, ctx[fn].data().strip())
+                addfunc(fn, readasstandin(ctx[fn]))
     repo.ui.progress(_('finding outgoing largefiles'), None)
 
 def updatestandinsbymatch(repo, match):

hgext/largefiles/overrides.py

@@ -553,9 +553,9 b' def overridefilemerge(origfn, premerge, '
         return origfn(premerge, repo, mynode, orig, fcd, fco, fca,
                       labels=labels)
 
-    ahash = fca.data().strip().lower()
-    dhash = fcd.data().strip().lower()
-    ohash = fco.data().strip().lower()
+    ahash = lfutil.readasstandin(fca).lower()
+    dhash = lfutil.readasstandin(fcd).lower()
+    ohash = lfutil.readasstandin(fco).lower()
     if (ohash != ahash and
         ohash != dhash and
         (dhash == ahash or

hgext/largefiles/reposetup.py

@@ -172,7 +172,7 b' def reposetup(ui, repo):'
                             if standin not in ctx1:
                                 # from second parent
                                 modified.append(lfile)
-                            elif ctx1[standin].data().strip() \
+                            elif lfutil.readasstandin(ctx1[standin]) \
                                     != lfutil.hashfile(self.wjoin(lfile)):
                                 modified.append(lfile)
                             else:
@@ -188,7 +188,7 b' def reposetup(ui, repo):'
                             standin = lfutil.standin(lfile)
                             if standin in ctx1:
                                 abslfile = self.wjoin(lfile)
-                                if ((ctx1[standin].data().strip() !=
+                                if ((lfutil.readasstandin(ctx1[standin]) !=
                                      lfutil.hashfile(abslfile)) or
                                     (checkexec and
                                      ('x' in ctx1.flags(standin)) !=