filemerge: refactoring of 'filemerge()'

current 'filemerge.filemerge()' implementation is verfy complicated.

    - it is not easy to add new internal merge tools
      (only by patching on 'filemerge()', or replacing it completely)

    - cleanup of temporary files is unsatisfactory
      ('internal:dump' does not, in fact)

this is patch for refactoring of 'filemerge()' to isolate each
internal merge tool implementations from 'filemerge()', and clean up
common part in it.

mercurial/filemerge.py

@@ -1,269 +1,342 b''
 # filemerge.py - file-level merge handling for Mercurial
 #
 # Copyright 2006, 2007, 2008 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from node import short
 from i18n import _
 import util, simplemerge, match, error
 import os, tempfile, re, filecmp
 
 def _toolstr(ui, tool, part, default=""):
     return ui.config("merge-tools", tool + "." + part, default)
 
 def _toolbool(ui, tool, part, default=False):
     return ui.configbool("merge-tools", tool + "." + part, default)
 
 def _toollist(ui, tool, part, default=[]):
     return ui.configlist("merge-tools", tool + "." + part, default)
 
-_internal = ['internal:' + s
-             for s in 'fail local other merge prompt dump'.split()]
+_internal = {}
+
+def internaltool(name, trymerge, onfailure=None):
+    '''return a decorator for populating internal merge tool table'''
+    def decorator(func):
+        _internal[name] = func
+        func.trymerge = trymerge
+        func.onfailure = onfailure
+        return func
+    return decorator
 
 def _findtool(ui, tool):
     if tool in _internal:
         return tool
     for kn in ("regkey", "regkeyalt"):
         k = _toolstr(ui, tool, kn)
         if not k:
             continue
         p = util.lookupreg(k, _toolstr(ui, tool, "regname"))
         if p:
             p = util.findexe(p + _toolstr(ui, tool, "regappend"))
             if p:
                 return p
     exe = _toolstr(ui, tool, "executable", tool)
     return util.findexe(util.expandpath(exe))
 
 def _picktool(repo, ui, path, binary, symlink):
     def check(tool, pat, symlink, binary):
         tmsg = tool
         if pat:
             tmsg += " specified for " + pat
         if not _findtool(ui, tool):
             if pat: # explicitly requested tool deserves a warning
                 ui.warn(_("couldn't find merge tool %s\n") % tmsg)
             else: # configured but non-existing tools are more silent
                 ui.note(_("couldn't find merge tool %s\n") % tmsg)
         elif symlink and not _toolbool(ui, tool, "symlink"):
             ui.warn(_("tool %s can't handle symlinks\n") % tmsg)
         elif binary and not _toolbool(ui, tool, "binary"):
             ui.warn(_("tool %s can't handle binary\n") % tmsg)
         elif not util.gui() and _toolbool(ui, tool, "gui"):
             ui.warn(_("tool %s requires a GUI\n") % tmsg)
         else:
             return True
         return False
 
     # forcemerge comes from command line arguments, highest priority
     force = ui.config('ui', 'forcemerge')
     if force:
         toolpath = _findtool(ui, force)
         if toolpath:
             return (force, '"' + toolpath + '"')
         else:
             # mimic HGMERGE if given tool not found
             return (force, force)
 
     # HGMERGE takes next precedence
     hgmerge = os.environ.get("HGMERGE")
     if hgmerge:
         return (hgmerge, hgmerge)
 
     # then patterns
     for pat, tool in ui.configitems("merge-patterns"):
         mf = match.match(repo.root, '', [pat])
         if mf(path) and check(tool, pat, symlink, False):
             toolpath = _findtool(ui, tool)
             return (tool, '"' + toolpath + '"')
 
     # then merge tools
     tools = {}
     for k, v in ui.configitems("merge-tools"):
         t = k.split('.')[0]
         if t not in tools:
             tools[t] = int(_toolstr(ui, t, "priority", "0"))
     names = tools.keys()
     tools = sorted([(-p, t) for t, p in tools.items()])
     uimerge = ui.config("ui", "merge")
     if uimerge:
         if uimerge not in names:
             return (uimerge, uimerge)
         tools.insert(0, (None, uimerge)) # highest priority
     tools.append((None, "hgmerge")) # the old default, if found
     for p, t in tools:
         if check(t, None, symlink, binary):
             toolpath = _findtool(ui, t)
             return (t, '"' + toolpath + '"')
     # internal merge as last resort
     return (not (symlink or binary) and "internal:merge" or None, None)
 
 def _eoltype(data):
     "Guess the EOL type of a file"
     if '\0' in data: # binary
         return None
     if '\r\n' in data: # Windows
         return '\r\n'
     if '\r' in data: # Old Mac
         return '\r'
     if '\n' in data: # UNIX
         return '\n'
     return None # unknown
 
 def _matcheol(file, origfile):
     "Convert EOL markers in a file to match origfile"
     tostyle = _eoltype(util.readfile(origfile))
     if tostyle:
         data = util.readfile(file)
         style = _eoltype(data)
         if style:
             newdata = data.replace(style, tostyle)
             if newdata != data:
                 util.writefile(file, newdata)
 
+@internaltool('internal:prompt', False)
+def _iprompt(repo, mynode, orig, fcd, fco, fca, toolconf):
+    ui = repo.ui
+    fd = fcd.path()
+
+    if ui.promptchoice(_(" no tool found to merge %s\n"
+                         "keep (l)ocal or take (o)ther?") % fd,
+                       (_("&Local"), _("&Other")), 0):
+        return _iother(repo, mynode, orig, fcd, fco, fca, toolconf)
+    else:
+        return _ilocal(repo, mynode, orig, fcd, fco, fca, toolconf)
+
+@internaltool('internal:local', False)
+def _ilocal(repo, mynode, orig, fcd, fco, fca, toolconf):
+    return 0
+
+@internaltool('internal:other', False)
+def _iother(repo, mynode, orig, fcd, fco, fca, toolconf):
+    repo.wwrite(fcd.path(), fco.data(), fco.flags())
+    return 0
+
+@internaltool('internal:fail', False)
+def _ifail(repo, mynode, orig, fcd, fco, fca, toolconf):
+    return 1
+
+def _premerge(repo, toolconf, files):
+    tool, toolpath, binary, symlink = toolconf
+    a, b, c, back = files
+
+    ui = repo.ui
+
+    # do we attempt to simplemerge first?
+    try:
+        premerge = _toolbool(ui, tool, "premerge", not (binary or symlink))
+    except error.ConfigError:
+        premerge = _toolstr(ui, tool, "premerge").lower()
+        valid = 'keep'.split()
+        if premerge not in valid:
+            _valid = ', '.join(["'" + v + "'" for v in valid])
+            raise error.ConfigError(_("%s.premerge not valid "
+                                      "('%s' is neither boolean nor %s)") %
+                                    (tool, premerge, _valid))
+
+    if premerge:
+        r = simplemerge.simplemerge(ui, a, b, c, quiet=True)
+        if not r:
+            ui.debug(" premerge successful\n")
+            return 0
+        if premerge != 'keep':
+            util.copyfile(back, a) # restore from backup and try again
+    return 1 # continue merging
+
+@internaltool('internal:merge', True,
+              _("merging %s incomplete! "
+                "(edit conflicts, then use 'hg resolve --mark')\n"))
+def _imerge(repo, mynode, orig, fcd, fco, fca, toolconf, files):
+    r = _premerge(repo, toolconf, files)
+    if r:
+        a, b, c, back = files
+
+        ui = repo.ui
+
+        r = simplemerge.simplemerge(ui, a, b, c, label=['local', 'other'])
+        return True, r
+    return False, 0
+
+@internaltool('internal:dump', True)
+def _idump(repo, mynode, orig, fcd, fco, fca, toolconf, files):
+    r = _premerge(repo, toolconf, files)
+    if r:
+        a, b, c, back = files
+
+        fd = fcd.path()
+
+        util.copyfile(a, a + ".local")
+        repo.wwrite(fd + ".other", fco.data(), fco.flags())
+        repo.wwrite(fd + ".base", fca.data(), fca.flags())
+    return False, r
+
+def _xmerge(repo, mynode, orig, fcd, fco, fca, toolconf, files):
+    r = _premerge(repo, toolconf, files)
+    if r:
+        tool, toolpath, binary, symlink = toolconf
+        a, b, c, back = files
+        out = ""
+        env = dict(HG_FILE=fcd.path(),
+                   HG_MY_NODE=short(mynode),
+                   HG_OTHER_NODE=str(fco.changectx()),
+                   HG_BASE_NODE=str(fca.changectx()),
+                   HG_MY_ISLINK='l' in fcd.flags(),
+                   HG_OTHER_ISLINK='l' in fco.flags(),
+                   HG_BASE_ISLINK='l' in fca.flags())
+
+        ui = repo.ui
+
+        args = _toolstr(ui, tool, "args", '$local $base $other')
+        if "$output" in args:
+            out, a = a, back # read input from backup, write to original
+        replace = dict(local=a, base=b, other=c, output=out)
+        args = util.interpolate(r'\$', replace, args,
+                                lambda s: '"%s"' % util.localpath(s))
+        r = util.system(toolpath + ' ' + args, cwd=repo.root, environ=env,
+                        out=ui.fout)
+        return True, r
+    return False, 0
+
 def filemerge(repo, mynode, orig, fcd, fco, fca):
     """perform a 3-way merge in the working directory
 
     mynode = parent node before merge
     orig = original local filename before merge
     fco = other file context
     fca = ancestor file context
     fcd = local file context for current/destination file
     """
 
     def temp(prefix, ctx):
         pre = "%s~%s." % (os.path.basename(ctx.path()), prefix)
         (fd, name) = tempfile.mkstemp(prefix=pre)
         data = repo.wwritedata(ctx.path(), ctx.data())
         f = os.fdopen(fd, "wb")
         f.write(data)
         f.close()
         return name
 
     if not fco.cmp(fcd): # files identical?
         return None
 
     ui = repo.ui
     fd = fcd.path()
     binary = fcd.isbinary() or fco.isbinary() or fca.isbinary()
     symlink = 'l' in fcd.flags() + fco.flags()
     tool, toolpath = _picktool(repo, ui, fd, binary, symlink)
     ui.debug("picked tool '%s' for %s (binary %s symlink %s)\n" %
                (tool, fd, binary, symlink))
 
-    if not tool or tool == 'internal:prompt':
-        tool = "internal:local"
-        if ui.promptchoice(_(" no tool found to merge %s\n"
-                             "keep (l)ocal or take (o)ther?") % fd,
-                           (_("&Local"), _("&Other")), 0):
-            tool = "internal:other"
-    if tool == "internal:local":
-        return 0
-    if tool == "internal:other":
-        repo.wwrite(fd, fco.data(), fco.flags())
-        return 0
-    if tool == "internal:fail":
-        return 1
+    if tool in _internal:
+        func = _internal[tool]
+        trymerge = func.trymerge
+        onfailure = func.onfailure
+    else:
+        func = _xmerge
+        trymerge = True
+        onfailure = _("merging %s failed!\n")
 
-    # do the actual merge
+    toolconf = tool, toolpath, binary, symlink
+
+    if not trymerge:
+        return func(repo, mynode, orig, fcd, fco, fca, toolconf)
+
     a = repo.wjoin(fd)
     b = temp("base", fca)
     c = temp("other", fco)
-    out = ""
     back = a + ".orig"
     util.copyfile(a, back)
 
     if orig != fco.path():
         ui.status(_("merging %s and %s to %s\n") % (orig, fco.path(), fd))
     else:
         ui.status(_("merging %s\n") % fd)
 
     ui.debug("my %s other %s ancestor %s\n" % (fcd, fco, fca))
 
-    # do we attempt to simplemerge first?
-    try:
-        premerge = _toolbool(ui, tool, "premerge", not (binary or symlink))
-    except error.ConfigError:
-        premerge = _toolstr(ui, tool, "premerge").lower()
-        valid = 'keep'.split()
-        if premerge not in valid:
-            _valid = ', '.join(["'" + v + "'" for v in valid])
-            raise error.ConfigError(_("%s.premerge not valid "
-                                      "('%s' is neither boolean nor %s)") %
-                                    (tool, premerge, _valid))
-
-    if premerge:
-        r = simplemerge.simplemerge(ui, a, b, c, quiet=True)
-        if not r:
-            ui.debug(" premerge successful\n")
+    needcheck, r = func(repo, mynode, orig, fcd, fco, fca, toolconf,
+                        (a, b, c, back))
+    if not needcheck:
+        if r:
+            if onfailure:
+                ui.warn(onfailure % fd)
+        else:
             os.unlink(back)
-            os.unlink(b)
-            os.unlink(c)
-            return 0
-        if premerge != 'keep':
-            util.copyfile(back, a) # restore from backup and try again
 
-    env = dict(HG_FILE=fd,
-               HG_MY_NODE=short(mynode),
-               HG_OTHER_NODE=str(fco.changectx()),
-               HG_BASE_NODE=str(fca.changectx()),
-               HG_MY_ISLINK='l' in fcd.flags(),
-               HG_OTHER_ISLINK='l' in fco.flags(),
-               HG_BASE_ISLINK='l' in fca.flags())
-
-    if tool == "internal:merge":
-        r = simplemerge.simplemerge(ui, a, b, c, label=['local', 'other'])
-    elif tool == 'internal:dump':
-        a = repo.wjoin(fd)
-        util.copyfile(a, a + ".local")
-        repo.wwrite(fd + ".other", fco.data(), fco.flags())
-        repo.wwrite(fd + ".base", fca.data(), fca.flags())
-        return 1 # unresolved
-    else:
-        args = _toolstr(ui, tool, "args", '$local $base $other')
-        if "$output" in args:
-            out, a = a, back # read input from backup, write to original
-        replace = dict(local=a, base=b, other=c, output=out)
-        args = util.interpolate(r'\$', replace, args,
-                                lambda s: '"%s"' % util.localpath(s))
-        r = util.system(toolpath + ' ' + args, cwd=repo.root, environ=env,
-                        out=ui.fout)
+        os.unlink(b)
+        os.unlink(c)
+        return r
 
     if not r and (_toolbool(ui, tool, "checkconflicts") or
                   'conflicts' in _toollist(ui, tool, "check")):
         if re.search("^(<<<<<<< .*|=======|>>>>>>> .*)$", fcd.data(),
                      re.MULTILINE):
             r = 1
 
     checked = False
     if 'prompt' in _toollist(ui, tool, "check"):
         checked = True
         if ui.promptchoice(_("was merge of '%s' successful (yn)?") % fd,
                            (_("&Yes"), _("&No")), 1):
             r = 1
 
     if not r and not checked and (_toolbool(ui, tool, "checkchanged") or
                                   'changed' in _toollist(ui, tool, "check")):
-        if filecmp.cmp(repo.wjoin(fd), back):
+        if filecmp.cmp(a, back):
             if ui.promptchoice(_(" output file %s appears unchanged\n"
                                  "was merge successful (yn)?") % fd,
                                (_("&Yes"), _("&No")), 1):
                 r = 1
 
     if _toolbool(ui, tool, "fixeol"):
-        _matcheol(repo.wjoin(fd), back)
+        _matcheol(a, back)
 
     if r:
-        if tool == "internal:merge":
-            ui.warn(_("merging %s incomplete! "
-                      "(edit conflicts, then use 'hg resolve --mark')\n") % fd)
-        else:
-            ui.warn(_("merging %s failed!\n") % fd)
+        if onfailure:
+            ui.warn(onfailure % fd)
     else:
         os.unlink(back)
 
     os.unlink(b)
     os.unlink(c)
     return r