fix timezones in darcs-fast-export, take 2

The previous patch had a flaw; it assumed that darcs was storing the committer's timezone.
Instead, darcs always stores UTC timestamps in an ISO 8601 format.
Tools like "darcs changes" convert this into the user's local time as a convenience.

I couldn't find an authoritative spec, but here are some relevant references.
http://wiki.darcs.net/NamedPatch
http://search.cpan.org/~david/Darcs-Inventory-1.4/lib/Darcs/Inventory/Patch.pm
http://bugs.darcs.net/issue140

To resolve the issue, this patch always reports that the timezone is UTC.

1 files changed, 10 insertions, 19 deletions

diff --git a/exporters/darcs/darcs-fast-export b/exporters/darcs/darcs-fast-export
index 79590a6..fa850de 100755
--- a/exporters/darcs/darcs-fast-export
+++ b/exporters/darcs/darcs-fast-export
@@ -29,6 +29,7 @@ import os
 import sys
 import gzip
 import time
+import calendar
 import shutil
 import subprocess
 import optparse
@@ -82,22 +83,12 @@ class Handler:
 			author = author[author.index('>')+2:] + ' ' + author[:author.index('>')+1]
 		return author.encode('utf-8')
 
-	def get_time_info(self, patch):
-		date = time.strptime(patch, "%a %b %d %H:%M:%S %Z %Y")
-		timestamp = int(time.mktime(date))
-		# calculate the timezone offset
-		fields=re.split('[ ]+', patch)
-		fields[4]="UTC"
-		patch_utc=" ".join(fields)
-		date_utc=time.strptime(patch_utc, "%a %b %d %H:%M:%S %Z %Y")
-		offset=int(time.timezone + time.mktime(date) - time.mktime(date_utc))
-		hours, minutes = divmod(abs(offset), 3600)
-		if offset > 0:
-			sign = "-"
-		else:
-			sign = "+"
-		zone = "%s%02d%02d" % (sign, hours, minutes // 60)
-		return timestamp, zone
+	def get_date(self, patch):
+		try:
+			date = time.strptime(patch, "%Y%m%d%H%M%S")
+		except ValueError:
+			date = time.strptime(patch[:19] + patch[-5:], '%a %b %d %H:%M:%S %Y')
+		return calendar.timegm(date)
 
 	def progress(self, s):
 		print "progress [%s] %s" % (time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()), s)
@@ -329,8 +320,8 @@ class Handler:
 			print "mark :%s" % markcount
 			if self.options.export_marks:
 				self.export_marks.append(":%s %s" % (markcount, hash))
-			date, zone = self.get_time_info(i.attributes['local_date'].value)
-			print "committer %s %s %s" % (self.get_author(i), date, zone)
+			date = self.get_date(i.attributes['date'].value)
+			print "committer %s %s +0000" % (self.get_author(i), date)
 			print "data %d\n%s" % (len(message), message)
 			if markcount > 1:
 				print "from :%s" % (markcount-1)
@@ -354,7 +345,7 @@ class Handler:
 				tag = re.sub('[^\xe9-\xf8\w.\-]+', '_', message[4:].strip().split('\n')[0]).strip('_')
 				print "tag %s" % tag
 				print "from :%s" % markcount
-				print "tagger %s %s %s" % (self.get_author(i), date, zone)
+				print "tagger %s %s +0000" % (self.get_author(i), date)
 				print "data %d\n%s" % (len(message), message)
 			if count % self.prognum == 0:
 				self.progress("%d/%d patches" % (count, patchnum))