Started working on incremental imports from Perforce.

Try to find the last imported p4 change number from the git tags and try to pass the right parent for commits to git fast-import.

Signed-off-by: Simon Hausmann <hausmann@kde.org>

contrib/fast-import/p4-fast-export.py

@@ -26,6 +26,8 @@ if len(sys.argv) != 2:
     print ""
     sys.exit(1)
 
+master = "refs/heads/p4"
+branch = "refs/heads/p4-import"
 prefix = sys.argv[1]
 changeRange = ""
 try:
@@ -70,6 +72,25 @@ def getUserMap():
     return users
 
 users = getUserMap()
+topMerge = ""
+
+incremental = 0
+# try incremental import
+if len(changeRange) == 0:
+    try:
+        sout, sin, serr = popen2.popen3("git-name-rev --tags `git-rev-parse %s`" % master)
+        output = sout.read()
+        tagIdx = output.index(" tags/p4/")
+        caretIdx = output.index("^")
+        revision = int(output[tagIdx + 9 : caretIdx]) + 1
+        changeRange = "@%s,#head" % revision
+        topMerge = os.popen("git-rev-parse %s" % master).read()[:-1]
+        incremental = 1
+    except:
+        pass
+
+if incremental == 0:
+    branch = master
 
 output = os.popen("p4 changes %s...%s" % (prefix, changeRange)).readlines()
 
@@ -80,6 +101,10 @@ for line in output:
 
 changes.reverse()
 
+if len(changes) == 0:
+    print "no changes to import!"
+    sys.exit(1)
+
 sys.stderr.write("\n")
 
 tz = - time.timezone / 36
@@ -97,7 +122,7 @@ for change in changes:
     epoch = description["time"]
     author = description["user"]
 
-    gitStream.write("commit refs/heads/master\n")
+    gitStream.write("commit %s\n" % branch)
     committer = ""
     if author in users:
         committer = "%s %s %s" % (users[author], epoch, tz)
@@ -111,6 +136,10 @@ for change in changes:
     gitStream.write("\n[ imported from %s; change %s ]\n" % (prefix, change))
     gitStream.write("EOT\n\n")
 
+    if len(topMerge) > 0:
+        gitStream.write("merge %s\n" % topMerge)
+        topMerge = ""
+
     fnum = 0
     while description.has_key("depotFile%s" % fnum):
         path = description["depotFile%s" % fnum]
@@ -143,7 +172,7 @@ for change in changes:
     gitStream.write("\n")
 
     gitStream.write("tag p4/%s\n" % change)
-    gitStream.write("from refs/heads/master\n");
+    gitStream.write("from %s\n" % branch);
     gitStream.write("tagger %s\n" % committer);
     gitStream.write("data 0\n\n")
 
@@ -152,4 +181,8 @@ gitStream.close()
 gitOutput.close()
 gitError.close()
 
+if incremental == 1:
+    os.popen("git rebase p4-import p4")
+    os.popen("git branch -d p4-import")
+
 print ""