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 @@
     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 @@ def getUserMap():
 
 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 @@ def getUserMap():
     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 @@ def getUserMap():
     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 @@ def getUserMap():
     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 @@ def getUserMap():
 gitOutput.close()
 gitError.close()
 
+if incremental == 1:
+    os.popen("git rebase p4-import p4")
+    os.popen("git branch -d p4-import")
+
 print ""