1 files changed, 134 insertions, 0 deletions
diff --git a/b4/diff.py b/b4/diff.py
new file mode 100644
index 0000000..2d9ebe0
--- /dev/null
+++ b/b4/diff.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2020 by the Linux Foundation
+#
+__author__ = 'Konstantin Ryabitsev <konstantin@linuxfoundation.org>'
+
+import os
+import sys
+import b4
+import b4.mbox
+import mailbox
+from tempfile import mkstemp
+
+
+logger = b4.logger
+
+
+def make_fake_commit_range(gitdir, lser):
+    logger.info('Preparing fake-am for v%s: %s', lser.revision, lser.subject)
+    with b4.git_temp_worktree(gitdir):
+        # We are in a temporary chdir at this time, so writing to a known file should be safe
+        mbxf = '.__git-am__'
+        mbx = mailbox.mbox(mbxf)
+        # Logic largely borrowed from gj_tools
+        seenfiles = set()
+        for lmsg in lser.patches[1:]:
+            logger.debug('Looking at %s', lmsg.full_subject)
+            lmsg.load_hashes()
+            for fn, fi in lmsg.blob_indexes:
+                if fn in seenfiles:
+                    # We already processed this file, so this blob won't match
+                    continue
+                seenfiles.add(fn)
+                if set(fi) == {'0'}:
+                    # New file creation, nothing to do here
+                    logger.debug('  New file: %s', fn)
+                    continue
+                # Try to grab full ref_id of this hash
+                ecode, out = b4.git_run_command(gitdir, ['rev-parse', fi])
+                if ecode > 0:
+                    logger.critical('  ERROR: Could not find matching blob for %s (%s)', fn, fi)
+                    # TODO: better handling
+                    return None, None
+                logger.debug('  Found matching blob for: %s', fn)
+                fullref = out.strip()
+                gitargs = ['update-index', '--add', '--cacheinfo', f'0644,{fullref},{fn}']
+                ecode, out = b4.git_run_command(None, gitargs)
+                if ecode > 0:
+                    logger.critical('  ERROR: Could not run update-index for %s (%s)', fn, fullref)
+                    return None, None
+            mbx.add(lmsg.msg.as_string(policy=b4.emlpolicy).encode('utf-8'))
+
+        mbx.close()
+        ecode, out = b4.git_run_command(None, ['write-tree'])
+        if ecode > 0:
+            logger.critical('ERROR: Could not write fake-am tree')
+            return None, None
+        treeid = out.strip()
+        # At this point we have a worktree with files that should cleanly receive a git am
+        gitargs = ['commit-tree', treeid + '^{tree}', '-F', '-']
+        ecode, out = b4.git_run_command(None, gitargs, stdin='Initial fake commit'.encode('utf-8'))
+        if ecode > 0:
+            logger.critical('ERROR: Could not commit-tree')
+            return None, None
+        start_commit = out.strip()
+        b4.git_run_command(None, ['reset', '--hard', start_commit])
+        ecode, out = b4.git_run_command(None, ['am', mbxf])
+        if ecode > 0:
+            logger.critical('ERROR: Could not fake-am version %s', lser.revision)
+            return None, None
+        ecode, out = b4.git_run_command(None, ['rev-parse', 'HEAD'])
+        end_commit = out.strip()
+        logger.info('  range: %.12s..%.12s', start_commit, end_commit)
+
+    return start_commit, end_commit
+
+
+def main(cmdargs):
+    msgid = b4.get_msgid(cmdargs)
+    if cmdargs.wantvers and len(cmdargs.wantvers) > 2:
+        logger.critical('Can only compare two versions at a time')
+        sys.exit(1)
+
+    # start by grabbing the mbox provided
+    savefile = mkstemp('b4-diff-to')[1]
+    mboxfile = b4.get_pi_thread_by_msgid(msgid, savefile, useproject=cmdargs.useproject, nocache=cmdargs.nocache)
+    if mboxfile is None:
+        logger.critical('Unable to retrieve thread: %s', msgid)
+        return
+    logger.info('Retrieved %s messages in the thread', len(mboxfile))
+    b4.mbox.get_extra_series(mboxfile, direction=-1, wantvers=cmdargs.wantvers)
+    mbx = mailbox.mbox(mboxfile)
+    count = len(mbx)
+    logger.info('---')
+    logger.info('Analyzing %s messages in the thread', count)
+    lmbx = b4.LoreMailbox()
+    for key, msg in mbx.items():
+        lmbx.add_message(msg)
+    if cmdargs.wantvers and len(cmdargs.wantvers) == 1:
+        upper = max(lmbx.series.keys())
+        lower = cmdargs.wantvers[0]
+    elif cmdargs.wantvers and len(cmdargs.wantvers) == 2:
+        upper = max(cmdargs.wantvers)
+        lower = min(cmdargs.wantvers)
+    else:
+        upper = max(lmbx.series.keys())
+        lower = min(lmbx.series.keys())
+
+    if upper not in lmbx.series:
+        logger.critical('Could not find revision %s', upper)
+        sys.exit(1)
+    if lower not in lmbx.series:
+        logger.critical('Could not find revision %s', lower)
+        sys.exit(1)
+
+    # Prepare the lower fake-am range
+    lsc, lec = make_fake_commit_range(cmdargs.gitdir, lmbx.series[lower])
+    if lsc is None or lec is None:
+        logger.critical('---')
+        logger.critical('Could not create fake-am range for lower series v%s', lower)
+        os.unlink(mboxfile)
+        sys.exit(1)
+    # Prepare the upper fake-am range
+    usc, uec = make_fake_commit_range(cmdargs.gitdir, lmbx.series[upper])
+    if usc is None or uec is None:
+        logger.critical('---')
+        logger.critical('Could not create fake-am range for upper series v%s', upper)
+        os.unlink(mboxfile)
+        sys.exit(1)
+    logger.info('---')
+    logger.info('Success, you may now run:')
+    logger.info('    git range-diff %.12s..%.12s %.12s..%.12s', lsc, lec, usc, uec)
+