If fast-import was not run with --export-marks but we are crashing
the frontend application developer may still benefit from having
that information available to them.  We now include the marks table
as part of the crash report if --export-marks was not supplied on
the command line.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If annotated tags were created they exist in a different namespace
within the fast-import process' internal memory tables so we did
not export them in the inactive branch table.  Now they are written
out after the branches, in the order that they were defined by the
frontend process.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If the tree object we have asked for is deltafied in the packfile and
the delta did not apply correctly or was not able to be decompressed
from the packfile then we can get back NULL instead of the tree data.
This is (part of) the reason why read_sha1_file() can return NULL, so
we need to also handle it the same way.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Junio pointed out this part of fast-import wasn't very clear on
initial read, and it took some time for someone who was new to
fast-import's "dirty little tricks" to understand how this was
even working.  So a little bit of commentary in the proper place
may help future readers.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We now use the configured pack.compression and pack.depth values
within fast-import, as like builtin-pack-objects fast-import is
generating a packfile for consumption by the Git tools.

We use the same behavior as builtin-pack-objects does for these
options, allowing core.compression to supply the default value
for pack.compression.

The default setting for pack.depth within fast-import is still 10
as users will generally repack fast-import generated packfiles by
`repack -f`.  A large delta depth within the fast-import packfile
can significantly slow down such a later repack.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Without this change, each diagnostic could use an errno value
clobbered by the close or unlink in rollback_lock_file.
Signed-off-by: NJim Meyering <meyering@redhat.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

fast-import was relying on the fact that on most systems mmap() and
write() are synchronized by the filesystem's buffer cache.  We were
relying on the ability to mmap() 20 bytes beyond the current end
of the file, then later fill in those bytes with a future write()
call, then read them through the previously obtained mmap() address.

This isn't always true with some implementations of NFS, but it is
especially not true with our NO_MMAP=YesPlease build time option used
on some platforms.  If fast-import was built with NO_MMAP=YesPlease
we used the malloc()+pread() emulation and the subsequent write()
call does not update the trailing 20 bytes of a previously obtained
"mmap()" (aka malloc'd) address.

Under NO_MMAP that behavior causes unpack_entry() in sha1_file.c to
be unable to read an object header (or data) that has been unlucky
enough to be written to the packfile at a location such that it
is in the trailing 20 bytes of a window previously opened on that
same packfile.

This bug has gone unnoticed for a very long time as it is highly data
dependent.  Not only does the object have to be placed at the right
position, but it also needs to be positioned behind some other object
that has been accessed due to a branch cache invalidation.  In other
words the stars had to align just right, and if you did run into
this bug you probably should also have purchased a lottery ticket.

Fortunately the workaround is a lot easier than the bug explanation.

Before we allow unpack_entry() to read data from a pack window
that has also (possibly) been modified through write() we force
all existing windows on that packfile to be closed.  By closing
the windows we ensure that any new access via the emulated mmap()
will reread the packfile, updating to the current file content.

This comes at a slight performance degredation as we cannot reuse
previously cached windows when we update the packfile.  But it
is a fairly minor difference as the window closes happen at only
two points:

 - When the packfile is finalized and its .idx is generated:

   At this stage we are getting ready to update the refs and any
   data access into the packfile is going to be random, and is
   going after only the branch tips (to ensure they are valid).
   Our existing windows (if any) are not likely to be positioned
   at useful locations to access those final tip commits so we
   probably were closing them before anyway.

 - When the branch cache missed and we need to reload:

   At this point fast-import is getting change commands for the next
   commit and it needs to go re-read a tree object it previously
   had written out to the packfile.  What windows we had (if any)
   are not likely to cover the tree in question so we probably were
   closing them before anyway.

We do try to avoid unnecessarily closing windows in the second case
by checking to see if the packfile size has increased since the
last time we called unpack_entry() on that packfile.  If the size
has not changed then we have not written additional data, and any
existing window is still vaild.  This nicely handles the cases where
fast-import is going through a branch cache reload and needs to read
many trees at once.  During such an event we are not likely to be
updating the packfile so we do not cycle the windows between reads.

With this change in place t9301-fast-export.sh (which was broken
by c3b0dec5) finally works again.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

We also move the assignment of -1 to the lock file descriptor
up, so that rollback_lock_file() can be called safely after a
possible attempt to fclose(). This matches the contents of
the 'if' statement just above testing success of fdopen().
Signed-off-by: NBrandon Casey <casey@nrlssc.navy.mil>
Acked-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Remove remaining double close(2)'s.  i.e. close() before
commit_locked_index() or commit_lock_file().
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

I noticed some unchecked writes.  This fixes them.

* bundle.c (create_bundle): Die upon write failure.
* fast-import.c (keep_pack): Die upon write or close failure.
Signed-off-by: NJim Meyering <meyering@redhat.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

This updates send-pack and fast-import to use symbolic constants
for checking the return values from check_ref_format(), and also
futureproof the logic in lock_any_ref_for_update() to explicitly
name the case that is usually considered an error but is Ok for
this particular use.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The specialized pool allocator fast-import uses aligned objects on the
size of a pointer, which was not sufficient at least on Sparc.  Instead,
make the alignment for objects of type unitmax_t.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Brian Downing noticed fast-import can produce tree depths of up
to 6,035 objects and even deeper.  Long delta chains can create
very small packfiles but cause problems during repacking as git
needs to unpack each tree to count the reachable blobs.

What's happening here is the active branch cache isn't big enough.
We're swapping out the branch and thus recycling the tree information
(struct tree_content) back into the free pool.  When we later reload
the tree we set the delta_depth to 0 but we kept the tree we just
reloaded as a delta base.

So if the tree we reloaded was already at the maximum depth we
wouldn't know it and make the new tree a delta.  Multiply the
number of times the branch cache has to swap out the tree times
max_depth (10) and you get the maximum delta depth of a tree created
by fast-import.  In Brian's case above the active branch cache had
to swap the branch out 603/604 times during this import to produce
a tree with a delta depth of 6035.
Acked-by: NBrian Downing <bdowning@lavos.net>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Without this strbuf_detach(), it yields a double free later, the
command is in fact stashed, and this is not a memory leak.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

The arguments to the "Not a blob" die call in file_change_m were
transposed, so that the command was printed as the type, and the type
as the command.  Switch them around so that the error message comes
out correctly.
Signed-off-by: NJulian Phillips <julian@quantumfyre.co.uk>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

For that purpose, the ->buf is always initialized with a char * buf living
in the strbuf module. It is made a char * so that we can sloppily accept
things that perform: sb->buf[0] = '\0', and because you can't pass "" as an
initializer for ->buf without making gcc unhappy for very good reasons.

strbuf_init/_detach/_grow have been fixed to trust ->alloc and not ->buf
anymore.

as a consequence strbuf_detach is _mandatory_ to detach a buffer, copying
->buf isn't an option anymore, if ->buf is going to escape from the scope,
and eventually be free'd.

API changes:
  * strbuf_setlen now always works, so just make strbuf_reset a convenience
    macro.
  * strbuf_detatch takes a size_t* optional argument (meaning it can be
    NULL) to copy the buffer's len, as it was needed for this refactor to
    make the code more readable, and working like the callers.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

If the gain is not obvious in the diffstat, the resulting code is more
readable, _and_ in checkout-index/update-index we now reuse the same buffer
to unquote strings instead of always freeing/mallocing.

This also is more coherent with the next patch that reworks quoting
functions.

The quoting function is also made more efficient scanning for backslashes
and treating portions of strings without a backslash at once.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>

Add strbuf_remove, change strbuf_insert:
  As both are special cases of strbuf_splice, implement them as such.
  gcc is able to do the math and generate almost optimal code this way.

Add strbuf_swap:
  Exchange the values of its arguments.
  Use it in fast-import.c

Also fix spacing issues in strbuf.h
Signed-off-by: NPierre Habouzit <madcoder@debian.org>

Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Now that cmd_data acts on a strbuf, make last_object stashed buffer be a
strbuf as well. On new stash, don't free the last stashed buffer, rather
swap it with the one you will stash, this way, callers of store_object can
act on static strbufs, and at some point, fast-import won't allocate new
memory for objects buffers.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

read_line is now strbuf_getline, and is a first class citizen, it returns 0
when reading a line worked, EOF else.

The ->eof marker was used non-locally by fast-import.c, mimic the same
behaviour using a static int in "read_next_command", that now returns -1 on
EOF, and avoids to call strbuf_getline when it's in EOF state.

Also no longer automagically strbuf_release the buffer, it's counter
intuitive and breaks fast-import in a very subtle way.

Note: being at EOF implies that command_buf.len == 0.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

  * Add strbuf_rtrim to remove trailing spaces.
  * Add strbuf_insert to insert data at a given position.
  * Off-by one fix in strbuf_addf: strbuf_avail() does not counts the final
    \0 so the overflow test for snprintf is the strict comparison. This is
    not critical as the growth mechanism chosen will always allocate _more_
    memory than asked, so the second test will not fail. It's some kind of
    miracle though.
  * Add size extension hints for strbuf_init and strbuf_read. If 0, default
    applies, else:
      + initial buffer has the given size for strbuf_init.
      + first growth checks it has at least this size rather than the
        default 8192.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

  This patch features the use of strbuf_detach, and prevent the programmer
to mess with allocation directly. The code is as efficent as before, just
more concise and more straightforward.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

  The gory details are explained in strbuf.h. The change of semantics this
patch enforces is that the embeded buffer has always a '\0' character after
its last byte, to always make it a C-string. The offs-by-one changes are all
related to that very change.

  A strbuf can be used to store byte arrays, or as an extended string
library. The `buf' member can be passed to any C legacy string function,
because strbuf operations always ensure there is a terminating \0 at the end
of the buffer, not accounted in the `len' field of the structure.

  A strbuf can be used to generate a string/buffer whose final size is not
really known, and then "strbuf_detach" can be used to get the built buffer,
and keep the wrapping "strbuf" structure usable for further work again.

  Other interesting feature: strbuf_grow(sb, size) ensure that there is
enough allocated space in `sb' to put `size' new octets of data in the
buffer. It helps avoiding reallocating data for nothing when the problem the
strbuf helps to solve has a known typical size.
Signed-off-by: NPierre Habouzit <madcoder@debian.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

[sp: minor change to use fputs, thus reducing the patch size]
Signed-off-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

* skip_optional_lf() decl is old-style -- please say

	static skip_optional_lf(void)
        {
        	...
	}

* t9300 #14 fails, like this:

* expecting failure: git-fast-import <input
fatal: Branch name doesn't conform to GIT standards: .badbranchname
fast-import: dumping crash report to .git/fast_import_crash_14354
./test-lib.sh: line 143: 14354 Segmentation fault      git-fast-import <input

-- >8 --
Subject: [PATCH] fastimport: Fix re-use of va_list

The va_list is designed to be used only once. The current code
reuses va_list argument may cause segmentation fault.  Copy and
release the arguments to avoid this problem.

While we are at it, fix old-style function declaration of
skip_optional_lf().
Signed-off-by: NJunio C Hamano <gitster@pobox.com>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

When we crash the frontend developer (or end-user) may need to know
roughly around what part of the input stream we had a problem with
and aborted on.  Because line numbers aren't very useful in this
sort of application we instead just keep the last 100 commands in
a FIFO queue and print them as part of the crash report.

Currently one problem with this design is a commit that has
more than 100 modified files in it will flood the FIFO and any
context regarding branch/from/committer/mark/comments will be lost.
We really should save only the last few (10?) file changes for the
current commit, ensuring we have some prior higher level commands
in the FIFO when we crash on a file M/D/C/R command.

Another issue with this approach is the FIFO only includes the
commands, it does not include the commit messages.  Yet having a
commit message may be useful to help locate the relevant change in
the source material.  In practice I don't think this is going to be a
major concern as the frontend can always embed its own source change
set identifier as a comment (which will appear in the crash report)
and the commit message(s) for the most recent commits of any given
branch should be obtainable from the (packed) commit objects.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

As fast-import is quite strict about its input and die()'s anytime
something goes wrong it can be difficult for a frontend developer
to troubleshoot why fast-import rejected their input, or to even
determine what input command it rejected.

This change introduces a custom handler for Git's die() routine.
When we receive a die() for any reason (fast-import or a lower level
core Git routine we called) the error is first dumped onto stderr
and then a more extensive crash report file is prepared in GIT_DIR.
Finally we exit the process with status 128, just like the stock
builtin die handler.

An internal flag is set to prevent any further die()'s that may be
invoked during the crash report generator from causing us to enter
into an infinite loop.  We shouldn't die() from our crash report
handler, but just in case someone makes a future code change we are
prepared to gaurd against small mistakes turning into huge problems
for the end-user.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

The existing checkpoint command is very useful to force fast-import
to dump the branches out to disk so that standard Git tools can
access them and the objects they refer to.  However there was not a
way to know when fast-import had finished executing the checkpoint
and it was safe to read those refs.

The progress command can be used to make fast-import output any
message of the frontend's choosing to standard out.  The frontend
can scan for these messages using select() or poll() to monitor a
pipe connected to the standard output of fast-import.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

For the same reasons as the prior change we want to allow frontends
to omit the trailing LF that usually delimits commands.  In some
cases these just make the input stream more verbose looking than
it needs to be, and its just simpler for the frontend developer to
get started if our parser is slightly more lenient about where an
LF is required and where it isn't.

To make this optional LF feature work we now have to buffer up to one
line of input in command_buf.  This buffering can happen if we look
at the current input command but don't recognize it at this point
in the code.  In such a case we need to "unget" the entire line,
but we cannot depend upon the stdio library to let us do ungetc()
for that many characters at once.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

A few fast-import frontend developers have found it odd that we
require the LF following a `data` command, especially in the exact
byte count format.  Technically we don't need this LF to parse
the stream properly, but having it here does make the stream more
readable to humans.  We can easily make the LF optional by peeking
at the next byte available from the stream and pushing it back into
the buffer if its not LF.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Several frontend developers have asked that some form of stream
comments be permitted within a fast-import data stream.  This way
they can include information from their own frontend program about
where specific data was taken from in the source system, or about
a decision that their frontend may have made while creating the
fast-import data stream.

This change introduces comments in the Bourne-shell/Tcl/Perl style.
Lines starting with '#' are ignored, up to and including the LF.
Unlike the above mentioned three languages however we do not look for
and ignore leading whitespace.  This just simplifies the definition
of the comment format and the code that parses them.

To make comments work we had to stop using read_next_command() within
cmd_data() and directly invoke read_line() during the inline variant
of the function.  This is necessary to retain any lines of the
input data that might otherwise look like a comment to fast-import.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Instead of growing our buffer by hand during the inline variant of
cmd_data() we can save a few lines of code and just use the nifty
new ALLOC_GROW macro already available to us.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Michael Haggerty <mhagger@alum.mit.edu> noticed while debugging a
Git backend for cvs2svn that fast-import was barfing when he tried
to use "TAG_FIXUP" as a branch name for temporary work needed to
cleanup the tree prior to creating an annotated tag object.

The reason we were rejecting the branch name was check_ref_format()
returns -2 when there are less than 2 '/' characters in the input
name.  TAG_FIXUP has 0 '/' characters, but is technically just as
valid of a ref as HEAD and MERGE_HEAD, so we really should permit it
(and any other similar looking name) during import.

New test cases have been added to make sure we still detect very
wrong branch names (e.g. containing [ or starting with .) and yet
still permit reasonable names (e.g. TAG_FIXUP).
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Something probably assumed that HT indentation is 4 characters.
Signed-off-by: NAlex Riesen <raa.lkml@gmail.com>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

xmkstemp() performs error checking and prints a standard error message when
an error occur.
Signed-off-by: NLuiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Some source material (e.g. Subversion dump files) perform directory
renames by telling us the directory was copied, then deleted in the
same revision.  This makes it difficult for a frontend to convert
such data formats to a fast-import stream, as all the frontend has
on hand is "Copy a/ to b/; Delete a/" with no details about what
files are in a/, unless the frontend also kept track of all files.

The new 'C' subcommand within a commit allows the frontend to make a
recursive copy of one path to another path within the branch, without
needing to keep track of the individual file paths.  The metadata
copy is performed in memory efficiently, but is implemented as a
copy-immediately operation, rather than copy-on-write.

With this new 'C' subcommand frontends could obviously implement an
'R' (rename) on their own as a combination of 'C' and 'D' (delete),
but since we have already offered up 'R' in the past and it is a
trivial thing to keep implemented I'm not going to deprecate it.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

Some source material (e.g. Subversion dump files) perform directory
renames without telling us exactly which files in that subdirectory
were moved.  This makes it hard for a frontend to convert such data
formats to a fast-import stream, as all the frontend has on hand
is "Rename a/ to b/" with no details about what files are in a/,
unless the frontend also kept track of all files.

The new 'R' subcommand within a commit allows the frontend to
rename either a file or an entire subdirectory, without needing to
know the object's SHA-1 or the specific files contained within it.
The rename is performed as efficiently as possible internally,
making it cheaper than a 'D'/'M' pair for a file rename.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>