Commit Graph

6 Commits

Author SHA1 Message Date
Jonathan Nieder
a8d3d26545 Merge branch 'db/delta-applier' into svn-fe
* db/delta-applier:
  vcs-svn: cap number of bytes read from sliding view
  test-svn-fe: split off "test-svn-fe -d" into a separate function
  vcs-svn: let deltas use data from preimage
  vcs-svn: let deltas use data from postimage
  vcs-svn: verify that deltas consume all inline data
  vcs-svn: implement copyfrom_data delta instruction
  vcs-svn: read instructions from deltas
  vcs-svn: read inline data from deltas
  vcs-svn: read the preimage when applying deltas
  vcs-svn: parse svndiff0 window header
  vcs-svn: skeleton of an svn delta parser
  vcs-svn: make buffer_read_binary API more convenient
  vcs-svn: learn to maintain a sliding view of a file
  Makefile: list one vcs-svn/xdiff object or header per line

Conflicts:
	Makefile
	vcs-svn/LICENSE
2011-06-15 02:17:51 -05:00
Jonathan Nieder
9d2f5ddfe5 vcs-svn: learn to maintain a sliding view of a file
Each section of a Subversion-format delta only requires examining (and
keeping in random-access memory) a small portion of the preimage.  At
any moment, this portion starts at a certain file offset and has a
well-defined length, and as the delta is applied, the portion advances
from the beginning to the end of the preimage.  Add a move_window
function to keep track of this view into the preimage.

You can use it like this:

	buffer_init(f, NULL);
	struct sliding_view window = SLIDING_VIEW_INIT(f);
	move_window(&window, 3, 7);	/* (1) */
	move_window(&window, 5, 5);	/* (2) */
	move_window(&window, 12, 2);	/* (3) */
	strbuf_release(&window.buf);
	buffer_deinit(f);

The data structure is called sliding_view instead of _window to
prevent confusion with svndiff0 Windows.

In this example, (1) reads 10 bytes and discards the first 3;
(2) discards the first 2, which are not needed any more; and (3) skips
2 bytes and reads 2 new bytes to work with.

When move_window returns, the file position indicator is at position
window->off + window->width and the data from positions window->off to
the current file position are stored in window->buf.

This function performs only sequential access from the input file and
never seeks, so it can be safely used on pipes and sockets.

On end-of-file, move_window silently reads less than the caller
requested.  On other errors, it prints a message and returns -1.

Helped-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2011-03-27 20:23:32 -05:00
David Barr
5db348dbd5 vcs-svn: drop treap
This reverts commit 951f316470
(Add treap implementation, 2010-08-09).  The string_pool was
trp.h's last user.

Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2011-03-22 18:34:44 -05:00
David Barr
21746aa34f SVN dump parser
svndump parses data that is in SVN dumpfile format produced by
`svnadmin dump` with the help of line_buffer and uses repo_tree and
fast_export to emit a git fast-import stream.

Based roughly on com.hydrografix.svndump 0.92 from the SvnToCCase
project at <http://svn2cc.sarovar.org/>, by Stefan Hegny and
others.

[rr: allow input from files other than stdin]
[jn: with test, more error reporting]

Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-14 19:35:38 -07:00
Jason Evans
951f316470 Add treap implementation
Provide macros to generate a type-specific treap implementation and
various functions to operate on it. It uses obj_pool.h to store memory
nodes in a treap.  Previously committed nodes are never removed from
the pool; after any *_commit operation, it is assumed (correctly, in
the case of svn-fast-export) that someone else must care about them.

Treaps provide a memory-efficient binary search tree structure.
Insertion/deletion/search are about as about as fast in the average
case as red-black trees and the chances of worst-case behavior are
vanishingly small, thanks to (pseudo-)randomness.  The bad worst-case
behavior is a small price to pay, given that treaps are much simpler
to implement.

>From http://www.canonware.com/download/trp/trp_hash/trp.h

[db: Altered to reference nodes by offset from a common base pointer]
[db: Bob Jenkins' hashing implementation dropped for Knuth's]
[db: Methods unnecessary for search and insert dropped]
[rr: Squelched compiler warnings]
[db: Added support for immutable treap nodes]
[jn: Reintroduced treap_nsearch(); with tests]

Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-14 19:35:37 -07:00
Jonathan Nieder
3f527372d9 Introduce vcs-svn lib
Teach the build system to build a separate library for the
upcoming subversion interop support.

The resulting vcs-svn/lib.a does not contain any code, nor is
it built during a normal build.  This is just scaffolding for
later changes.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-14 19:35:37 -07:00