prefixcmp() and suffixcmp() share the common "cmp" suffix that
typically are used to name functions that can be used for ordering,
but they can't, because they are not antisymmetric:
prefixcmp("foo", "foobar") < 0
prefixcmp("foobar", "foo") == 0
We in fact do not use these functions for ordering. Replace them
with functions that just check for equality.
Add starts_with() and end_with() that will be used to replace
prefixcmp() and suffixcmp(), respectively, as the first step. These
are named after corresponding functions/methods in programming
languages, like Java, Python and Ruby.
In vcs-svn/fast_export.c, there was already an ends_with() function
that did the same thing. Let's use the new one instead while at it.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Search for a note attached to the ref to update and read it's
'Revision-number:'-line. Start import from the next svn revision.
If there is no next revision in the svn repo, svnrdump terminates with
a message on stderr an non-zero return value. This looks a little
weird, but there is no other way to know whether there is a new
revision in the svn repo.
On the start of an incremental import, the parent of the first commit
in the fast-import stream is set to the branch name to update. All
following commits specify their parent by a mark number. Previous mark
files are currently not reused.
Signed-off-by: Florian Achleitner <florian.achleitner.2.6.31@gmail.com>
Acked-by: David Michael Barr <b@rr-dav.id.au>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
To provide metadata from svn dumps for further processing, e.g.
branch detection, attach a note to each imported commit that stores
additional information. The notes are currently hard-coded in
refs/notes/svn/revs. Currently the following lines from the svn dump
are directly accumulated in the note. This can be refined as needed.
- "Revision-number"
- "Node-path"
- "Node-kind"
- "Node-action"
- "Node-copyfrom-path"
- "Node-copyfrom-rev"
Signed-off-by: Florian Achleitner <florian.achleitner.2.6.31@gmail.com>
Acked-by: David Michael Barr <b@rr-dav.id.au>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
fast_export lacked a method to writes notes to fast-import stream.
Add two new functions fast_export_note which is similar to
fast_export_modify. And also add fast_export_buf_to_data to be able to
write inline blobs that don't come from a line_buffer or from delta
application.
To be used like this:
fast_export_begin_commit("refs/notes/somenotes", ...)
fast_export_note("refs/heads/master", "inline")
fast_export_buf_to_data(&data)
or maybe
fast_export_note("refs/heads/master", sha1)
Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Florian Achleitner <florian.achleitner.2.6.31@gmail.com>
Acked-by: David Michael Barr <b@rr-dav.id.au>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The reference to update by the fast-import stream is hard-coded. When
fetching from a remote the remote-helper shall update refs in a
private namespace, i.e. a private subdir of refs/. This namespace is
defined by the 'refspec' capability, that the remote-helper advertises
as a reply to the 'capabilities' command.
Extend svndump and fast-export to allow passing the target ref.
Update svn-fe to be compatible.
Signed-off-by: Florian Achleitner <florian.achleitner.2.6.31@gmail.com>
Acked-by: David Michael Barr <b@rr-dav.id.au>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The existing function only allows reading from a filename or from
stdin. Allow passing of a FD and an additional FD for the back report
pipe. This allows us to retrieve the name of the pipe in the caller.
Signed-off-by: Florian Achleitner <florian.achleitner.2.6.31@gmail.com>
Acked-by: David Michael Barr <b@rr-dav.id.au>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Currently the vcs-svn/ library only pays attention to the presence of
the Prop-Content-Length field and doesn't care about its value, but
some day we might care about the value. Parse it as an off_t instead
of arbitrarily limiting to 32 bits for intuitiveness.
So now you can import from a dump with more than 2 GiB of properties
for a node. In practice that isn't likely to happen often, and this
is mostly meant as a cleanup.
Based-on-patch-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
All callers pass a nonnegative delta_len, so the code is already safe.
Add an assertion to ensure that remains so and add a cast to keep
clang and gcc -Wsign-compare from worrying.
Reported-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
The preceding code checks that view->max_off is nonnegative and
(off + width) fits in an off_t, so this code is already safe.
Signed-off-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
These are already safe because both sides of the comparison are
nonnegative.
This would normally not be important because Git is not -Wsign-compare
clean anyway, but we like to keep the vcs-svn/ lib to a higher
standard for convenience using it in other projects.
Signed-off-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
memmem is a GNU extension.
Avoiding it makes the code clearer and makes it easier for projects
that don't share git's compat/ code, such as the standalone
svn-dump-fast-export project, to reuse the vcs-svn/ library.
Signed-off-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Since the length of t is already known, we can simplify a little by
using memcmp() instead of strncmp() to carry out a prefix comparison.
All nearby code already does this.
Noticed in the standalone svn-dump-fast-export project which has not
needed to implement prefixcmp() yet.
Signed-off-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Currently the cleanup code looks like this:
free resources
return 0;
error_out:
free resources
return -1;
Avoid duplicating the "free resources" part by keeping the return
value in a variable and sharing code between the success and
exceptional case:
ret = 0;
out:
free resources
return ret;
Noticed in the svn-dump-fast-export project, where using the error()
macro in void context produces a warning.
Signed-off-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Without this change, clang complains:
vcs-svn/svndiff.c:298:3: warning: Assigned value is garbage or undefined
off_t pre_off = pre_off; /* stupid GCC... */
^ ~~~~~~~
This code uses an old and common idiom for suppressing an
"uninitialized variable" warning, and clang is wrong to warn about it.
The idiom tells the compiler to leave the variable uninitialized,
which saves a few bytes of code size, and, more importantly, allows
valgrind to check at runtime that the variable is properly initialized
by the time it is used.
But MSVC and clang do not know that idiom, so let's avoid it in
vcs-svn/ code.
Initialize pre_off to -1, a recognizably meaningless value, to allow
future code changes that cause pre_off to be used before it is
initialized to be caught early.
Signed-off-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Since v1.7.5~42^2~6 (vcs-svn: remove buffer_read_string)
buffer_reset() does nothing thus fast_export_reset() also.
Signed-off-by: David Barr <davidbarr@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
The error handling routines add a newline. Remove
the duplicate ones in error messages.
Signed-off-by: Pete Wyckoff <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On 32-bit architectures with 64-bit file offsets, gcc 4.3 and earlier
produce the following warning:
CC vcs-svn/sliding_window.o
vcs-svn/sliding_window.c: In function `check_overflow':
vcs-svn/sliding_window.c:36: warning: comparison is always false \
due to limited range of data type
The warning appears even when gcc is run without any warning flags
(this is gcc bug 12963). In later versions the same warning can be
reproduced with -Wtype-limits, which is implied by -Wextra.
On 64-bit architectures it really is possible for a size_t not to be
representable as an off_t so the check this is warning about is not
actually redundant. But even false positives are distracting. Avoid
the warning by making the "len" argument to check_overflow a
uintmax_t; no functional change intended.
Reported-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is no reason in principle that an svn-format dump would not be
able to represent a file whose length does not fit in a 32-bit
integer. Use off_t consistently to represent file lengths (in place
of using uint32_t in some contexts) so we can handle that.
Most svn-fe code is already ready to do that without this patch and
passes values of type off_t around. The type mismatch from stragglers
was noticed with gcc -Wtype-limits.
While at it, tighten the parsing of the Text-content-length field to
make sure it is a number and does not overflow, and tighten other
overflow checks as that value is passed around and manipulated.
Inspired-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Code using the argument names a and b just doesn't look right (not
sure why!). Use more explicit names "offset" and "len" to make their
type and meaning clearer.
Also rename check_overflow() to check_offset_overflow() to clarify
that we are making sure that "len" bytes beyond "offset" still fits
the type to represent an offset.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
On 32-bit architectures with 64-bit file offsets, gcc 4.3 and earlier
produce the following warning:
CC vcs-svn/sliding_window.o
vcs-svn/sliding_window.c: In function `check_overflow':
vcs-svn/sliding_window.c:36: warning: comparison is always false \
due to limited range of data type
The warning appears even when gcc is run without any warning flags
(PR12963). In later versions it can be reproduced with -Wtype-limits,
which is implied by -Wextra.
On 64-bit architectures it really is possible for a size_t not to be
representable as an off_t so the check being warned about is not
actually redundant. But even false positives are distracting. Avoid
the warning by making the "len" argument to check_overflow a
uintmax_t; no functional change intended.
Reported-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
There is no reason in principle that an svn-format dump would not
be able to represent a file whose length does not fit in a 32-bit
integer. Use off_t consistently (instead of uint32_t) to represent
file lengths so we can handle that.
Most of our code is already ready to do that without this patch and
already passes values of type off_t around. The type mismatch due to
stragglers was noticed with gcc -Wtype-limits.
Inspired-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
The canonical interpretation of a range a,b is as an interval [a,b),
not [a,a+b), so this function taking argument names a and b feels
unnatural. Use more explicit names "offset" and "len" to make the
arguments' type and function clearer.
While at it, rename the function to convey that we are making sure
the sum of this offset and length do not overflow an off_t, not a
size_t.
[jn: split out from a patch from Ramsay Jones, then improved with
advice from Thomas Rast, Dmitry Ivankov, and David Barr]
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Improved-by: Dmitry Ivankov <divanorama@gmail.com>
Curiously, pre_len given to read_length() does not trigger the same warning
even though the code structure is the same. Most likely this is because
read_offset() is used only once and inlining it will make gcc realize that
it has a chance to do more flow analysis. Alas, the analysis is flawed, so
it does not help X-<.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This simplifies svn-fe a great deal and fulfills a longstanding wish:
support for dumps with deltas in them, and incremental imports.
The cost is that commandline usage of the svn-fe tool becomes a little
more complicated since it no longer keeps state itself but instead reads
blobs back from fast-import in order to copy them between revisions and
apply deltas to them.
Also removes a couple of custom data structures and replaces them with
strbufs like other parts of Git.
* 'svn-fe' of git://repo.or.cz/git/jrn: (32 commits)
vcs-svn: reset first_commit_done in fast_export_init
vcs-svn: do not initialize report_buffer twice
vcs-svn: avoid hangs from corrupt deltas
vcs-svn: guard against overflow when computing preimage length
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: implement text-delta handling
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
vcs-svn: avoid using ls command twice
...
Conflicts:
Makefile
contrib/svn-fe/svn-fe.txt
Change direct and indirect assignments of the bitwise negation of 0 to
uint32_t variables to have a "U" suffix. I.e. ~0U instead of ~0. This
eliminates warnings under Sun Studio 12 Update 1:
"vcs-svn/string_pool.c", line 11: warning: initializer will be sign-extended: -1 (E_INIT_SIGN_EXTEND)
"vcs-svn/string_pool.c", line 81: warning: initializer will be sign-extended: -1 (E_INIT_SIGN_EXTEND)
"vcs-svn/repo_tree.c", line 112: warning: initializer will be sign-extended: -1 (E_INIT_SIGN_EXTEND)
"vcs-svn/repo_tree.c", line 112: warning: initializer will be sign-extended: -1 (E_INIT_SIGN_EXTEND)
"test-treap.c", line 34: warning: initializer will be sign-extended: -1 (E_INIT_SIGN_EXTEND)
The semantics are still the same as demonstrated by this program:
$ cat test.c && make test && ./test
#include <stdio.h>
#include <stdint.h>
int main(void)
{
uint32_t foo = ~0;
uint32_t bar = ~0U;
printf("foo = <%u> bar = <%u>\n", foo, bar);
return 0;
}
cc test.c -o test
"test.c", line 5: warning: initializer will be sign-extended: -1
foo = <4294967295> bar = <4294967295>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
first_commit_done has zero as a default value, but it
is not reset back to zero in fast_export_init.
Reset it back to zero so that each export will have
proper initial state.
Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
When importing from a dump with deltas, first fast_export_init calls
buffer_fdinit, and then init_report_buffer calls fdopen once again
when processing the first delta. The second initialization is
redundant and leaks a FILE *.
Remove the redundant on-demand initialization to fix this.
Initializing directly in fast_export_init is simpler and lets the
caller pass an int specifying which fd to use instead of hard-coding
REPORT_FILENO.
Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
A corrupt Subversion-format delta can request reads past the end of
the preimage. Set sliding_view::max_off so such corruption is caught
when it appears rather than blocking in an impossible-to-fulfill
read() when input is coming from a socket or pipe.
Inspired-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed integer overflow produces undefined behavior in C and off_t is
a signed type. For predictable behavior, add some checks to protect
in advance against overflow.
On 32-bit systems ftell as called by buffer_tmpfile_prepare_to_read
is likely to fail with EOVERFLOW when reading the corresponding
postimage, and this patch does not fix that. So it's more of a
futureproofing measure than a complete fix.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Introduce a "max_off" field in struct sliding_view, roughly
representing a maximum number of bytes that can be read from "file".
If it is set to a nonnegative integer, a call to move_window()
attempting to put the right endpoint beyond that offset will return
an error instead.
The idea is to use this when applying Subversion-format deltas to
prevent reads past the end of the preimage (which has known length).
Without such a check, corrupt deltas would cause svn-fe to block
indefinitely when data in the input pipe is exhausted.
Inspired-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Handle input in Subversion's dumpfile format, version 3. This is the
format produced by "svnrdump dump" and "svnadmin dump --deltas", and
the main difference between v3 dumpfiles and the dumpfiles already
handled is that these can include nodes whose properties and text are
expressed relative to some other node.
To handle such nodes, we find which node the text and properties are
based on, handle its property changes, use the cat-blob command to
request the basis blob from the fast-import backend, use the
svndiff0_apply() helper to apply the text delta on the fly, writing
output to a temporary file, and then measure that postimage file's
length and write its content to the fast-import stream.
The temporary postimage file is shared between delta-using nodes to
avoid some file system overhead.
The svn-fe interface needs to be more complicated to accomodate the
backward flow of information from the fast-import backend to svn-fe.
The backflow fd is not needed when parsing streams without deltas,
though, so existing scripts using svn-fe on v2 dumps should
continue to work.
NEEDSWORK: generalize interface so caller sets the backflow fd, close
temporary file before exiting
Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
* db/delta-applier:
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
* db/svn-fe-code-purge:
vcs-svn: drop obj_pool
vcs-svn: drop treap
vcs-svn: drop string_pool
vcs-svn: pass paths through to fast-import
Conflicts:
vcs-svn/fast_export.c
vcs-svn/fast_export.h
vcs-svn/repo_tree.c
vcs-svn/repo_tree.h
vcs-svn/string_pool.c
vcs-svn/svndump.c
vcs-svn/trp.txt
This teaches svn-fe to incrementally import into an existing
repository (at last!) at the expense of less convenient UI. Think of
it as growing pains. This opens the door to many excellent things,
and it would be a bad idea to discourage people from building on it
for much longer.
* db/vcs-svn-incremental:
vcs-svn: avoid using ls command twice
vcs-svn: use mark from previous import for parent commit
vcs-svn: handle filenames with dq correctly
vcs-svn: quote paths correctly for ls command
vcs-svn: eliminate repo_tree structure
vcs-svn: add a comment before each commit
vcs-svn: save marks for imported commits
vcs-svn: use higher mark numbers for blobs
vcs-svn: set up channel to read fast-import cat-blob response
Conflicts:
t/t9010-svn-fe.sh
vcs-svn/fast_export.c
vcs-svn/fast_export.h
vcs-svn/repo_tree.c
vcs-svn/svndump.c
* rj/sparse:
sparse: Fix some "symbol not declared" warnings
sparse: Fix errors due to missing target-specific variables
sparse: Fix an "symbol 'merge_file' not decared" warning
sparse: Fix an "symbol 'format_subject' not declared" warning
sparse: Fix some "Using plain integer as NULL pointer" warnings
sparse: Fix an "symbol 'cmd_index_pack' not declared" warning
Makefile: Use cgcc rather than sparse in the check target
In particular, sparse issues the "symbol 'a_symbol' was not declared.
Should it be static?" warnings for the following symbols:
attr.c:468:12: 'git_etc_gitattributes'
attr.c:476:5: 'git_attr_system'
vcs-svn/svndump.c:282:6: 'svndump_read'
vcs-svn/svndump.c:417:5: 'svndump_init'
vcs-svn/svndump.c:432:6: 'svndump_deinit'
vcs-svn/svndump.c:445:6: 'svndump_reset'
The symbols in attr.c only require file scope, so we add the static
modifier to their declaration.
The symbols in vcs-svn/svndump.c are external symbols, and they
already have extern declarations in the "svndump.h" header file,
so we simply include the header in svndump.c.
Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
I found that some doubled words had snuck back into projects from which
I'd already removed them, so now there's a "syntax-check" makefile rule in
gnulib to help prevent recurrence.
Running the command below spotted a few in git, too:
git ls-files | xargs perl -0777 -n \
-e 'while (/\b(then?|[iao]n|i[fst]|but|f?or|at|and|[dt])\s+\1\b/gims)' \
-e '{$n=($` =~ tr/\n/\n/ + 1); ($v=$&)=~s/\n/\\n/g;' \
-e 'print "$ARGV:$n:$v\n"}'
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* 'svn-fe' of git://repo.or.cz/git/jrn:
tests: kill backgrounded processes more robustly
vcs-svn: a void function shouldn't try to return something
tests: make sure input to sed is newline terminated
vcs-svn: add missing cast to printf argument
As v1.7.4-rc0~184 (2010-10-04) and C99 §6.8.6.4.1 remind us, standard
C does not permit returning an expression of type void, even for a
tail call.
Noticed with gcc -pedantic:
vcs-svn/svndump.c: In function 'handle_node':
vcs-svn/svndump.c:213:3: warning: ISO C forbids 'return' with expression,
in function returning void [-pedantic]
[jn: with simplified log message]
Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
gcc -m32 correctly warns:
vcs-svn/fast_export.c: In function 'fast_export_commit':
vcs-svn/fast_export.c:54:2: warning: format '%llu' expects
argument of type 'long long unsigned int', but argument 2
has type 'unsigned int' [-Wformat]
Fix it.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The copyfrom_source instruction appends data from the preimage buffer
to the end of output. Its arguments are a length and an offset
relative to the beginning of the source view.
With this change, the delta applier is able to reproduce all 5,636,613
blobs in the early history of the ASF repository. Tested with
mkfifo backflow
svn-fe <svn-asf-public-r0:940166 3<backflow |
git fast-import --cat-blob-fd=3 3>backflow
with svn-asf-public-r0:940166 produced by whatever version of
Subversion the dumps in /dump/ on svn.apache.org use (presumably
1.6.something).
Improved-by: Ramkumar Ramachandra <artagnon@gmail.com>
Improved-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Ramkumar Ramachandra <artagnon@gmail.com>
The copyfrom_target instruction copies appends data that is already
present in the current output view to the end of output. (The offset
argument is relative to the beginning of output produced in the
current window.)
The region copied is allowed to run past the end of the existing
output. To support that case, copy one character at a time rather
than calling memcpy or memmove. This allows copyfrom_target to be
used once to repeat a string many times. For example:
COPYFROM_DATA 2
COPYFROM_OUTPUT 10, 0
DATA "ab"
would produce the output "ababababababababababab".
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Ramkumar Ramachandra <artagnon@gmail.com>
By constraining the format of deltas, we can more easily detect
corruption and other breakage.
Requiring deltas not to provide unconsumed data also opens the
possibility of ignoring the declared amount of novel data and simply
streaming the data as needed to fulfill copyfrom_data requests.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Ramkumar Ramachandra <artagnon@gmail.com>
The copyfrom_data instruction copies a few bytes verbatim from the
novel text section of a window to the postimage.
[jn: with memory leak fix from David]
Improved-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Ramkumar Ramachandra <artagnon@gmail.com>
Buffer the instruction section upon encountering it for later
interpretation.
An alternative design would involve parsing the instructions
at this point and buffering them in some processed form. Using
the unprocessed form is simpler.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Ramkumar Ramachandra <artagnon@gmail.com>
Each window of an svndiff0-format delta includes a section for novel
text to be copied to the postimage (in the order it appears in the
window, possibly interspersed with other data).
Slurp in this data when encountering it. It is not actually necessary
to do so --- it would be just as easy to copy from delta to output
as part of interpreting the relevant instructions --- but this way,
the code that interprets svndiff0 instructions can proceed very
quickly because it does not require I/O.
Subversion's svndiff0 parser rejects deltas that do not consume all
the novel text that was provided. Omit that check for now so we can
test the new functionality right away, rather than waiting to learn
instructions that consume data.
Do check for truncated data sections. Subversion's parser rejects
deltas that end in the middle of a declared novel-text section, so it
should be safe for us to reject them, too.
Improved-by: Ramkumar Ramachandra <artagnon@gmail.com>
Improved-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Ramkumar Ramachandra <artagnon@gmail.com>
The source view offset heading each svndiff0 window represents a
number of bytes past the beginning of the preimage. Together with the
source view length, it dictates to the delta applier what portion of
the preimage instructions will refer to. Read that portion right away
using the sliding window code.
Maybe some day we will use mmap to read data more lazily.
Subversion's implementation tolerates source view offsets pointing
past the end of the preimage file but we do not, for simplicity.
This does not teach the delta applier to read instructions or copy
data from the source view. Deltas that could produce nonempty output
will still be rejected.
Improved-by: Ramkumar Ramachandra <artagnon@gmail.com>
Improved-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Acked-by: Ramkumar Ramachandra <artagnon@gmail.com>
Each window in a subversion delta (svndiff0-format file) starts with a
window header, consisting of five integers with variable-length
representation:
source view offset
source view length
output length
instructions length
auxiliary data length
Parse it. The result is not usable for deltas with nonempty postimage
yet; in fact, this only adds support for deltas without any
instructions or auxiliary data. This is a good place to stop, though,
since that little support lets us add some simple passing tests
concerning error handling to the test suite.
Improved-by: Ramkumar Ramachandra <artagnon@gmail.com>
Improved-by: David Barr <david.barr@cordelta.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
