Hi David,
David Barr writes:
> Use the new cat-blob command for fast-import to extract
> blobs so that text-deltas may be applied.
I like this straightforward approach, and I like the name 'cat-blob'.
> The backchannel should only need to be configured when
> parsing v3 svn dump streams.
Maybe get the synopsis to say this as well?
> Based-on-patch-by: Ramkumar Ramachandra <artagnon@xxxxxxxxx>
> Based-on-patch-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
> Tested-by: David Barr <david.barr@xxxxxxxxxxxx>
> Signed-off-by: David Barr <david.barr@xxxxxxxxxxxx>
> ---
> contrib/svn-fe/svn-fe.txt | 6 +++-
> t/t9010-svn-fe.sh | 6 ++--
> vcs-svn/fast_export.c | 86 +++++++++++++++++++++++++++++++++++++++++++-
> 3 files changed, 92 insertions(+), 6 deletions(-)
>
> diff --git a/contrib/svn-fe/svn-fe.txt b/contrib/svn-fe/svn-fe.txt
> index 35f84bd..39ffa07 100644
> --- a/contrib/svn-fe/svn-fe.txt
> +++ b/contrib/svn-fe/svn-fe.txt
> @@ -7,7 +7,11 @@ svn-fe - convert an SVN "dumpfile" to a fast-import stream
>
> SYNOPSIS
> --------
> -svnadmin dump --incremental REPO | svn-fe [url] | git fast-import
> +[verse]
> +mkfifo backchannel &&
> +svnadmin dump --incremental REPO |
> + svn-fe [url] 3<backchannel |
> + git fast-import --cat-blob-fd=3 3>backchannel
See above.
> DESCRIPTION
> -----------
> diff --git a/t/t9010-svn-fe.sh b/t/t9010-svn-fe.sh
> index de976ed..d750c7a 100755
> --- a/t/t9010-svn-fe.sh
> +++ b/t/t9010-svn-fe.sh
> @@ -34,10 +34,10 @@ test_dump () {
> svnadmin load "$label-svn" < "$TEST_DIRECTORY/$dump" &&
> svn_cmd export "file://$PWD/$label-svn" "$label-svnco" &&
> git init "$label-git" &&
> - test-svn-fe "$TEST_DIRECTORY/$dump" >"$label.fe" &&
> (
> - cd "$label-git" &&
> - git fast-import < ../"$label.fe"
> + cd "$label-git" && mkfifo backchannel && \
> + test-svn-fe "$TEST_DIRECTORY/$dump" 3< backchannel | \
> + git fast-import --cat-blob-fd=3 3> backchannel
> ) &&
> (
> cd "$label-svnco" &&
Ok.
> diff --git a/vcs-svn/fast_export.c b/vcs-svn/fast_export.c
> index b017dfb..812563d 100644
> --- a/vcs-svn/fast_export.c
> +++ b/vcs-svn/fast_export.c
> @@ -8,10 +8,17 @@
> #include "line_buffer.h"
> #include "repo_tree.h"
> #include "string_pool.h"
> +#include "svndiff.h"
>
> #define MAX_GITSVN_LINE_LEN 4096
> +#define REPORT_FILENO 3
> +
> +#define SHA1_HEX_LENGTH 40
>
> static uint32_t first_commit_done;
> +static struct line_buffer preimage = LINE_BUFFER_INIT;
> +static struct line_buffer postimage = LINE_BUFFER_INIT;
> +static struct line_buffer backchannel = LINE_BUFFER_INIT;
Elegant :)
> void fast_export_delete(uint32_t depth, uint32_t *path)
> {
> @@ -63,16 +70,91 @@ void fast_export_commit(uint32_t revision, uint32_t author, char *log,
> printf("progress Imported commit %"PRIu32".\n\n", revision);
> }
>
> +static int fast_export_save_blob(FILE *out)
> +{
> + size_t len;
> + char *header;
> + char *end;
> + char *tail;
> +
> + if (!backchannel.infile)
> + backchannel.infile = fdopen(REPORT_FILENO, "r");
> + if (!backchannel.infile)
> + return error("Could not open backchannel fd: %d", REPORT_FILENO);
REPORT_FILENO = 3 is hard-coded. Is this intended? Maybe a
command-line option to specify the fd?
> + header = buffer_read_line(&backchannel);
> + if (header == NULL)
> + return 1;
Note to self: This prints the error "Failed to retrieve blob for delta
application" in the caller.
> + end = strchr(header, '\0');
> + if (end - header > 7 && !strcmp(end - 7, "missing"))
> + return error("cat-blob reports missing blob: %s", header);
> + if (end - header < SHA1_HEX_LENGTH)
> + return error("cat-blob header too short for SHA1: %s", header);
> + if (strncmp(header + SHA1_HEX_LENGTH, " blob ", 6))
> + return error("cat-blob header has wrong object type: %s", header);
> + len = strtoumax(header + SHA1_HEX_LENGTH + 6, &end, 10);
> + if (end == header + SHA1_HEX_LENGTH + 6)
> + return error("cat-blob header did not contain length: %s", header);
> + if (*end)
> + return error("cat-blob header contained garbage after length: %s", header);
> + buffer_copy_bytes(&backchannel, out, len);
> + tail = buffer_read_line(&backchannel);
> + if (!tail)
> + return 1;
Could you clarify when exactly will this happen?
> + if (*tail)
> + return error("cat-blob trailing line contained garbage: %s", tail);
> + return 0;
> +}
> +
> void fast_export_blob(uint32_t mode, uint32_t mark, uint32_t len,
> uint32_t delta, uint32_t srcMark, uint32_t srcMode,
> struct line_buffer *input)
> {
Note to reviewers: The function looks like this in `master`:
void fast_export_blob(uint32_t mode, uint32_t mark, uint32_t len)
New parameters intrduced in the svn-fe3 series: srcMark, srcMode,
delta, input.
> + long preimage_len = 0;
> +
> + if (delta) {
> + if (!preimage.infile)
> + preimage.infile = tmpfile();
Didn't you later decide against this and use one tmpfile instead? In
this case, the temporary file will be automatically deleted when
`preimage.infile` goes out of scope.
> + if (!preimage.infile)
> + die("Unable to open temp file for blob retrieval");
> + if (srcMark) {
> + printf("cat-blob :%"PRIu32"\n", srcMark);
> + fflush(stdout);
> + if (srcMode == REPO_MODE_LNK)
> + fwrite("link ", 1, 5, preimage.infile);
Special handling for symbolic links. Perhaps you should mention it in
a comment here?
> + if (fast_export_save_blob(preimage.infile))
> + die("Failed to retrieve blob for delta application");
> + }
> + preimage_len = ftell(preimage.infile);
> + fseek(preimage.infile, 0, SEEK_SET);
> + if (!postimage.infile)
> + postimage.infile = tmpfile();
One tmpfile?
> + if (!postimage.infile)
> + die("Unable to open temp file for blob application");
> + svndiff0_apply(input, len, &preimage, postimage.infile);
> + len = ftell(postimage.infile);
Since you already have a preimage_len, perhaps name this postimage_len
to avoid confusion?
> + fseek(postimage.infile, 0, SEEK_SET);
> + }
> +
> if (mode == REPO_MODE_LNK) {
> /* svn symlink blobs start with "link " */
> - buffer_skip_bytes(input, 5);
> + if (delta)
> + buffer_skip_bytes(&postimage, 5);
> + else
> + buffer_skip_bytes(input, 5);
> len -= 5;
> }
> printf("blob\nmark :%"PRIu32"\ndata %"PRIu32"\n", mark, len);
> - buffer_copy_bytes(input, stdout, len);
> + if (!delta)
> + buffer_copy_bytes(input, stdout, len);
> + else
> + buffer_copy_bytes(&postimage, stdout, len);
> fputc('\n', stdout);
I should have asked this a long time ago: why the extra newline?
> +
> + if (preimage.infile) {
> + fseek(preimage.infile, 0, SEEK_SET);
> + }
> +
> + if (postimage.infile) {
> + fseek(postimage.infile, 0, SEEK_SET);
> + }
Style nits: The extra braces around the `if` statement are unnecessary.
Overall, pleasant read. Thanks for taking this forward.
-- Ram
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