From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 3 Aug 2015 18:01:23 +0000 (-0700)
Subject: Merge branch 'mh/fast-import-get-mark'
X-Git-Tag: v2.6.0-rc0~98
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/c0d503433f99916f727b8ce75be957ee650a4095?hp=-c

Merge branch 'mh/fast-import-get-mark'

"git fast-import" learned to respond to the get-mark command via
its cat-blob-fd interface.

* mh/fast-import-get-mark:
fast-import: add a get-mark command
---

c0d503433f99916f727b8ce75be957ee650a4095
diff --combined Documentation/git-fast-import.txt
index fd32895255,c19b9ce557..66910aa2fa
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@@ -42,19 -42,19 +42,19 @@@ OPTION
  --quiet::
  	Disable all non-fatal output, making fast-import silent when it
  	is successful.  This option disables the output shown by
 -	\--stats.
 +	--stats.
  
  --stats::
  	Display some basic statistics about the objects fast-import has
  	created, the packfiles they were stored into, and the
  	memory used by fast-import during this run.  Showing this output
 -	is currently the default, but can be disabled with \--quiet.
 +	is currently the default, but can be disabled with --quiet.
  
  Options for Frontends
  ~~~~~~~~~~~~~~~~~~~~~
  
  --cat-blob-fd=<fd>::
- 	Write responses to `cat-blob` and `ls` queries to the
+ 	Write responses to `get-mark`, `cat-blob`, and `ls` queries to the
  	file descriptor <fd> instead of `stdout`.  Allows `progress`
  	output intended for the end-user to be separated from other
  	output.
@@@ -81,12 -81,12 +81,12 @@@ Locations of Marks File
  	have been completed, or to save the marks table across
  	incremental runs.  As <file> is only opened and truncated
  	at checkpoint (or completion) the same path can also be
 -	safely given to \--import-marks.
 +	safely given to --import-marks.
  
  --import-marks=<file>::
  	Before processing any input, load the marks specified in
  	<file>.  The input file must exist, must be readable, and
 -	must use the same format as produced by \--export-marks.
 +	must use the same format as produced by --export-marks.
  	Multiple options may be supplied to import more than one
  	set of marks.  If a mark is defined to different values,
  	the last file wins.
@@@ -179,8 -179,8 +179,8 @@@ fast-forward update, fast-import will s
  prints a warning message.  fast-import will always attempt to update all
  branch refs, and does not stop on the first failure.
  
 -Branch updates can be forced with \--force, but it's recommended that
 -this only be used on an otherwise quiet repository.  Using \--force
 +Branch updates can be forced with --force, but it's recommended that
 +this only be used on an otherwise quiet repository.  Using --force
  is not necessary for an initial import into an empty repository.
  
  
@@@ -231,11 -231,11 +231,11 @@@ Date Format
  ~~~~~~~~~~~~
  The following date formats are supported.  A frontend should select
  the format it will use for this import by passing the format name
 -in the \--date-format=<fmt> command-line option.
 +in the --date-format=<fmt> command-line option.
  
  `raw`::
  	This is the Git native format and is `<time> SP <offutc>`.
 -	It is also fast-import's default format, if \--date-format was
 +	It is also fast-import's default format, if --date-format was
  	not specified.
  +
  The time of the event is specified by `<time>` as the number of
@@@ -350,6 -350,11 +350,11 @@@ and control the current import process
  	unless the `done` feature was requested using the
  	`--done` command-line option or `feature done` command.
  
+ `get-mark`::
+ 	Causes fast-import to print the SHA-1 corresponding to a mark
+ 	to the file descriptor set with `--cat-blob-fd`, or `stdout` if
+ 	unspecified.
+ 
  `cat-blob`::
  	Causes fast-import to print a blob in 'cat-file --batch'
  	format to the file descriptor set with `--cat-blob-fd` or
@@@ -437,7 -442,7 +442,7 @@@ the email address from the other field
  of bytes, except `LT`, `GT` and `LF`.  `<name>` is typically UTF-8 encoded.
  
  The time of the change is specified by `<when>` using the date format
 -that was selected by the \--date-format=<fmt> command-line option.
 +that was selected by the --date-format=<fmt> command-line option.
  See ``Date Formats'' above for the set of supported formats, and
  their syntax.
  
@@@ -600,7 -605,7 +605,7 @@@ be removed from the branch
  See `filemodify` above for a detailed description of `<path>`.
  
  `filecopy`
 -^^^^^^^^^^^^
 +^^^^^^^^^^
  Recursively copies an existing file or subdirectory to a different
  location within the branch.  The existing file or directory must
  exist.  If the destination exists it will be completely replaced
@@@ -888,7 -893,7 +893,7 @@@ save out all current branch refs, tags 
  ....
  
  Note that fast-import automatically switches packfiles when the current
 -packfile reaches \--max-pack-size, or 4 GiB, whichever limit is
 +packfile reaches --max-pack-size, or 4 GiB, whichever limit is
  smaller.  During an automatic packfile switch fast-import does not update
  the branch refs, tags or marks.
  
@@@ -930,6 -935,25 +935,25 @@@ Placing a `progress` command immediatel
  inform the reader when the `checkpoint` has been completed and it
  can safely access the refs that fast-import updated.
  
+ `get-mark`
+ ~~~~~~~~~~
+ Causes fast-import to print the SHA-1 corresponding to a mark to
+ stdout or to the file descriptor previously arranged with the
+ `--cat-blob-fd` argument. The command otherwise has no impact on the
+ current import; its purpose is to retrieve SHA-1s that later commits
+ might want to refer to in their commit messages.
+ 
+ ....
+ 	'get-mark' SP ':' <idnum> LF
+ ....
+ 
+ This command can be used anywhere in the stream that comments are
+ accepted.  In particular, the `get-mark` command can be used in the
+ middle of a commit but not in the middle of a `data` command.
+ 
+ See ``Responses To Commands'' below for details about how to read
+ this output safely.
+ 
  `cat-blob`
  ~~~~~~~~~~
  Causes fast-import to print a blob to a file descriptor previously
@@@ -1000,7 -1024,8 +1024,8 @@@ Output uses the same format as `git ls-
  ====
  
  The <dataref> represents the blob, tree, or commit object at <path>
- and can be used in later 'cat-blob', 'filemodify', or 'ls' commands.
+ and can be used in later 'get-mark', 'cat-blob', 'filemodify', or
+ 'ls' commands.
  
  If there is no file or subtree at that path, 'git fast-import' will
  instead report
@@@ -1042,9 -1067,11 +1067,11 @@@ import-marks-if-exists:
  	"feature import-marks-if-exists" like a corresponding
  	command-line option silently skips a nonexistent file.
  
+ get-mark::
  cat-blob::
  ls::
- 	Require that the backend support the 'cat-blob' or 'ls' command.
+ 	Require that the backend support the 'get-mark', 'cat-blob',
+ 	or 'ls' command respectively.
  	Versions of fast-import not supporting the specified command
  	will exit with a message indicating so.
  	This lets the import error out early with a clear message,
@@@ -1124,11 -1151,11 +1151,11 @@@ bidirectional pipes
  	git fast-import >fast-import-output
  ====
  
- A frontend set up this way can use `progress`, `ls`, and `cat-blob`
- commands to read information from the import in progress.
+ A frontend set up this way can use `progress`, `get-mark`, `ls`, and
+ `cat-blob` commands to read information from the import in progress.
  
  To avoid deadlock, such frontends must completely consume any
- pending output from `progress`, `ls`, and `cat-blob` before
+ pending output from `progress`, `ls`, `get-mark`, and `cat-blob` before
  performing writes to fast-import that might block.
  
  Crash Reports
@@@ -1226,7 -1253,7 +1253,7 @@@ users of fast-import, and are offered h
  Use One Mark Per Commit
  ~~~~~~~~~~~~~~~~~~~~~~~
  When doing a repository conversion, use a unique mark per commit
 -(`mark :<n>`) and supply the \--export-marks option on the command
 +(`mark :<n>`) and supply the --export-marks option on the command
  line.  fast-import will dump a file which lists every mark and the Git
  object SHA-1 that corresponds to it.  If the frontend can tie
  the marks back to the source repository, it is easy to verify the
@@@ -1291,7 -1318,7 +1318,7 @@@ even for considerably large projects (1
  
  However repacking the repository is necessary to improve data
  locality and access performance.  It can also take hours on extremely
 -large projects (especially if -f and a large \--window parameter is
 +large projects (especially if -f and a large --window parameter is
  used).  Since repacking is safe to run alongside readers and writers,
  run the repack in the background and let it finish when it finishes.
  There is no reason to wait to explore your new Git project!
@@@ -1305,7 -1332,7 +1332,7 @@@ Repacking Historical Dat
  ~~~~~~~~~~~~~~~~~~~~~~~~~
  If you are repacking very old imported data (e.g. older than the
  last year), consider expending some extra CPU time and supplying
 -\--window=50 (or higher) when you run 'git repack'.
 +--window=50 (or higher) when you run 'git repack'.
  This will take longer, but will also produce a smaller packfile.
  You only need to expend the effort once, and everyone using your
  project will benefit from the smaller repository.
@@@ -1407,7 -1434,7 +1434,7 @@@ branch, their in-memory storage size ca
  fast-import automatically moves active branches to inactive status based on
  a simple least-recently-used algorithm.  The LRU chain is updated on
  each `commit` command.  The maximum number of active branches can be
 -increased or decreased on the command line with \--active-branches=.
 +increased or decreased on the command line with --active-branches=.
  
  per active tree
  ~~~~~~~~~~~~~~~
diff --combined fast-import.c
index d7ed065381,2b02f3f94d..9d949d1f77
--- a/fast-import.c
+++ b/fast-import.c
@@@ -134,16 -134,17 +134,17 @@@ Format of STDIN stream
    ts    ::= # time since the epoch in seconds, ascii base10 notation;
    tz    ::= # GIT style timezone;
  
-      # note: comments, ls and cat requests may appear anywhere
-      # in the input, except within a data command.  Any form
-      # of the data command always escapes the related input
-      # from comment processing.
+      # note: comments, get-mark, ls-tree, and cat-blob requests may
+      # appear anywhere in the input, except within a data command. Any
+      # form of the data command always escapes the related input from
+      # comment processing.
       #
       # In case it is not clear, the '#' that starts the comment
       # must be the first character on that line (an lf
       # preceded it).
       #
  
+   get_mark ::= 'get-mark' sp idnum lf;
    cat_blob ::= 'cat-blob' sp (hexsha1 | idnum) lf;
    ls_tree  ::= 'ls' sp (hexsha1 | idnum) sp path_str lf;
  
@@@ -372,6 -373,7 +373,7 @@@ static volatile sig_atomic_t checkpoint
  static int cat_blob_fd = STDOUT_FILENO;
  
  static void parse_argv(void);
+ static void parse_get_mark(const char *p);
  static void parse_cat_blob(const char *p);
  static void parse_ls(const char *p, struct branch *b);
  
@@@ -405,7 -407,7 +407,7 @@@ static void dump_marks_helper(FILE *, u
  
  static void write_crash_report(const char *err)
  {
 -	char *loc = git_path("fast_import_crash_%"PRIuMAX, (uintmax_t) getpid());
 +	const char *loc = git_path("fast_import_crash_%"PRIuMAX, (uintmax_t) getpid());
  	FILE *rpt = fopen(loc, "w");
  	struct branch *b;
  	unsigned long lu;
@@@ -1692,13 -1694,13 +1694,13 @@@ static int update_branch(struct branch 
  	unsigned char old_sha1[20];
  	struct strbuf err = STRBUF_INIT;
  
 -	if (read_ref(b->name, old_sha1))
 -		hashclr(old_sha1);
  	if (is_null_sha1(b->sha1)) {
  		if (b->delete)
 -			delete_ref(b->name, old_sha1, 0);
 +			delete_ref(b->name, NULL, 0);
  		return 0;
  	}
 +	if (read_ref(b->name, old_sha1))
 +		hashclr(old_sha1);
  	if (!force_update && !is_null_sha1(old_sha1)) {
  		struct commit *old_cmit, *new_cmit;
  
@@@ -1907,6 -1909,10 +1909,10 @@@ static int read_next_command(void
  			rc->prev->next = rc;
  			cmd_tail = rc;
  		}
+ 		if (skip_prefix(command_buf.buf, "get-mark ", &p)) {
+ 			parse_get_mark(p);
+ 			continue;
+ 		}
  		if (skip_prefix(command_buf.buf, "cat-blob ", &p)) {
  			parse_cat_blob(p);
  			continue;
@@@ -2919,6 -2925,23 +2925,23 @@@ static void cat_blob(struct object_entr
  		free(buf);
  }
  
+ static void parse_get_mark(const char *p)
+ {
+ 	struct object_entry *oe = oe;
+ 	char output[42];
+ 
+ 	/* get-mark SP <object> LF */
+ 	if (*p != ':')
+ 		die("Not a mark: %s", p);
+ 
+ 	oe = find_mark(parse_mark_ref_eol(p));
+ 	if (!oe)
+ 		die("Unknown mark: %s", command_buf.buf);
+ 
+ 	snprintf(output, sizeof(output), "%s\n", sha1_to_hex(oe->idx.sha1));
+ 	cat_blob_write(output, 41);
+ }
+ 
  static void parse_cat_blob(const char *p)
  {
  	struct object_entry *oe = oe;
@@@ -3113,9 -3136,12 +3136,9 @@@ static void parse_progress(void
  
  static char* make_fast_import_path(const char *path)
  {
 -	struct strbuf abs_path = STRBUF_INIT;
 -
  	if (!relative_marks_paths || is_absolute_path(path))
  		return xstrdup(path);
 -	strbuf_addf(&abs_path, "%s/info/fast-import/%s", get_git_dir(), path);
 -	return strbuf_detach(&abs_path, NULL);
 +	return xstrdup(git_path("info/fast-import/%s", path));
  }
  
  static void option_import_marks(const char *marks,
@@@ -3240,6 -3266,8 +3263,8 @@@ static int parse_one_feature(const cha
  		option_import_marks(arg, from_stream, 1);
  	} else if (skip_prefix(feature, "export-marks=", &arg)) {
  		option_export_marks(arg);
+ 	} else if (!strcmp(feature, "get-mark")) {
+ 		; /* Don't die - this feature is supported */
  	} else if (!strcmp(feature, "cat-blob")) {
  		; /* Don't die - this feature is supported */
  	} else if (!strcmp(feature, "relative-marks")) {