[PATCH 4/4] convert: Added core.refilteronadd feature.

["Henrik Grubbström" <grubba@grubba.org>]

From: Henrik Grubbström (Grubba) <grubba@grubba.org>

When having $Id$ tags in other versioning systems, it is customary
to recalculate the tags in the source on commit or equvivalent.
This commit adds a configuration option to git that causes source
files to pass through a conversion roundtrip when added to the index.

Signed-off-by: Henrik Grubbström <grubba@grubba.org>
---
 Documentation/config.txt |    6 +++++
 cache.h                  |    1 +
 config.c                 |    5 ++++
 environment.c            |    1 +
 sha1_file.c              |   57 ++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 70 insertions(+), 0 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 664de6b..900b095 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -533,6 +533,12 @@ core.sparseCheckout::
 	Enable "sparse checkout" feature. See section "Sparse checkout" in
 	linkgit:git-read-tree[1] for more information.
 
+core.refilterOnAdd::
+	Enable "refilter on add" feature. This causes source files to be
+	behave as if they were checked out after a linkgit:git-add[1].
+	This is typically usefull if eg the `ident` attribute is active,
+	in which case the $Id$ tags will be updated.
+
 add.ignore-errors::
 	Tells 'git add' to continue adding files when some files cannot be
 	added due to indexing errors. Equivalent to the '--ignore-errors'
diff --git a/cache.h b/cache.h
index 1c9f491..beb60f9 100644
--- a/cache.h
+++ b/cache.h
@@ -540,6 +540,7 @@ extern int read_replace_refs;
 extern int fsync_object_files;
 extern int core_preload_index;
 extern int core_apply_sparse_checkout;
+extern int core_refilter_on_add;
 
 enum safe_crlf {
 	SAFE_CRLF_FALSE = 0,
diff --git a/config.c b/config.c
index 6963fbe..b1db505 100644
--- a/config.c
+++ b/config.c
@@ -523,6 +523,11 @@ static int git_default_core_config(const char *var, const char *value)
 		return 0;
 	}
 
+	if (!strcmp(var, "core.refilteronadd")) {
+		core_refilter_on_add = git_config_bool(var, value);
+		return 0;
+	}
+
 	/* Add other config variables here and to Documentation/config.txt. */
 	return 0;
 }
diff --git a/environment.c b/environment.c
index 739ec27..eed7ef1 100644
--- a/environment.c
+++ b/environment.c
@@ -52,6 +52,7 @@ enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 char *notes_ref_name;
 int grafts_replace_parents = 1;
 int core_apply_sparse_checkout;
+int core_refilter_on_add;
 
 /* Parallel index stat data preload? */
 int core_preload_index = 0;
diff --git a/sha1_file.c b/sha1_file.c
index fd8c5df..f2659cb 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2459,6 +2459,54 @@ int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object,
 	return ret;
 }
 
+static int refilter_fd(int fd, struct stat *st, const char *path)
+{
+	int ret = -1;
+	size_t size = xsize_t(st->st_size);
+	struct strbuf gbuf = STRBUF_INIT;
+
+	if (!S_ISREG(st->st_mode)) {
+		struct strbuf sbuf = STRBUF_INIT;
+		if (strbuf_read(&sbuf, fd, 4096) >= 0)
+			ret = convert_to_git(path, sbuf.buf, sbuf.len, &gbuf, safe_crlf, 0);
+		else
+			ret = -1;
+		strbuf_release(&sbuf);
+	} else if (size) {
+		void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+		ret = convert_to_git(path, buf, size, &gbuf, safe_crlf, 0);
+		munmap(buf, size);
+	} else
+		ret = -1;
+
+	if (ret > 0) {
+		/* Something happened during conversion to git.
+		 * Now convert it back, and save the result.
+		 */
+		struct strbuf obuf = STRBUF_INIT;
+
+		lseek(fd, 0, SEEK_SET);
+
+		if (convert_to_working_tree(path, gbuf.buf, gbuf.len, &obuf)) {
+			if (write_or_whine(fd, obuf.buf, obuf.len, path))
+				ftruncate(fd, obuf.len);
+			else
+				ret = -1;
+		} else {
+			if (write_or_whine(fd, gbuf.buf, gbuf.len, path))
+				ftruncate(fd, gbuf.len);
+			else
+				ret = -1;
+		}
+
+		strbuf_release(&obuf);
+	}
+	strbuf_release(&gbuf);
+
+	close(fd);
+	return ret;
+}
+
 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
 {
 	int fd;
@@ -2473,6 +2521,15 @@ int index_path(unsigned char *sha1, const char *path, struct stat *st, int write
 		if (index_fd(sha1, fd, st, write_object, OBJ_BLOB, path) < 0)
 			return error("%s: failed to insert into database",
 				     path);
+		if (write_object && core_refilter_on_add) {
+			fd = open(path, O_RDWR);
+			if (fd < 0)
+				return error("open(\"%s\"): %s", path,
+					     strerror(errno));
+			if (refilter_fd(fd, st, path) < 0)
+				return error("%s: failed to refilter file",
+					     path);
+		}
 		break;
 	case S_IFLNK:
 		if (strbuf_readlink(&sb, path, st->st_size)) {
-- 
1.6.4.122.g6ffd7