[PATCH 3/5] archive: delegate blob reading to backend

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

archive-tar.c and archive-zip.c now perform conversion check, with
help of sha1_file_to_archive() from archive.c

This gives backends more freedom in dealing with (streaming) large
blobs.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 archive-tar.c |   20 +++++++++++++++++---
 archive-zip.c |   14 ++++++++++++--
 archive.c     |   28 +++++++++++-----------------
 archive.h     |   10 +++++++++-
 4 files changed, 49 insertions(+), 23 deletions(-)

diff --git a/archive-tar.c b/archive-tar.c
index 6c8a0bd..61821f4 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -161,11 +161,15 @@ static int write_extended_header(struct archiver_args *args,
 }
 
 static int write_tar_entry(struct archiver_args *args,
-		const unsigned char *sha1, const char *path, size_t pathlen,
-		unsigned int mode, void *buffer, unsigned long size)
+			   const unsigned char *sha1,
+			   const char *path, size_t pathlen,
+			   unsigned int mode)
 {
 	struct ustar_header header;
 	struct strbuf ext_header = STRBUF_INIT;
+	unsigned int old_mode = mode;
+	unsigned long size;
+	void *buffer;
 	int err = 0;
 
 	memset(&header, 0, sizeof(header));
@@ -199,7 +203,17 @@ static int write_tar_entry(struct archiver_args *args,
 	} else
 		memcpy(header.name, path, pathlen);
 
-	if (S_ISLNK(mode) && buffer) {
+	if (S_ISLNK(mode) || S_ISREG(mode)) {
+		enum object_type type;
+		buffer = sha1_file_to_archive(args, path, sha1, old_mode, &type, &size);
+		if (!buffer)
+			return error("cannot read %s", sha1_to_hex(sha1));
+	} else {
+		buffer = NULL;
+		size = 0;
+	}
+
+	if (S_ISLNK(mode)) {
 		if (size > sizeof(header.linkname)) {
 			sprintf(header.linkname, "see %s.paxheader",
 			        sha1_to_hex(sha1));
diff --git a/archive-zip.c b/archive-zip.c
index 02d1f37..f8039ba 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -121,8 +121,9 @@ static void *zlib_deflate(void *data, unsigned long size,
 }
 
 static int write_zip_entry(struct archiver_args *args,
-		const unsigned char *sha1, const char *path, size_t pathlen,
-		unsigned int mode, void *buffer, unsigned long size)
+			   const unsigned char *sha1,
+			   const char *path, size_t pathlen,
+			   unsigned int mode)
 {
 	struct zip_local_header header;
 	struct zip_dir_header dirent;
@@ -134,6 +135,8 @@ static int write_zip_entry(struct archiver_args *args,
 	int method;
 	unsigned char *out;
 	void *deflated = NULL;
+	void *buffer;
+	unsigned long size;
 
 	crc = crc32(0, NULL, 0);
 
@@ -148,7 +151,14 @@ static int write_zip_entry(struct archiver_args *args,
 		out = NULL;
 		uncompressed_size = 0;
 		compressed_size = 0;
+		buffer = NULL;
+		size = 0;
 	} else if (S_ISREG(mode) || S_ISLNK(mode)) {
+		enum object_type type;
+		buffer = sha1_file_to_archive(args, path, sha1, mode, &type, &size);
+		if (!buffer)
+			return error("cannot read %s", sha1_to_hex(sha1));
+
 		method = 0;
 		attr2 = S_ISLNK(mode) ? ((mode | 0777) << 16) :
 			(mode & 0111) ? ((mode) << 16) : 0;
diff --git a/archive.c b/archive.c
index 1ee837d..cd083ea 100644
--- a/archive.c
+++ b/archive.c
@@ -59,12 +59,15 @@ static void format_subst(const struct commit *commit,
 	free(to_free);
 }
 
-static void *sha1_file_to_archive(const char *path, const unsigned char *sha1,
-		unsigned int mode, enum object_type *type,
-		unsigned long *sizep, const struct commit *commit)
+void *sha1_file_to_archive(const struct archiver_args *args,
+			   const char *path, const unsigned char *sha1,
+			   unsigned int mode, enum object_type *type,
+			   unsigned long *sizep)
 {
 	void *buffer;
+	const struct commit *commit = args->convert ? args->commit : NULL;
 
+	path += args->baselen;
 	buffer = read_sha1_file(sha1, type, sizep);
 	if (buffer && S_ISREG(mode)) {
 		struct strbuf buf = STRBUF_INIT;
@@ -109,12 +112,9 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 	write_archive_entry_fn_t write_entry = c->write_entry;
 	struct git_attr_check check[2];
 	const char *path_without_prefix;
-	int convert = 0;
 	int err;
-	enum object_type type;
-	unsigned long size;
-	void *buffer;
 
+	args->convert = 0;
 	strbuf_reset(&path);
 	strbuf_grow(&path, PATH_MAX);
 	strbuf_add(&path, args->base, args->baselen);
@@ -126,28 +126,22 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 	if (!git_check_attr(path_without_prefix, ARRAY_SIZE(check), check)) {
 		if (ATTR_TRUE(check[0].value))
 			return 0;
-		convert = ATTR_TRUE(check[1].value);
+		args->convert = ATTR_TRUE(check[1].value);
 	}
 
 	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
 		strbuf_addch(&path, '/');
 		if (args->verbose)
 			fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
-		err = write_entry(args, sha1, path.buf, path.len, mode, NULL, 0);
+		err = write_entry(args, sha1, path.buf, path.len, mode);
 		if (err)
 			return err;
 		return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 	}
 
-	buffer = sha1_file_to_archive(path_without_prefix, sha1, mode,
-			&type, &size, convert ? args->commit : NULL);
-	if (!buffer)
-		return error("cannot read %s", sha1_to_hex(sha1));
 	if (args->verbose)
 		fprintf(stderr, "%.*s\n", (int)path.len, path.buf);
-	err = write_entry(args, sha1, path.buf, path.len, mode, buffer, size);
-	free(buffer);
-	return err;
+	return write_entry(args, sha1, path.buf, path.len, mode);
 }
 
 int write_archive_entries(struct archiver_args *args,
@@ -167,7 +161,7 @@ int write_archive_entries(struct archiver_args *args,
 		if (args->verbose)
 			fprintf(stderr, "%.*s\n", (int)len, args->base);
 		err = write_entry(args, args->tree->object.sha1, args->base,
-				len, 040777, NULL, 0);
+				  len, 040777);
 		if (err)
 			return err;
 	}
diff --git a/archive.h b/archive.h
index 2b0884f..895afcd 100644
--- a/archive.h
+++ b/archive.h
@@ -11,6 +11,7 @@ struct archiver_args {
 	const char **pathspec;
 	unsigned int verbose : 1;
 	unsigned int worktree_attributes : 1;
+	unsigned int convert : 1;
 	int compression_level;
 };
 
@@ -27,11 +28,18 @@ extern void register_archiver(struct archiver *);
 extern void init_tar_archiver(void);
 extern void init_zip_archiver(void);
 
-typedef int (*write_archive_entry_fn_t)(struct archiver_args *args, const unsigned char *sha1, const char *path, size_t pathlen, unsigned int mode, void *buffer, unsigned long size);
+typedef int (*write_archive_entry_fn_t)(struct archiver_args *args,
+					const unsigned char *sha1,
+					const char *path, size_t pathlen,
+					unsigned int mode);
 
 extern int write_archive_entries(struct archiver_args *args, write_archive_entry_fn_t write_entry);
 extern int write_archive(int argc, const char **argv, const char *prefix, int setup_prefix, const char *name_hint, int remote);
 
 const char *archive_format_from_filename(const char *filename);
+extern void *sha1_file_to_archive(const struct archiver_args *args,
+				  const char *path, const unsigned char *sha1,
+				  unsigned int mode, enum object_type *type,
+				  unsigned long *sizep);
 
 #endif	/* ARCHIVE_H */
-- 
1.7.8.36.g69ee2