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

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<redacted>
---
  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);