thodg/libgit2

diff --git a/include/git2/odb.h b/include/git2/odb.h
index 114f6b3..4f1e18b 100644
--- a/include/git2/odb.h
+++ b/include/git2/odb.h
@@ -247,7 +247,7 @@ GIT_EXTERN(int) git_odb_write(git_oid *out, git_odb *odb, const void *data, size
  * @param type type of the object that will be written
  * @return 0 if the stream was created; error code otherwise
  */
-GIT_EXTERN(int) git_odb_open_wstream(git_odb_stream **out, git_odb *db, size_t size, git_otype type);
+GIT_EXTERN(int) git_odb_open_wstream(git_odb_stream **out, git_odb *db, git_off_t size, git_otype type);
 
 /**
  * Write to an odb stream
diff --git a/include/git2/odb_backend.h b/include/git2/odb_backend.h
index 4d772ca..b17cfd8 100644
--- a/include/git2/odb_backend.h
+++ b/include/git2/odb_backend.h
@@ -86,8 +86,8 @@ struct git_odb_stream {
 	unsigned int mode;
 	void *hash_ctx;
 
-	size_t declared_size;
-	size_t received_bytes;
+	git_off_t declared_size;
+	git_off_t received_bytes;
 
 	/**
 	 * Write at most `len` bytes into `buffer` and advance the stream.
diff --git a/include/git2/sys/odb_backend.h b/include/git2/sys/odb_backend.h
index 1fc3c31..0a51c6d 100644
--- a/include/git2/sys/odb_backend.h
+++ b/include/git2/sys/odb_backend.h
@@ -53,7 +53,7 @@ struct git_odb_backend {
 		git_odb_backend *, const git_oid *, const void *, size_t, git_otype);
 
 	int (* writestream)(
-		git_odb_stream **, git_odb_backend *, size_t, git_otype);
+		git_odb_stream **, git_odb_backend *, git_off_t, git_otype);
 
 	int (* readstream)(
 		git_odb_stream **, git_odb_backend *, const git_oid *);
diff --git a/src/blob.c b/src/blob.c
index 4721650..07c4d92 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -76,10 +76,11 @@ static int write_file_stream(
 	int fd, error;
 	char buffer[FILEIO_BUFSIZE];
 	git_odb_stream *stream = NULL;
-	ssize_t read_len = -1, written = 0;
+	ssize_t read_len = -1;
+	git_off_t written = 0;
 
 	if ((error = git_odb_open_wstream(
-			&stream, odb, (size_t)file_size, GIT_OBJ_BLOB)) < 0)
+			&stream, odb, file_size, GIT_OBJ_BLOB)) < 0)
 		return error;
 
 	if ((fd = git_futils_open_ro(path)) < 0) {
diff --git a/src/odb.c b/src/odb.c
index 5dccb63..deb9d5c 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -50,7 +50,7 @@ static git_cache *odb_cache(git_odb *odb)
 
 static int load_alternates(git_odb *odb, const char *objects_dir, int alternate_depth);
 
-int git_odb__format_object_header(char *hdr, size_t n, size_t obj_len, git_otype obj_type)
+int git_odb__format_object_header(char *hdr, size_t n, git_off_t obj_len, git_otype obj_type)
 {
 	const char *type_str = git_object_type2string(obj_type);
 	int len = p_snprintf(hdr, n, "%s %"PRIuZ, type_str, obj_len);
@@ -330,10 +330,15 @@ static void fake_wstream__free(git_odb_stream *_stream)
 	git__free(stream);
 }
 
-static int init_fake_wstream(git_odb_stream **stream_p, git_odb_backend *backend, size_t size, git_otype type)
+static int init_fake_wstream(git_odb_stream **stream_p, git_odb_backend *backend, git_off_t size, git_otype type)
 {
 	fake_wstream *stream;
 
+	if (!git__is_ssizet(size)) {
+		giterr_set(GITERR_ODB, "object size too large to keep in memory");
+		return -1;
+	}
+
 	stream = git__calloc(1, sizeof(fake_wstream));
 	GITERR_CHECK_ALLOC(stream);
 
@@ -940,7 +945,7 @@ int git_odb_write(
 	return error;
 }
 
-static void hash_header(git_hash_ctx *ctx, size_t size, git_otype type)
+static void hash_header(git_hash_ctx *ctx, git_off_t size, git_otype type)
 {
 	char header[64];
 	int hdrlen;
@@ -950,7 +955,7 @@ static void hash_header(git_hash_ctx *ctx, size_t size, git_otype type)
 }
 
 int git_odb_open_wstream(
-	git_odb_stream **stream, git_odb *db, size_t size, git_otype type)
+	git_odb_stream **stream, git_odb *db, git_off_t size, git_otype type)
 {
 	size_t i, writes = 0;
 	int error = GIT_ERROR;
diff --git a/src/odb.h b/src/odb.h
index 61dd9a7..281bd3a 100644
--- a/src/odb.h
+++ b/src/odb.h
@@ -49,7 +49,7 @@ int git_odb__hashobj(git_oid *id, git_rawobj *obj);
 /*
  * Format the object header such as it would appear in the on-disk object
  */
-int git_odb__format_object_header(char *hdr, size_t n, size_t obj_len, git_otype obj_type);
+int git_odb__format_object_header(char *hdr, size_t n, git_off_t obj_len, git_otype obj_type);
 /*
  * Hash an open file descriptor.
  * This is a performance call when the contents of a fd need to be hashed,
diff --git a/src/odb_loose.c b/src/odb_loose.c
index bfd9558..99b8f7c 100644
--- a/src/odb_loose.c
+++ b/src/odb_loose.c
@@ -834,7 +834,7 @@ static void loose_backend__stream_free(git_odb_stream *_stream)
 	git__free(stream);
 }
 
-static int loose_backend__stream(git_odb_stream **stream_out, git_odb_backend *_backend, size_t length, git_otype type)
+static int loose_backend__stream(git_odb_stream **stream_out, git_odb_backend *_backend, git_off_t length, git_otype type)
 {
 	loose_backend *backend;
 	loose_writestream *stream = NULL;
@@ -842,7 +842,7 @@ static int loose_backend__stream(git_odb_stream **stream_out, git_odb_backend *_
 	git_buf tmp_path = GIT_BUF_INIT;
 	int hdrlen;
 
-	assert(_backend);
+	assert(_backend && length >= 0);
 
 	backend = (loose_backend *)_backend;
 	*stream_out = NULL;