Migrate ODB files to new error handling

This migrates odb.c, odb_loose.c, odb_pack.c and pack.c to
the new style of error handling.  Also got the unix and win32
versions of map.c.  There are some minor changes to other
files but no others were completely converted.

This also contains an update to filebuf so that a zeroed out
filebuf will not think that the fd (== 0) is actually open
(and inadvertently call close() on fd 0 if cleaned up).

Lastly, this was built and tested on win32 and contains a
bunch of fixes for the win32 build which was pretty broken.

1 files changed, 57 insertions, 56 deletions

diff --git a/src/odb.c b/src/odb.c
index edb9c72a0..782a77dc4 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -188,7 +188,7 @@ int git_odb_hashfile(git_oid *out, const char *path, git_otype type)
 	git_off_t size;
 	int result, fd = git_futils_open_ro(path);
 	if (fd < 0)
-		return -1;
+		return fd;
 
 	if ((size = git_futils_filesize(fd)) < 0 || !git__is_sizet(size)) {
 		giterr_set(GITERR_OS, "File size overflow for 32-bit systems");
@@ -507,23 +507,20 @@ int git_odb_read_header(size_t *len_p, git_otype *type_p, git_odb *db, const git
 			error = b->read_header(len_p, type_p, b, id);
 	}
 
-	if (error == GIT_EPASSTHROUGH)
+	if (!error || error == GIT_EPASSTHROUGH)
 		return 0;
 
 	/*
 	 * no backend could read only the header.
 	 * try reading the whole object and freeing the contents
 	 */
-	if (error < 0) {
-		if ((error = git_odb_read(&object, db, id)) < GIT_SUCCESS)
-			return error; /* error already set - pass through */
-
-		*len_p = object->raw.len;
-		*type_p = object->raw.type;
-		git_odb_object_free(object);
-	}
+	if ((error = git_odb_read(&object, db, id)) < 0)
+		return error; /* error already set - pass along */
 
-	return GIT_SUCCESS;
+	*len_p = object->raw.len;
+	*type_p = object->raw.type;
+	git_odb_object_free(object);
+	return 0;
 }
 
 int git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id)
@@ -536,7 +533,7 @@ int git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id)
 
 	*out = git_cache_get(&db->cache, id);
 	if (*out != NULL)
-		return GIT_SUCCESS;
+		return 0;
 
 	for (i = 0; i < db->backends.length && error < 0; ++i) {
 		backend_internal *internal = git_vector_get(&db->backends, i);
@@ -546,15 +543,15 @@ int git_odb_read(git_odb_object **out, git_odb *db, const git_oid *id)
 			error = b->read(&raw.data, &raw.len, &raw.type, b, id);
 	}
 
-	if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS) {
-		*out = git_cache_try_store(&db->cache, new_odb_object(id, &raw));
-		return GIT_SUCCESS;
-	}
+	if (error && error != GIT_EPASSTHROUGH)
+		return error;
 
-	return git__rethrow(error, "Failed to read object");
+	*out = git_cache_try_store(&db->cache, new_odb_object(id, &raw));
+	return 0;
 }
 
-int git_odb_read_prefix(git_odb_object **out, git_odb *db, const git_oid *short_id, unsigned int len)
+int git_odb_read_prefix(
+	git_odb_object **out, git_odb *db, const git_oid *short_id, unsigned int len)
 {
 	unsigned int i;
 	int error = GIT_ENOTFOUND;
@@ -565,7 +562,7 @@ int git_odb_read_prefix(git_odb_object **out, git_odb *db, const git_oid *short_
 	assert(out && db);
 
 	if (len < GIT_OID_MINPREFIXLEN)
-		return git__throw(GIT_EAMBIGUOUSOIDPREFIX, "Failed to lookup object. Prefix length is lower than %d.", GIT_OID_MINPREFIXLEN);
+		return git_odb__error_ambiguous("prefix length too short");
 
 	if (len > GIT_OID_HEXSZ)
 		len = GIT_OID_HEXSZ;
@@ -573,7 +570,7 @@ int git_odb_read_prefix(git_odb_object **out, git_odb *db, const git_oid *short_
 	if (len == GIT_OID_HEXSZ) {
 		*out = git_cache_get(&db->cache, short_id);
 		if (*out != NULL)
-			return GIT_SUCCESS;
+			return 0;
 	}
 
 	for (i = 0; i < db->backends.length && found < 2; ++i) {
@@ -582,33 +579,24 @@ int git_odb_read_prefix(git_odb_object **out, git_odb *db, const git_oid *short_
 
 		if (b->read != NULL) {
 			error = b->read_prefix(&full_oid, &raw.data, &raw.len, &raw.type, b, short_id, len);
-			switch (error) {
-			case GIT_SUCCESS:
+			if (!error)
 				found++;
-				break;
-			case GIT_ENOTFOUND:
-			case GIT_EPASSTHROUGH:
-				break;
-			case GIT_EAMBIGUOUSOIDPREFIX:
-				return git__rethrow(error, "Failed to read object. Ambiguous sha1 prefix");
-			default:
-				return git__rethrow(error, "Failed to read object");
-			}
+			else if (error != GIT_ENOTFOUND && error != GIT_EPASSTHROUGH)
+				return error;
 		}
 	}
 
-	if (found == 1) {
-		*out = git_cache_try_store(&db->cache, new_odb_object(&full_oid, &raw));
-	} else if (found > 1) {
-		return git__throw(GIT_EAMBIGUOUSOIDPREFIX, "Failed to read object. Ambiguous sha1 prefix");
-	} else {
-		return git__throw(GIT_ENOTFOUND, "Failed to read object. Object not found");
-	}
+	if (found == 0)
+		return git_odb__error_notfound("no match for prefix");
+	if (found > 1)
+		return git_odb__error_ambiguous("multiple matches for prefix");
 
-	return GIT_SUCCESS;
+	*out = git_cache_try_store(&db->cache, new_odb_object(&full_oid, &raw));
+	return 0;
 }
 
-int git_odb_write(git_oid *oid, git_odb *db, const void *data, size_t len, git_otype type)
+int git_odb_write(
+	git_oid *oid, git_odb *db, const void *data, size_t len, git_otype type)
 {
 	unsigned int i;
 	int error = GIT_ERROR;
@@ -628,24 +616,25 @@ int git_odb_write(git_oid *oid, git_odb *db, const void *data, size_t len, git_o
 			error = b->write(oid, b, data, len, type);
 	}
 
-	if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS)
-		return GIT_SUCCESS;
+	if (!error || error == GIT_EPASSTHROUGH)
+		return 0;
 
 	/* if no backends were able to write the object directly, we try a streaming
 	 * write to the backends; just write the whole object into the stream in one
 	 * push */
 
-	if ((error = git_odb_open_wstream(&stream, db, len, type)) == GIT_SUCCESS) {
-		stream->write(stream, data, len);
-		error = stream->finalize_write(oid, stream);
-		stream->free(stream);
-		return GIT_SUCCESS;
-	}
+	if ((error = git_odb_open_wstream(&stream, db, len, type)) != 0)
+		return error;
 
-	return git__rethrow(error, "Failed to write object");
+	stream->write(stream, data, len);
+	error = stream->finalize_write(oid, stream);
+	stream->free(stream);
+
+	return error;
 }
 
-int git_odb_open_wstream(git_odb_stream **stream, git_odb *db, size_t size, git_otype type)
+int git_odb_open_wstream(
+	git_odb_stream **stream, git_odb *db, size_t size, git_otype type)
 {
 	unsigned int i;
 	int error = GIT_ERROR;
@@ -666,10 +655,10 @@ int git_odb_open_wstream(git_odb_stream **stream, git_odb *db, size_t size, git_
 			error = init_fake_wstream(stream, b, size, type);
 	}
 
-	if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS)
-		return GIT_SUCCESS;
+	if (error == GIT_EPASSTHROUGH)
+		error = 0;
 
-	return git__rethrow(error, "Failed to open write stream");
+	return error;
 }
 
 int git_odb_open_rstream(git_odb_stream **stream, git_odb *db, const git_oid *oid)
@@ -687,9 +676,21 @@ int git_odb_open_rstream(git_odb_stream **stream, git_odb *db, const git_oid *oi
 			error = b->readstream(stream, b, oid);
 	}
 
-	if (error == GIT_EPASSTHROUGH || error == GIT_SUCCESS)
-		return GIT_SUCCESS;
+	if (error == GIT_EPASSTHROUGH)
+		error = 0;
 
-	return git__rethrow(error, "Failed to open read stream");
+	return error;
+}
+
+int git_odb__error_notfound(const char *message)
+{
+	giterr_set(GITERR_ODB, "Object not found - %s", message);
+	return GIT_ENOTFOUND;
+}
+
+int git_odb__error_ambiguous(const char *message)
+{
+	giterr_set(GITERR_ODB, "Ambiguous SHA1 prefix - %s", message);
+	return GIT_EAMBIGUOUS;
 }