Fix support for ODB custom backends.

1 files changed, 236 insertions, 0 deletions

diff --git a/src/odb_backend.nobj.lua b/src/odb_backend.nobj.lua
new file mode 100644
index 0000000..4e8d9a5
--- /dev/null
+++ b/src/odb_backend.nobj.lua
@@ -0,0 +1,236 @@
+-- Copyright (c) 2010 by Robert G. Jakabosky <bobby@sharedrealm.com>
+--
+-- Permission is hereby granted, free of charge, to any person obtaining a copy
+-- of this software and associated documentation files (the "Software"), to deal
+-- in the Software without restriction, including without limitation the rights
+-- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+-- copies of the Software, and to permit persons to whom the Software is
+-- furnished to do so, subject to the following conditions:
+--
+-- The above copyright notice and this permission notice shall be included in
+-- all copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+-- THE SOFTWARE.
+
+object "ODBBackend" {
+	c_source [[
+#include <git2/odb_backend.h>
+
+typedef struct ODBBackend {
+	git_odb_backend backend;
+	lua_State *L;
+	int read;
+	int read_prefix;
+	int read_header;
+	int write;
+	int exists;
+	int free;
+	int ref_count;
+} ODBBackend;
+
+static void ODBBackend_ref(ODBBackend *backend) {
+	backend->ref_count++;
+}
+
+static void ODBBackend_unref(ODBBackend *backend) {
+	lua_State *L = backend->L;
+	if((--backend->ref_count) == 0) {
+		luaL_unref(L, LUA_REGISTRYINDEX, backend->read);
+		luaL_unref(L, LUA_REGISTRYINDEX, backend->read_prefix);
+		luaL_unref(L, LUA_REGISTRYINDEX, backend->read_header);
+		luaL_unref(L, LUA_REGISTRYINDEX, backend->write);
+		luaL_unref(L, LUA_REGISTRYINDEX, backend->exists);
+		luaL_unref(L, LUA_REGISTRYINDEX, backend->free);
+		free(backend);
+	}
+}
+
+static int odb_backend_read_cb(void **data_p, size_t *len_p, git_otype *type_p, git_odb_backend *backend, const git_oid *oid)
+{
+	ODBBackend *lua_backend = (ODBBackend *)backend;
+	lua_State *L = lua_backend->L;
+	const char *ldata;
+	size_t len;
+	int err;
+
+	/* get Lua callback function. */
+	lua_rawgeti(L, LUA_REGISTRYINDEX, lua_backend->read);
+
+	obj_type_OID_push(L, *((OID *)oid));
+	/* call Lua function. */
+	lua_call(L, 1, 2);
+	ldata = lua_tolstring(L, -2, &len);
+	if(ldata) {
+		char *data;
+		/* parse otype value. */
+		int arg_type = lua_type(L, -1);
+		if(arg_type == LUA_TNUMBER) {
+			*type_p = lua_tointeger(L, -1);
+		} else if(arg_type == LUA_TSTRING) {
+			*type_p = git_object_string2type(lua_tostring(L, -1));
+		}
+		*len_p = len;
+		/* allocate buffer for data. */
+		data = malloc(len);
+		*data_p = data;
+		if(data == NULL) {
+			return GIT_ENOMEM;
+		}
+		/* copy data. */
+		memcpy(data, ldata, len);
+		err = GIT_SUCCESS;
+	} else if(lua_isnil(L, -2)) {
+		*data_p = NULL;
+		/* backend returned an error. */
+		err = lua_tointeger(L, -1);
+	} else {
+		*data_p = NULL;
+		/* bad return value from lua backend. */
+		err = GIT_EOBJTYPE;
+	}
+
+	return err;
+}
+
+static int odb_backend_read_prefix_cb(git_oid *out_oid, void **data_p, size_t *len_p, git_otype *type_p, git_odb_backend *backend, const git_oid *short_oid, unsigned int len)
+{
+	*data_p = NULL;
+	if(len >= GIT_OID_HEXSZ) {
+		int rc = odb_backend_read_cb(data_p, len_p, type_p, backend, short_oid);
+		if(rc == GIT_SUCCESS) {
+			git_oid_cpy(out_oid, short_oid);
+		}
+		return rc;
+	}
+	return GIT_ENOTIMPLEMENTED;
+}
+
+static int odb_backend_read_header_cb(size_t *len_p, git_otype *type_p, git_odb_backend *backend, const git_oid *oid)
+{
+	ODBBackend *lua_backend = (ODBBackend *)backend;
+	lua_State *L = lua_backend->L;
+	int err;
+	int arg_type;
+
+	/* get Lua callback function. */
+	lua_rawgeti(L, LUA_REGISTRYINDEX, lua_backend->read_header);
+
+	obj_type_OID_push(L, *((OID *)oid));
+	/* call Lua function. */
+	lua_call(L, 1, 2);
+
+	arg_type = lua_type(L, -2);
+	if(arg_type == LUA_TSTRING || arg_type == LUA_TNUMBER) {
+		/* parse data length. */
+		*len_p = lua_tonumber(L, -2);
+		/* parse otype value. */
+		lua_type(L, -1);
+		if(arg_type == LUA_TNUMBER) {
+			*type_p = lua_tointeger(L, -1);
+		} else if(arg_type == LUA_TSTRING) {
+			*type_p = git_object_string2type(lua_tostring(L, -1));
+		}
+		err = GIT_SUCCESS;
+	} else if(arg_type == LUA_TNIL) {
+		/* backend returned an error. */
+		err = lua_tointeger(L, -1);
+	} else {
+		/* bad return value from lua backend. */
+		err = GIT_EOBJTYPE;
+	}
+
+	return err;
+}
+
+static int odb_backend_write_cb(git_oid *oid, git_odb_backend *backend, const void *data, size_t len, git_otype type)
+{
+	ODBBackend *lua_backend = (ODBBackend *)backend;
+	lua_State *L = lua_backend->L;
+	int err;
+
+	/* get Lua callback function. */
+	lua_rawgeti(L, LUA_REGISTRYINDEX, lua_backend->write);
+
+	/* push data onto stack. */
+	lua_pushlstring(L, data, len);
+	/* push otype */
+	lua_pushstring(L, git_object_type2string(type));
+
+	/* call Lua function. */
+	lua_call(L, 2, 2);
+	if(!lua_isnil(L, -2)) {
+		*oid = obj_type_OID_check(L,-2);
+		err = GIT_SUCCESS;
+	} else {
+		err = lua_tointeger(L, -1);
+	}
+
+	return err;
+}
+
+static int odb_backend_exists_cb(git_odb_backend *backend, const git_oid *oid)
+{
+	ODBBackend *lua_backend = (ODBBackend *)backend;
+	lua_State *L = lua_backend->L;
+
+	/* get Lua callback function. */
+	lua_rawgeti(L, LUA_REGISTRYINDEX, lua_backend->exists);
+
+	obj_type_OID_push(L, *((OID *)oid));
+	/* call Lua function. */
+	lua_call(L, 1, 1);
+	return lua_tointeger(L, -1);
+}
+
+static void odb_backend_free_cb(git_odb_backend *backend)
+{
+	ODBBackend *lua_backend = (ODBBackend *)backend;
+	lua_State *L = lua_backend->L;
+
+	/* get Lua callback function. */
+	lua_rawgeti(L, LUA_REGISTRYINDEX, lua_backend->free);
+
+	/* call Lua function. */
+	lua_call(L, 0, 0);
+
+	ODBBackend_unref(lua_backend);
+}
+
+]],
+	constructor {
+		var_in{"lua_State *", "L"},
+		c_source [[
+	luaL_checktype(L, 1, LUA_TTABLE);
+	lua_settop(L, 1);
+	/* create backend object. */
+	${this} = calloc(1, sizeof(ODBBackend));
+	${this}->ref_count = 1;
+	${this}->L = L;
+	/* get each callback from table. */
+#define REF_CB(_name) \
+	lua_getfield(L, 1, "on_" #_name); \
+	${this}->_name = luaL_ref(L, LUA_REGISTRYINDEX); \
+	${this}->backend._name = odb_backend_ ## _name ## _cb;
+
+	REF_CB(read)
+	REF_CB(read_prefix)
+	REF_CB(read_header)
+	REF_CB(write)
+	REF_CB(exists)
+	REF_CB(free)
+#undef REF_CB
+]]
+	},
+	destructor {
+		c_source [[
+	ODBBackend_unref(${this});
+]]
+	},
+}
+