Allow modules loaded via require() to use script-relative paths

premake5.lua

@@ -36,6 +36,7 @@
 
 		excludes
 		{
+			"src/host/lua-5.1.4/src/lauxlib.c",
 			"src/host/lua-5.1.4/src/lua.c",
 			"src/host/lua-5.1.4/src/luac.c",
 			"src/host/lua-5.1.4/src/print.c",

src/base/globals.lua

@@ -1,11 +1,11 @@
 --
 -- globals.lua
 -- Replacements and extensions to Lua's global functions.
--- Copyright (c) 2002-2013 Jason Perkins and the Premake project
+-- Copyright (c) 2002-2014 Jason Perkins and the Premake project
 --
 
 
---
+---
 -- Helper for the dofile() and include() function: locate a script on the
 -- standard search paths of: the /scripts argument provided on the command
 -- line, then the PREMAKE_PATH environment variable.
@@ -15,12 +15,10 @@
 --    is the one that will be returned.
 -- @return
 --    The path to file if found, or nil if not.
---
+---
 
 	local function locate(...)
-		for i = 1, select("#",...) do
-			local fname = select(i,...)
-
+		local function find(fname)
 			-- is this a direct path to a file?
 			if os.isfile(fname) then
 				return fname
@@ -32,41 +30,33 @@
 				return path.join(dir, fname)
 			end
 		end
+
+		for i = 1, select("#",...) do
+			local fname = select(i, ...)
+			local result = find(fname)
+			if not result then
+				result = find(fname .. ".lua")
+			end
+			if result then
+				return result
+			end
+		end
 	end
 
 
---
--- A replacement for Lua's built-in dofile() function, this one sets the
--- current working directory to the script's location, enabling script-relative
--- referencing of other files and resources.
---
+
+---
+-- A replacement for Lua's built-in dofile() function that knows how to
+-- search for script files. Note that I've also modified luaL_loadfile()
+-- in src/host/lua_auxlib.c to set the _SCRIPT variable and adjust the
+-- working directory.
+---
 
 	local builtin_dofile = dofile
 
 	function dofile(fname)
-		-- remember the current working directory and file; I'll restore it shortly
-		local oldcwd = os.getcwd()
-		local oldfile = _SCRIPT
-
-		-- find it; if I can't just continue with the name and let the
-		-- built-in dofile() handle reporting the error as it will
 		fname = locate(fname) or fname
-
-		-- use the absolute path to the script file, to avoid any file name
-		-- ambiguity if an error should arise
-		_SCRIPT = path.getabsolute(fname)
-
-		-- switch the working directory to the new script location
-		local newcwd = path.getdirectory(_SCRIPT)
-		os.chdir(newcwd)
-
-		-- run the chunk. How can I catch variable return values?
-		local a, b, c, d, e, f = builtin_dofile(_SCRIPT)
-
-		-- restore the previous working directory when done
-		_SCRIPT = oldfile
-		os.chdir(oldcwd)
-		return a, b, c, d, e, f
+		return builtin_dofile(fname)
 	end
 
 
@@ -97,24 +87,23 @@
 
 
 
---
+---
 -- Load and run an external script file, with a bit of extra logic to make
 -- including projects easier. if "path" is a directory, will look for
 -- path/premake5.lua. And each file is tracked, and loaded only once.
 --
+-- @param fname
+--    The name of the directory or file to include. If a directory, will
+--    automatically include the contained premake5.lua or premake4.lua
+--    script at that lcoation.
+---
 
 	io._includedFiles = {}
 
 	function include(fname)
-		local found = locate(fname)
-		if not found then
-			found = locate(path.join(fname, "premake5.lua"))
-		end
-		if not found then
-			found = locate(path.join(fname, "premake4.lua"))
-		end
+		local found = locate(fname, path.join(fname, "premake5.lua"), path.join(fname, "premake4.lua"))
 
-		-- but only load each file once
+		-- only include each file once
 		fname = path.getabsolute(found or fname)
 		if not io._includedFiles[fname] then
 			io._includedFiles[fname] = true

src/host/lua-5.1.4/src/lauxlib.c

@@ -574,7 +574,7 @@ LUALIB_API int luaL_loadfile (lua_State *L, const char *filename) {
     lf.f = freopen(filename, "rb", lf.f);  /* reopen in binary mode */
     if (lf.f == NULL) return errfile(L, "reopen", fnameindex);
     /* skip eventual `#!...' */
-   while ((c = getc(lf.f)) != EOF && c != LUA_SIGNATURE[0]) ;
+   while ((c = getc(lf.f)) != EOF && c != LUA_SIGNATURE[0]) {};
     lf.extraline = 0;
   }
   ungetc(c, lf.f);

src/host/lua_auxlib.c

@@ -0,0 +1,91 @@
+/**
+ * \file   lua_auxlib.c
+ * \brief  Modifications and extensions to Lua's library functions.
+ * \author Copyright (c) 2014 Jason Perkins and the Premake project
+ */
+
+#include "premake.h"
+
+
+#define luaL_loadfile  original_luaL_loadfile
+
+#include "lua-5.1.4/src/lauxlib.c"
+
+#undef luaL_loadfile
+
+
+/**
+ * Execute a chunk of code previous loaded by my customized version of
+ * luaL_loadfile(), below. Sets the _SCRIPT global variable to the
+ * absolute path of the loaded chunk, and makes its enclosing directory
+ * current so that relative path references to other files or scripts
+ * can be used.
+ */
+
+static int chunk_wrapper(lua_State* L)
+{
+	char cwd[PATH_MAX];
+	char script[PATH_MAX];
+	const char* filename;
+	char* ptr;
+	int i, args;
+
+	args = lua_gettop(L);
+
+	/* Remember the current _SCRIPT and working directory so I can
+	 * restore them after the script chunk has been run. */
+
+	do_getcwd(cwd, PATH_MAX);
+	lua_getglobal(L, "_SCRIPT");
+
+	/* Set the new _SCRIPT variable... */
+
+	filename = lua_tostring(L, lua_upvalueindex(2));
+	do_getabsolute(script, filename, NULL);
+	lua_pushstring(L, script);
+	lua_setglobal(L, "_SCRIPT");
+
+	/* ...and make it's containing directory current */
+
+	ptr = strrchr(script, '/');
+	if (ptr) *ptr = '\0';
+	do_chdir(script);
+	if (ptr) *ptr = '/';
+
+	/* Move the function's arguments to the top of the stack and
+	 * execute the function created by luaL_loadfile() */
+
+	lua_pushvalue(L, lua_upvalueindex(1));
+	for (i = 1; i <= args; ++i) {
+		lua_pushvalue(L, i);
+	}
+
+	lua_call(L, args, LUA_MULTRET);
+
+	/* Finally, restore the previous _SCRIPT variable and working directory
+	 * before returning control to the previously executing script. */
+
+	do_chdir(cwd);
+	lua_pushvalue(L, args + 1);
+	lua_setglobal(L, "_SCRIPT");
+
+	return lua_gettop(L) - args - 1;
+}
+
+
+
+/**
+ * Extend the default implementation of luaL_loadfile() to call my chunk
+ * wrapper, above, before executing any scripts loaded from a file.
+ */
+
+LUALIB_API int luaL_loadfile (lua_State* L, const char* filename)
+{
+	int z = original_luaL_loadfile(L, filename);
+	if (z == 0) {
+		lua_pushstring(L, filename);
+		lua_pushcclosure(L, chunk_wrapper, 2);
+	}
+
+	return z;
+}

src/host/os_chdir.c

@@ -1,16 +1,15 @@
 /**
  * \file   os_chdir.c
  * \brief  Change the current working directory.
- * \author Copyright (c) 2002-2008 Jason Perkins and the Premake project
+ * \author Copyright (c) 2002-2014 Jason Perkins and the Premake project
  */
 
 #include "premake.h"
 
 
-int os_chdir(lua_State* L)
+int do_chdir(const char* path)
 {
 	int z;
-	const char* path = luaL_checkstring(L, 1);
 
 #if PLATFORM_WINDOWS
 	z = SetCurrentDirectory(path);
@@ -18,6 +17,16 @@ int os_chdir(lua_State* L)
 	z = !chdir(path);
 #endif
 
+	return z;
+}
+
+
+
+int os_chdir(lua_State* L)
+{
+	const char* path = luaL_checkstring(L, 1);
+
+	int z = do_chdir(path);
 	if (!z)
 	{
 		lua_pushnil(L);

src/host/premake.h

@@ -61,6 +61,7 @@
 
 
 /* Bootstrapping helper functions */
+int do_chdir(const char* path);
 unsigned long do_hash(const char* str, int seed);
 void do_getabsolute(char* result, const char* value, const char* relative_to);
 int do_getcwd(char* buffer, size_t size);