Re-add love.filesystem.exists.

It's still useful sometimes because it's a bit cheaper than getInfo.

src/modules/filesystem/Filesystem.h

@@ -216,6 +216,11 @@ public:
 	 **/
 	virtual std::string getRealDirectory(const char *filename) const = 0;
 
+	/**
+	 * Gets whether anything exists at the specified path.
+	 **/
+	virtual bool exists(const char *filepath) const = 0;
+
 	/**
 	 * Gets information about the item at the specified filepath. Returns false
 	 * if nothing exists at the path.

src/modules/filesystem/physfs/Filesystem.cpp

@@ -738,6 +738,14 @@ std::string Filesystem::getRealDirectory(const char *filename) const
 	return std::string(dir);
 }
 
+bool Filesystem::exists(const char *filepath) const
+{
+	if (!PHYSFS_isInit())
+		return false;
+
+	return PHYSFS_exists(filepath) != 0;
+}
+
 bool Filesystem::getInfo(const char *filepath, Info &info) const
 {
 	if (!PHYSFS_isInit())

src/modules/filesystem/physfs/Filesystem.h

@@ -82,6 +82,7 @@ public:
 
 	std::string getRealDirectory(const char *filename) const override;
 
+	bool exists(const char *filepath) const override;
 	bool getInfo(const char *filepath, Info &info) const override;
 
 	bool createDirectory(const char *dir) override;

src/modules/filesystem/wrap_Filesystem.cpp

@@ -502,6 +502,13 @@ int w_getExecutablePath(lua_State *L)
 	return 1;
 }
 
+int w_exists(lua_State *L)
+{
+	const char *path = luaL_checkstring(L, 1);
+	luax_pushboolean(L, instance()->exists(path));
+	return 1;
+}
+
 int w_getInfo(lua_State *L)
 {
 	const char *filepath = luaL_checkstring(L, 1);
@@ -1000,6 +1007,7 @@ static const luaL_Reg functions[] =
 	{ "getDirectoryItems", w_getDirectoryItems },
 	{ "lines", w_lines },
 	{ "load", w_load },
+	{ "exists", w_exists },
 	{ "getInfo", w_getInfo },
 	{ "setSymlinksEnabled", w_setSymlinksEnabled },
 	{ "areSymlinksEnabled", w_areSymlinksEnabled },