Getting rid of irrelevant features : Source mapping, js modern/flatten

Javascript is one of the more flexible targets in the Haxe language.
There's actually two different ways you can generate javascript source.
(Without going into too many details, one is for legacy purposes).  In
addition, there's also the ability to flatten packages, and to generate
source maps for certain browser debugging purposes.

None of those features are appropriate for Lua, and they constituted a
fair amount of code in the original genjs source. So, it's a good idea
to get rid of them early and focus on what matters.

genlua.ml

@@ -26,26 +26,10 @@ open Common
 
 type pos = Ast.pos
 
-type sourcemap = {
-	sources : (string) DynArray.t;
-	sources_hash : (string, int) Hashtbl.t;
-	mappings : Buffer.t;
-
-	mutable source_last_line : int;
-	mutable source_last_col : int;
-	mutable source_last_file : int;
-	mutable print_comma : bool;
-	mutable output_last_col : int;
-	mutable output_current_col : int;
-}
-
 type ctx = {
 	com : Common.context;
 	buf : Buffer.t;
 	packages : (string list,unit) Hashtbl.t;
-	smap : sourcemap;
-	js_modern : bool;
-	js_flatten : bool;
 	mutable current : tclass;
 	mutable statics : (tclass * string * texpr) list;
 	mutable inits : texpr list;
@@ -64,9 +48,7 @@ type object_store = {
 	mutable os_fields : object_store list;
 }
 
-let get_exposed ctx path meta =
-	if not ctx.js_modern then []
-	else try
+let get_exposed ctx path meta = try
 		let (_, args, pos) = Meta.get Meta.Expose meta in
 		(match args with
 			| [ EConst (String s), _ ] -> [s]
@@ -84,7 +66,7 @@ let flat_path (p,s) =
 	| [] -> escape s
 	| _ -> String.concat "_" (List.map escape p) ^ "_" ^ (escape s)
 
-let s_path ctx = if ctx.js_flatten then flat_path else dot_path
+let s_path ctx = dot_path
 
 let kwds =
 	let h = Hashtbl.create 0 in
@@ -136,129 +118,24 @@ let static_field s =
 let has_feature ctx = Common.has_feature ctx.com
 let add_feature ctx = Common.add_feature ctx.com
 
-let handle_newlines ctx str =
-	if ctx.com.debug then
-		let rec loop from =
-			try begin
-				let next = String.index_from str from '\n' + 1 in
-				Buffer.add_char ctx.smap.mappings ';';
-				ctx.smap.output_last_col <- 0;
-				ctx.smap.print_comma <- false;
-				loop next
-			end with Not_found ->
-				ctx.smap.output_current_col <- String.length str - from
-		in
-		loop 0
-	else ()
-
 let spr ctx s =
 	ctx.separator <- false;
-	handle_newlines ctx s;
 	Buffer.add_string ctx.buf s
 
 let print ctx =
 	ctx.separator <- false;
 	Printf.kprintf (fun s -> begin
-		handle_newlines ctx s;
 		Buffer.add_string ctx.buf s
 	end)
 
 let unsupported p = error "This expression cannot be compiled to Javascript" p
 
-let add_mapping ctx e =
-	if not ctx.com.debug || e.epos.pmin < 0 then () else
-	let pos = e.epos in
-	let smap = ctx.smap in
-	let file = try
-		Hashtbl.find smap.sources_hash pos.pfile
-	with Not_found ->
-		let length = DynArray.length smap.sources in
-		Hashtbl.replace smap.sources_hash pos.pfile length;
-		DynArray.add smap.sources pos.pfile;
-		length
-	in
-	let line, col = Lexer.find_pos pos in
-	let line = line - 1 in
-	let col = col - 1 in
-	if smap.source_last_file != file || smap.source_last_line != line || smap.source_last_col != col then begin
-		if smap.print_comma then
-			Buffer.add_char smap.mappings ','
-		else
-			smap.print_comma <- true;
-
-		let base64_vlq number =
-			let encode_digit digit =
-				let chars = [|
-					'A';'B';'C';'D';'E';'F';'G';'H';'I';'J';'K';'L';'M';'N';'O';'P';
-					'Q';'R';'S';'T';'U';'V';'W';'X';'Y';'Z';'a';'b';'c';'d';'e';'f';
-					'g';'h';'i';'j';'k';'l';'m';'n';'o';'p';'q';'r';'s';'t';'u';'v';
-					'w';'x';'y';'z';'0';'1';'2';'3';'4';'5';'6';'7';'8';'9';'+';'/'
-				|] in
-				Array.unsafe_get chars digit
-			in
-			let to_vlq number =
-				if number < 0 then
-					((-number) lsl 1) + 1
-				else
-					number lsl 1
-			in
-			let rec loop vlq =
-				let shift = 5 in
-				let base = 1 lsl shift in
-				let mask = base - 1 in
-				let continuation_bit = base in
-				let digit = vlq land mask in
-				let next = vlq asr shift in
-				Buffer.add_char smap.mappings (encode_digit (
-					if next > 0 then digit lor continuation_bit else digit));
-				if next > 0 then loop next else ()
-			in
-			loop (to_vlq number)
-		in
-
-		base64_vlq (smap.output_current_col - smap.output_last_col);
-		base64_vlq (file - smap.source_last_file);
-		base64_vlq (line - smap.source_last_line);
-		base64_vlq (col - smap.source_last_col);
-
-		smap.source_last_file <- file;
-		smap.source_last_line <- line;
-		smap.source_last_col <- col;
-		smap.output_last_col <- smap.output_current_col
-	end
-
 let basename path =
 	try
 		let idx = String.rindex path '/' in
 		String.sub path (idx + 1) (String.length path - idx - 1)
 	with Not_found -> path
 
-let write_mappings ctx =
-	let basefile = basename ctx.com.file in
-	print ctx "\n//# sourceMappingURL=%s.map" basefile;
-	let channel = open_out_bin (ctx.com.file ^ ".map") in
-	let sources = DynArray.to_list ctx.smap.sources in
-	let to_url file =
-		ExtString.String.map (fun c -> if c == '\\' then '/' else c) (Common.get_full_path file)
-	in
-	output_string channel "{\n";
-	output_string channel "\"version\":3,\n";
-	output_string channel ("\"file\":\"" ^ (String.concat "\\\\" (ExtString.String.nsplit basefile "\\")) ^ "\",\n");
-	output_string channel ("\"sourceRoot\":\"file:///\",\n");
-	output_string channel ("\"sources\":[" ^
-		(String.concat "," (List.map (fun s -> "\"" ^ to_url s ^ "\"") sources)) ^
-		"],\n");
-	if Common.defined ctx.com Define.SourceMapContent then begin
-		output_string channel ("\"sourcesContent\":[" ^
-			(String.concat "," (List.map (fun s -> try "\"" ^ Ast.s_escape (Std.input_file ~bin:true s) ^ "\"" with _ -> "null") sources)) ^
-			"],\n");
-	end;
-	output_string channel "\"names\":[],\n";
-	output_string channel "\"mappings\":\"";
-	Buffer.output_buffer channel ctx.smap.mappings;
-	output_string channel "\"\n";
-	output_string channel "}";
-	close_out channel
 
 let newline ctx =
 	match Buffer.nth ctx.buf (Buffer.length ctx.buf - 1) with
@@ -468,7 +345,6 @@ let rec gen_call ctx e el in_value =
 		spr ctx ")"
 
 and gen_expr ctx e =
-	add_mapping ctx e;
 	match e.eexpr with
 	| TConst c -> gen_constant ctx e.epos c
 	| TLocal v -> spr ctx (ident v.v_name)
@@ -778,7 +654,6 @@ and gen_block_element ?(after=false) ctx e =
 		if after then newline ctx
 
 and gen_value ctx e =
-	add_mapping ctx e;
 	let assign e =
 		mk (TBinop (Ast.OpAssign,
 			mk (TLocal (match ctx.in_value with None -> assert false | Some v -> v)) t_dynamic e.epos,
@@ -898,17 +773,10 @@ let generate_package_create ctx (p,_) =
 		| p :: l ->
 			Hashtbl.add ctx.packages (p :: acc) ();
 			(match acc with
-			| [] ->
-				if ctx.js_modern then
-					print ctx "var %s = {}" p
-				else
-					print ctx "var %s = %s || {}" p p
+			| [] -> print ctx "var %s = {}" p
 			| _ ->
 				let p = String.concat "." (List.rev acc) ^ (field p) in
-				if ctx.js_modern then
-					print ctx "%s = {}" p
-				else
-					print ctx "if(!%s) %s = {}" p p
+                print ctx "%s = {}" p
 			);
 			ctx.separator <- true;
 			newline ctx;
@@ -985,14 +853,8 @@ let generate_class ctx c =
 	| _ -> ());
 	let p = s_path ctx c.cl_path in
 	let hxClasses = has_feature ctx "Type.resolveClass" in
-	if ctx.js_flatten then
-		print ctx "var "
-	else
-		generate_package_create ctx c.cl_path;
-	if ctx.js_modern || not hxClasses then
-		print ctx "%s = " p
-	else
-		print ctx "%s = $hxClasses[\"%s\"] = " p (dot_path c.cl_path);
+    generate_package_create ctx c.cl_path;
+    print ctx "%s = " p;
 	(match (get_exposed ctx (dot_path c.cl_path) c.cl_meta) with [s] -> print ctx "$hx_exports.%s = " s | _ -> ());
 	(match c.cl_kind with
 		| KAbstractImpl _ ->
@@ -1004,7 +866,7 @@ let generate_class ctx c =
 			| _ -> (print ctx "function() { }"); ctx.separator <- true)
 	);
 	newline ctx;
-	if ctx.js_modern && hxClasses then begin
+	if hxClasses then begin
 		print ctx "$hxClasses[\"%s\"] = %s" (dot_path c.cl_path) p;
 		newline ctx;
 	end;
@@ -1072,10 +934,7 @@ let generate_class ctx c =
 let generate_enum ctx e =
 	let p = s_path ctx e.e_path in
 	let ename = List.map (fun s -> Printf.sprintf "\"%s\"" (Ast.s_escape s)) (fst e.e_path @ [snd e.e_path]) in
-	if ctx.js_flatten then
-		print ctx "var "
-	else
-		generate_package_create ctx e.e_path;
+    generate_package_create ctx e.e_path;
 	print ctx "%s = " p;
 	if has_feature ctx "Type.resolveEnum" then print ctx "$hxClasses[\"%s\"] = " (dot_path e.e_path);
 	print ctx "{";
@@ -1131,10 +990,7 @@ let generate_require ctx c =
 	let _, args, mp = Meta.get Meta.JsRequire c.cl_meta in
 	let p = (s_path ctx c.cl_path) in
 
-	if ctx.js_flatten then
-		spr ctx "var "
-	else
-		generate_package_create ctx c.cl_path;
+    generate_package_create ctx c.cl_path;
 
 	(match args with
 	| [(EConst(String(module_name)),_)] ->
@@ -1162,7 +1018,7 @@ let generate_type ctx = function
 			generate_class ctx c
 		else if (Meta.has Meta.JsRequire c.cl_meta) && (Meta.has Meta.ReallyUsed c.cl_meta) then
 			generate_require ctx c
-		else if not ctx.js_flatten && Meta.has Meta.InitPackage c.cl_meta then
+		else if Meta.has Meta.InitPackage c.cl_meta then
 			(match c.cl_path with
 			| ([],_) -> ()
 			| _ -> generate_package_create ctx c.cl_path)
@@ -1179,19 +1035,6 @@ let alloc_ctx com =
 		com = com;
 		buf = Buffer.create 16000;
 		packages = Hashtbl.create 0;
-		smap = {
-			source_last_line = 0;
-			source_last_col = 0;
-			source_last_file = 0;
-			print_comma = false;
-			output_last_col = 0;
-			output_current_col = 0;
-			sources = DynArray.create();
-			sources_hash = Hashtbl.create 0;
-			mappings = Buffer.create 16;
-		};
-		js_modern = not (Common.defined com Define.JsClassic);
-		js_flatten = Common.defined com Define.JsFlatten;
 		statics = [];
 		inits = [];
 		current = null_class;
@@ -1285,7 +1128,7 @@ let generate com =
 		closureArgs
 	in
 
-	if ctx.js_modern then begin
+	begin
 		(* Additional ES5 strict mode keywords. *)
 		List.iter (fun s -> Hashtbl.replace kwds s ()) [ "arguments"; "eval" ];
 
@@ -1308,13 +1151,9 @@ let generate com =
 		List.iter (fun f -> print_obj f "$hx_exports") exposedObject.os_fields;
 	end;
 
-	(* If ctx.js_modern, console is defined in closureArgs. *)
-	if (not ctx.js_modern) && (not (Common.defined com Define.JsEs5)) then
-		spr ctx "var console = Function(\"return typeof console != 'undefined' ? console : {log:function(){}}\")();\n";
-
 	(* TODO: fix $estr *)
 	let vars = [] in
-	let vars = (if has_feature ctx "Type.resolveClass" || has_feature ctx "Type.resolveEnum" then ("$hxClasses = " ^ (if ctx.js_modern then "{}" else "$hxClasses || {}")) :: vars else vars) in
+    let vars = (if has_feature ctx "Type.resolveClass" || has_feature ctx "Type.resolveEnum" then ("$hxClasses = " ^ "{}") :: vars else vars) in
 	let vars = if has_feature ctx "may_print_enum"
 		then ("$estr = function() { return " ^ (ctx.type_accessor (TClassDecl { null_class with cl_path = ["js"],"Boot" })) ^ ".__string_rec(this,''); }") :: vars
 		else vars in
@@ -1367,7 +1206,7 @@ let generate com =
 	(match com.main with
 	| None -> ()
 	| Some e -> gen_expr ctx e; newline ctx);
-	if ctx.js_modern then begin
+	begin
 		print ctx "})(%s)" (String.concat ", " (List.map snd closureArgs));
 		newline ctx;
 		if (anyExposed && (Common.defined com Define.ShallowExpose)) then (
@@ -1383,7 +1222,6 @@ let generate com =
 			) !toplevelExposed
 		);
 	end;
-	if com.debug then write_mappings ctx else (try Sys.remove (com.file ^ ".map") with _ -> ());
 	let ch = open_out_bin com.file in
 	output_string ch (Buffer.contents ctx.buf);
 	close_out ch);