re-write of zap.Router, fix #83

examples/simple_router/simple_router.zig

@@ -82,17 +82,17 @@ pub fn main() !void {
 
     var somePackage = SomePackage.init(allocator, 1, 2);
 
-    try simpleRouter.handle_func("/", on_request_verbose);
+    try simpleRouter.handle_func_unbound("/", on_request_verbose);
 
-    try simpleRouter.handle_func("/geta", zap.RequestHandler(&somePackage, SomePackage.getA));
+    try simpleRouter.handle_func("/geta", &somePackage, &SomePackage.getA);
 
-    try simpleRouter.handle_func("/getb", zap.RequestHandler(&somePackage, SomePackage.getB));
+    try simpleRouter.handle_func("/getb", &somePackage, &SomePackage.getB);
 
-    try simpleRouter.handle_func("/inca", zap.RequestHandler(&somePackage, SomePackage.incrementA));
+    try simpleRouter.handle_func("/inca", &somePackage, &SomePackage.incrementA);
 
     var listener = zap.HttpListener.init(.{
         .port = 3000,
-        .on_request = zap.RequestHandler(&simpleRouter, &zap.Router.serve),
+        .on_request = simpleRouter.on_request_handler(),
         .log = true,
         .max_clients = 100000,
     });

src/router.zig

@@ -2,6 +2,8 @@ const std = @import("std");
 const zap = @import("zap.zig");
 
 const Allocator = std.mem.Allocator;
+
+/// Errors returnable by init()
 const RouterError = error{
     AlreadyExists,
     EmptyPath,
@@ -9,46 +11,101 @@ const RouterError = error{
 
 const Self = @This();
 
+/// This is a singleton
+var _instance: *Self = undefined;
+
+/// Options to pass to init()
 pub const Options = struct {
+    /// an optional zap request function for 404 not found case
     not_found: ?zap.HttpRequestFn = null,
 };
 
-routes: std.StringHashMap(zap.HttpRequestFn),
+const CallbackTag = enum { bound, unbound };
+const BoundHandler = *fn (*const anyopaque, zap.Request) void;
+const Callback = union(CallbackTag) {
+    bound: struct { instance: usize, handler: usize },
+    unbound: zap.HttpRequestFn,
+};
+
+routes: std.StringHashMap(Callback),
 not_found: ?zap.HttpRequestFn,
 
+/// Create a new Router
 pub fn init(allocator: Allocator, options: Options) Self {
     return .{
-        .routes = std.StringHashMap(zap.HttpRequestFn).init(allocator),
+        .routes = std.StringHashMap(Callback).init(allocator),
 
         .not_found = options.not_found,
     };
 }
 
+/// Deinit the router
 pub fn deinit(self: *Self) void {
     self.routes.deinit();
 }
 
-pub fn handle_func(self: *Self, path: []const u8, h: zap.HttpRequestFn) !void {
+/// Call this to add a route with an unbound handler: a handler that is not member of a struct.
+pub fn handle_func_unbound(self: *Self, path: []const u8, h: zap.HttpRequestFn) !void {
     if (path.len == 0) {
         return RouterError.EmptyPath;
     }
 
-    const route = self.routes.get(path);
-
-    if (route != null) {
+    if (self.routes.contains(path)) {
         return RouterError.AlreadyExists;
     }
 
-    try self.routes.put(path, h);
+    try self.routes.put(path, Callback{ .unbound = h });
 }
 
-pub fn serve(self: *Self, r: zap.Request) void {
-    const path = if (r.path) |p| p else "/";
+/// Call this to add a route with a handler that is bound to an instance of a struct.
+/// Example:
+///
+/// ```zig
+/// const HandlerType = struct {
+///     pub fn getA(self: *HandlerType, r: zap.Request) void {
+///         _ = self;
+///         r.sendBody("hello\n\n") catch return;
+///     }
+/// }
+/// var handler_instance = HandlerType{};
+///
+/// my_router.handle_func("/getA", &handler_instance, HandlerType.getA);
+/// ```
+pub fn handle_func(self: *Self, path: []const u8, instance: *anyopaque, handler: anytype) !void {
+    // TODO: assert type of instance has handler
 
-    const route = self.routes.get(path);
+    if (path.len == 0) {
+        return RouterError.EmptyPath;
+    }
 
-    if (route) |handler| {
-        handler(r);
+    if (self.routes.contains(path)) {
+        return RouterError.AlreadyExists;
+    }
+
+    try self.routes.put(path, Callback{ .bound = .{
+        .instance = @intFromPtr(instance),
+        .handler = @intFromPtr(handler),
+    } });
+}
+
+/// Get the zap request handler function needed for a listener
+pub fn on_request_handler(self: *Self) zap.HttpRequestFn {
+    _instance = self;
+    return zap_on_request;
+}
+
+fn zap_on_request(r: zap.Request) void {
+    return serve(_instance, r);
+}
+
+fn serve(self: *Self, r: zap.Request) void {
+    const path = r.path orelse "/";
+
+    if (self.routes.get(path)) |routeInfo| {
+        switch (routeInfo) {
+            .bound => |b| @call(.auto, @as(BoundHandler, @ptrFromInt(b.handler)), .{ @as(*anyopaque, @ptrFromInt(b.instance)), r }),
+            .unbound => |h| h(r),
+        }
     } else if (self.not_found) |handler| {
         // not found handler
         handler(r);

src/util.zig

@@ -2,23 +2,6 @@ const std = @import("std");
 const fio = @import("fio.zig");
 const zap = @import("zap.zig");
 
-/// capture self for RequestFn signature support
-pub inline fn RequestHandler(self: anytype, func: *const fn (@TypeOf(self), zap.Request) void) *const fn (zap.Request) void {
-    return (opaque {
-        var hidden_self: @TypeOf(self) = undefined;
-        var hidden_func: *const fn (@TypeOf(self), zap.Request) void = undefined;
-        pub fn init(h_self: @TypeOf(self), h_func: *const fn (@TypeOf(self), zap.Request) void) *const @TypeOf(run) {
-            hidden_self = h_self;
-            hidden_func = h_func;
-            return &run;
-        }
-
-        fn run(req: zap.Request) void {
-            hidden_func(hidden_self, req);
-        }
-    }).init(self, func);
-}
-
 /// Used internally: convert a FIO object into its string representation.
 /// note: since this is called from within request functions, we don't make
 /// copies. Also, we return temp memory from fio. -> don't hold on to it outside