Add basic implementation for Class (#21)

* Class init

* Basic implementation for Class

Author: richerfu

examples/basic/src/class.zig

@@ -0,0 +1,8 @@
+const napi = @import("napi");
+
+const Test = struct {
+    name: []u8,
+    age: i32,
+};
+
+pub const TestClass = napi.Class(Test);

examples/basic/src/hello.zig

@@ -8,6 +8,7 @@ const array = @import("array.zig");
 const object = @import("object.zig");
 const function = @import("function.zig");
 const thread_safe_function = @import("thread_safe_function.zig");
+const class = @import("class.zig");
 const log = @import("log/log.zig");
 
 pub const test_i32 = number.test_i32;
@@ -38,6 +39,8 @@ pub const create_function = function.create_function;
 
 pub const call_thread_safe_function = thread_safe_function.call_thread_safe_function;
 
+pub const TestClass = class.TestClass;
+
 pub const test_hilog = log.test_hilog;
 
 comptime {

src/napi.zig

@@ -6,6 +6,7 @@ const module = @import("./prelude/module.zig");
 const worker = @import("./napi/wrapper/worker.zig");
 const err = @import("./napi/wrapper/error.zig");
 const thread_safe_function = @import("./napi/wrapper/thread_safe_function.zig");
+const class = @import("./napi/wrapper/class.zig");
 
 pub const napi_sys = @import("napi-sys");
 
@@ -30,6 +31,8 @@ pub const Function = function.Function;
 pub const CallbackInfo = callback_info.CallbackInfo;
 pub const Worker = worker.Worker;
 pub const ThreadSafeFunction = thread_safe_function.ThreadSafeFunction;
+pub const Class = class.Class;
+pub const ClassWithoutInit = class.ClassWithoutInit;
 
 pub const NODE_API_MODULE = module.NODE_API_MODULE;
 pub const NODE_API_MODULE_WITH_INIT = module.NODE_API_MODULE_WITH_INIT;

src/napi/util/allocator.zig

@@ -0,0 +1,31 @@
+const std = @import("std");
+
+pub const AllocatorManager = struct {
+    allocator: std.mem.Allocator,
+
+    const Self = @This();
+
+    pub fn init() Self {
+        return Self{
+            .allocator = std.heap.page_allocator,
+        };
+    }
+
+    pub fn get(self: *const Self) std.mem.Allocator {
+        return self.allocator;
+    }
+
+    pub fn set(self: *Self, new_allocator: std.mem.Allocator) void {
+        self.allocator = new_allocator;
+    }
+};
+
+pub const global_manager = AllocatorManager.init();
+
+pub fn globalAllocator() std.mem.Allocator {
+    return global_manager.get();
+}
+
+pub fn setGlobalAllocator(new_allocator: std.mem.Allocator) void {
+    global_manager.set(new_allocator);
+}

src/napi/util/helper.zig

@@ -192,3 +192,8 @@ pub fn collectFunctionArgs(comptime functions: anytype) type {
         .is_tuple = true,
     } });
 }
+
+pub fn shortTypeName(comptime T: type) []const u8 {
+    var iter = std.mem.splitBackwardsScalar(u8, @typeName(T), '.');
+    return iter.first();
+}

src/napi/util/napi.zig

@@ -6,6 +6,7 @@ const Env = @import("../env.zig").Env;
 const NapiError = @import("../wrapper/error.zig");
 const Function = @import("../value/function.zig").Function;
 const ThreadSafeFunction = @import("../wrapper/thread_safe_function.zig").ThreadSafeFunction;
+const class = @import("../wrapper/class.zig");
 
 pub const Napi = struct {
     pub fn from_napi_value(env: napi.napi_env, raw: napi.napi_value, comptime T: type) T {
@@ -202,6 +203,7 @@ pub const Napi = struct {
                             const array = try NapiValue.Array.New(Env.from_raw(env), value);
                             return array.raw;
                         }
+
                         const object = try NapiValue.Object.New(Env.from_raw(env), value);
                         return object.raw;
                     },
@@ -227,7 +229,9 @@ pub const Napi = struct {
                                 return NapiValue.String.New(Env.from_raw(env), value).raw;
                             },
                             else => {
-
+                                if (comptime class.isClass(value)) {
+                                    return try value.to_napi_value(Env.from_raw(env));
+                                }
                                 // TODO: Implement this
                                 @compileError("Unsupported type: " ++ @typeName(value));
                             },

src/napi/wrapper/callback_info.zig

@@ -7,6 +7,7 @@ pub const CallbackInfo = struct {
     raw: napi.napi_callback_info,
     env: napi.napi_env,
     args: []const value.NapiValue,
+    this: napi.napi_value,
 
     pub fn from_raw(env: napi.napi_env, raw: napi.napi_callback_info) CallbackInfo {
         var init_argc: usize = 0;
@@ -19,7 +20,9 @@ pub const CallbackInfo = struct {
         const args_raw = allocator.alloc(napi.napi_value, init_argc) catch @panic("OOM");
         defer allocator.free(args_raw);
 
-        const status2 = napi.napi_get_cb_info(env, raw, &init_argc, args_raw.ptr, null, null);
+        var this: napi.napi_value = undefined;
+
+        const status2 = napi.napi_get_cb_info(env, raw, &init_argc, args_raw.ptr, &this, null);
         if (status2 != napi.napi_ok) {
             @panic("Failed to get callback info");
         }
@@ -34,6 +37,7 @@ pub const CallbackInfo = struct {
             .raw = raw,
             .env = env,
             .args = result,
+            .this = this,
         };
     }
 
@@ -44,4 +48,8 @@ pub const CallbackInfo = struct {
     pub fn Get(self: CallbackInfo, index: usize) value.NapiValue {
         return self.args[index];
     }
+
+    pub fn This(self: CallbackInfo) napi.napi_value {
+        return self.this;
+    }
 };

src/napi/wrapper/class.zig

@@ -0,0 +1,225 @@
+const std = @import("std");
+const napi = @import("napi-sys").napi_sys;
+const CallbackInfo = @import("./callback_info.zig").CallbackInfo;
+const napi_env = @import("../env.zig");
+const Napi = @import("../util/napi.zig").Napi;
+const helper = @import("../util/helper.zig");
+const GlobalAllocator = @import("../util/allocator.zig");
+
+var class_constructors: std.StringHashMap(napi.napi_value) = std.StringHashMap(napi.napi_value).init(GlobalAllocator.globalAllocator());
+
+pub fn ClassWrapper(comptime T: type, comptime HasInit: bool) type {
+    const type_info = @typeInfo(T);
+    if (type_info != .@"struct") {
+        @compileError("Class() only support struct type");
+    }
+
+    if (type_info.@"struct".is_tuple) {
+        @compileError("Class() does not support tuple type");
+    }
+
+    const fields = type_info.@"struct".fields;
+    const decls = type_info.@"struct".decls;
+
+    const class_name = comptime helper.shortTypeName(T);
+    return struct {
+        const WrappedType = T;
+
+        env: napi.napi_env,
+        raw: napi.napi_value,
+
+        const Self = @This();
+
+        // 构造器回调
+        fn constructor_callback(env: napi.napi_env, callback_info: napi.napi_callback_info) callconv(.c) napi.napi_value {
+            const infos = CallbackInfo.from_raw(env, callback_info);
+
+            const data = GlobalAllocator.globalAllocator().create(T) catch return null;
+
+            if (@hasDecl(T, "init")) {
+                var tuple_args: std.meta.ArgsTuple(T.init) = undefined;
+                inline for (@typeInfo(std.meta.ArgsTuple(T.init)).@"fn".params, 0..) |arg, i| {
+                    tuple_args[i] = Napi.from_napi_value(infos.env, infos.args[i].raw, arg.type.?);
+                }
+
+                data.* = @call(.auto, T.init, tuple_args) catch {
+                    GlobalAllocator.globalAllocator().destroy(data);
+                    return null;
+                };
+            } else {
+                // init with zero
+                data.* = std.mem.zeroes(T);
+                // if HasInit, init with args with order of fields
+                if (comptime HasInit) {
+                    inline for (fields, 0..) |field, i| {
+                        @field(data.*, field.name) = Napi.from_napi_value(infos.env, infos.args[i].raw, field.type);
+                    }
+                }
+            }
+
+            const this_obj = infos.This();
+
+            var ref: napi.napi_ref = undefined;
+            const status = napi.napi_wrap(env, this_obj, data, finalize_callback, null, &ref);
+            if (status != napi.napi_ok) {
+                GlobalAllocator.globalAllocator().destroy(data);
+                return null;
+            }
+
+            var ref_count: u32 = undefined;
+            _ = napi.napi_reference_unref(env, ref, &ref_count);
+
+            return this_obj;
+        }
+
+        fn finalize_callback(env: napi.napi_env, data: ?*anyopaque, hint: ?*anyopaque) callconv(.c) void {
+            _ = env;
+            _ = hint;
+
+            if (data) |ptr| {
+                const typed_data: *T = @ptrCast(@alignCast(ptr));
+                if (@hasDecl(T, "deinit")) {
+                    typed_data.deinit();
+                }
+                GlobalAllocator.globalAllocator().destroy(typed_data);
+            }
+        }
+
+        fn define_class(env: napi.napi_env) !napi.napi_value {
+            comptime var property_count: usize = 0;
+            inline for (fields) |_| {
+                property_count += 1;
+            }
+            inline for (decls) |decl| {
+                if (@typeInfo(@TypeOf(@field(T, decl.name))) == .Fn and
+                    !std.mem.eql(u8, decl.name, "init") and
+                    !std.mem.eql(u8, decl.name, "deinit"))
+                {
+                    property_count += 1;
+                }
+            }
+
+            var properties: [property_count]napi.napi_property_descriptor = undefined;
+            var prop_idx: usize = 0;
+
+            inline for (fields) |field| {
+                const FieldAccessor = struct {
+                    fn getter(getter_env: napi.napi_env, info: napi.napi_callback_info) callconv(.c) napi.napi_value {
+                        const cb_info = CallbackInfo.from_raw(getter_env, info);
+                        var data: ?*anyopaque = null;
+                        _ = napi.napi_unwrap(getter_env, cb_info.This(), &data);
+                        if (data == null) return null;
+
+                        const instance: *T = @ptrCast(@alignCast(data.?));
+                        const field_value = @field(instance.*, field.name);
+                        return Napi.to_napi_value(getter_env, field_value, field.name) catch null;
+                    }
+
+                    fn setter(setter_env: napi.napi_env, info: napi.napi_callback_info) callconv(.c) napi.napi_value {
+                        const cb_info = CallbackInfo.from_raw(setter_env, info);
+                        var data: ?*anyopaque = null;
+                        _ = napi.napi_unwrap(setter_env, cb_info.This(), &data);
+                        if (data == null) return null;
+
+                        const instance: *T = @ptrCast(@alignCast(data.?));
+                        const args = cb_info.args;
+                        if (args.len > 0) {
+                            const new_value = Napi.from_napi_value(setter_env, args[0].raw, field.type);
+                            @field(instance.*, field.name) = new_value;
+                        }
+
+                        return null;
+                    }
+                };
+
+                properties[prop_idx] = napi.napi_property_descriptor{
+                    .utf8name = @ptrCast(field.name.ptr),
+                    .name = null,
+                    .method = null,
+                    .getter = FieldAccessor.getter,
+                    .setter = FieldAccessor.setter,
+                    .value = null,
+                    .attributes = napi.napi_default,
+                    .data = null,
+                };
+                prop_idx += 1;
+            }
+
+            inline for (decls) |decl| {
+                if (@typeInfo(@TypeOf(@field(T, decl.name))) == .Fn and
+                    !std.mem.eql(u8, decl.name, "init") and
+                    !std.mem.eql(u8, decl.name, "deinit"))
+                {
+                    const method = @field(T, decl.name);
+                    const method_info = @typeInfo(@TypeOf(method));
+                    const params = method_info.Fn.params;
+                    const is_instance_method = params.len > 0 and params[0].type.? == *T;
+
+                    const MethodWrapper = struct {
+                        fn call(method_env: napi.napi_env, info: napi.napi_callback_info) callconv(.c) napi.napi_value {
+                            const cb_info = CallbackInfo.from_raw(method_env, info);
+
+                            if (is_instance_method) {
+                                var data: ?*anyopaque = null;
+                                _ = napi.napi_unwrap(method_env, cb_info.This(), &data);
+                                if (data == null) return null;
+
+                                const instance: *T = @ptrCast(@alignCast(data.?));
+                                const result = method(instance);
+                                return Napi.to_napi_value(method_env, result, decl.name) catch null;
+                            } else {
+                                const result = method();
+                                return Napi.to_napi_value(method_env, result, decl.name) catch null;
+                            }
+                        }
+                    };
+
+                    properties[prop_idx] = napi.napi_property_descriptor{
+                        .utf8name = @ptrCast(decl.name.ptr),
+                        .name = null,
+                        .method = MethodWrapper.call,
+                        .getter = null,
+                        .setter = null,
+                        .value = null,
+                        .attributes = if (is_instance_method) napi.napi_default else napi.napi_static,
+                        .data = null,
+                    };
+                    prop_idx += 1;
+                }
+            }
+
+            var constructor: napi.napi_value = undefined;
+            _ = napi.napi_define_class(env, class_name.ptr, class_name.len, constructor_callback, null, prop_idx, &properties, &constructor);
+
+            try class_constructors.put(class_name, constructor);
+            return constructor;
+        }
+
+        fn define_custom_method(_: napi.napi_env, _: napi.napi_value) !void {}
+
+        /// to_napi_value will create a class constructor and return it
+        pub fn to_napi_value(env: napi_env.Env) !napi.napi_value {
+            const constructor = try Self.define_class(env.raw);
+
+            try Self.define_custom_method(env.raw, constructor);
+
+            return constructor;
+        }
+    };
+}
+
+/// Create a class with default constructor function
+pub fn Class(comptime T: type) type {
+    return ClassWrapper(T, true);
+}
+
+/// Create a class without default constructor function
+pub fn ClassWithoutInit(comptime T: type) type {
+    return ClassWrapper(T, false);
+}
+
+pub fn isClass(T: anytype) bool {
+    const type_name = @typeName(T);
+
+    return std.mem.indexOf(u8, type_name, "ClassWrapper") != null;
+}