Basic controller impl., some file reordering

src/graph.zig

@@ -1,60 +1,27 @@
 const std = @import("std");
+const utils = @import("graph/utils.zig");
+const Resource = @import("graph/resource.zig");
+const System = @import("graph/system.zig");
 
 // TODO:
 // - Use arena allocator?
 // - Resolve missing resource problem
-// - Split up this file
+
+pub const Controller = Resource.Controller;
 
 const MAX_SYSTEM_REQUESTS = 8;
 const DEFAULT_SYSTEM_CAPACITY = 16;
+const DEFAULT_CONTROLLERS = 2;
 
-const HashType = u32;
+const ResourceMap = std.AutoArrayHashMapUnmanaged(utils.Hash, Resource);
-pub const HashAlgorithm = std.crypto.hash.blake2.Blake2s(32);
-
-const Resource = struct {
-    /// Aligned pointer
-    pointer: *anyopaque,
-    /// Storage
-    mem: []u8,
-};
-const ResourceMap = std.AutoArrayHashMapUnmanaged(u32, Resource);
-
-const System = struct {
-    const Request = union(enum) {
-        resource: HashType,
-        // TODO:
-        // - Params
-        // - Controller
-    };
-    const RequestList = []const Request;
-
-    function_runner: *const fn ([]const *anyopaque) void,
-    requested_types: RequestList,
-
-    fn from_function(comptime function: anytype, alloc: std.mem.Allocator) !System {
-        validate_system(function);
-
-        var requests: [@typeInfo(@TypeOf(function)).Fn.params.len]Request = undefined;
-        inline for (0.., @typeInfo(@TypeOf(function)).Fn.params) |i, param| {
-            switch (@typeInfo(param.type.?).Pointer.child) {
-                else => |resource_type| requests[i] = .{ .resource = hash_type(resource_type) },
-            }
-        }
-
-        return System{
-            .requested_types = try alloc.dupe(Request, &requests),
-            .function_runner = generate_runner(function),
-        };
-    }
-    fn deinit(self: System, alloc: std.mem.Allocator) void {
-        alloc.free(self.requested_types);
-    }
-};
 const SystemQueue = std.ArrayListUnmanaged(System);
+const Controllers = std.ArrayListUnmanaged(Controller);
 
+/// Assumed to be thread-safe
 alloc: std.mem.Allocator,
 resources: ResourceMap,
 system_queue: SystemQueue,
+controllers: Controllers,
 
 const Self = @This();
 pub fn init(alloc: std.mem.Allocator) !Self {
@@ -64,17 +31,30 @@ pub fn init(alloc: std.mem.Allocator) !Self {
     var system_queue = try SystemQueue.initCapacity(alloc, DEFAULT_SYSTEM_CAPACITY);
     errdefer system_queue.deinit(alloc);
 
+    var controllers = try Controllers.initCapacity(alloc, DEFAULT_CONTROLLERS);
+    errdefer controllers.deinit(alloc);
+
+    errdefer for (controllers.items) |*controller| {
+        controller.deinit();
+    };
+
+    for (0..DEFAULT_CONTROLLERS) |_| {
+        const controller = try Controller.create(alloc);
+        controllers.appendAssumeCapacity(controller);
+    }
+
     return .{
         .alloc = alloc,
         .resources = resources,
         .system_queue = system_queue,
+        .controllers = controllers,
     };
 }
 
 pub fn deinit(self: *Self) void {
     var resource_iter = self.resources.iterator();
     while (resource_iter.next()) |entry| {
-        self.alloc.free(entry.value_ptr.mem);
+        entry.value_ptr.deinit(self.alloc);
     }
     self.resources.clearAndFree(self.alloc);
     self.resources.deinit(self.alloc);
@@ -83,159 +63,105 @@ pub fn deinit(self: *Self) void {
         self.alloc.free(system.requested_types);
     }
     self.system_queue.deinit(self.alloc);
+
+    for (self.controllers.items) |*controller| {
+        controller.deinit();
+    }
+    self.controllers.deinit(self.alloc);
 }
 
-fn enqueue_system(self: *Self, comptime function: anytype) !void {
+fn enqueue_system(self: *Self, system: System) !void {
-    validate_system(function);
-    const system = try System.from_function(function, self.alloc);
     errdefer system.deinit(self.alloc);
-
     try self.system_queue.append(self.alloc, system);
 }
 
 fn run_all_systems(self: *Self) GraphError!void {
     while (self.system_queue.items.len > 0) {
-        const next_system = self.system_queue.getLast();
+        const next_system = self.system_queue.pop();
         defer next_system.deinit(self.alloc);
-        defer _ = self.system_queue.pop();
 
         try self.run_system(next_system);
     }
 }
 
-/// Does not consume the system
+/// Does not deallocate the system
 fn run_system(self: *Self, system: System) GraphError!void {
     var buffer: [MAX_SYSTEM_REQUESTS]*anyopaque = undefined;
+    var controller: ?Controller = null;
+    errdefer if (controller) |*c| c.deinit();
+
     var buffer_len: usize = 0;
     for (system.requested_types) |request| {
         switch (request) {
             .resource => |resource| {
                 buffer[buffer_len] = self.get_anyopaque_resource(resource) orelse return GraphError.MissingResource;
             },
+            .controller => {
+                controller = try self.get_controller();
+                buffer[buffer_len] = @ptrCast(&controller.?);
+            },
         }
         buffer_len += 1;
     }
     system.function_runner(buffer[0..buffer_len]);
+
+    if (controller) |c| {
+        defer controller = null;
+        try self.free_controller(c);
+    }
+}
+
+fn apply_commands(self: *Self, commands: []const Controller.Command) !void {
+    for (commands) |command| {
+        switch (command) {
+            .add_resource => |r| try self.add_resource(r),
+            .queue_system => |s| try self.enqueue_system(s),
+        }
+    }
+}
+
+fn get_controller(self: *Self) !Controller {
+    if (self.controllers.popOrNull()) |c| {
+        return c;
+    }
+    return Controller.create(self.alloc);
+}
+
+/// Evaluates and clears the controller (even if errors out)
+fn free_controller(self: *Self, controller: Controller) !void {
+    var c = controller;
+    try self.apply_commands(c.commands());
+    c.clear();
+    try self.controllers.append(self.alloc, c);
+    // TODO: Handle controller error state
 }
 
 pub inline fn get_resource(self: *Self, comptime resource: type) ?*resource {
-    validate_resource(resource);
+    utils.validate_resource(resource);
-    if (get_anyopaque_resource(self, hash_type(resource))) |ptr| {
+    if (get_anyopaque_resource(self, utils.hash_type(resource))) |ptr| {
         return @alignCast(@ptrCast(ptr));
     }
     return null;
 }
 
-fn get_anyopaque_resource(self: *Self, resource_hash: HashType) ?*anyopaque {
+fn get_anyopaque_resource(self: *Self, resource_hash: utils.Hash) ?*anyopaque {
     if (self.resources.get(resource_hash)) |resource| {
         return resource.pointer;
     }
     return null;
 }
 
-/// Copies resource into storage, returning previous value if any
+/// Discards any previous resource data, resource is assumed to be allocated with `self.alloc`
-pub inline fn add_resource(self: *Self, resource: anytype) !?@TypeOf(resource) {
+pub inline fn add_resource(self: *Self, resource: Resource) !void {
-    validate_resource(@TypeOf(resource));
+    var previous = try self.resources.fetchPut(self.alloc, resource.hash, resource);
-    var previous: @TypeOf(resource) = undefined;
+    if (previous) |*p| {
-    if (try self.add_anyopaque_resource(
+        p.value.deinit(self.alloc);
-        @ptrCast(&resource),
-        hash_type(@TypeOf(resource)),
-        @sizeOf(@TypeOf(resource)),
-        @alignOf(@TypeOf(resource)),
-        @ptrCast(&previous),
-    )) {
-        return previous;
     }
-    return null;
-}
-
-/// `previous_output` is expected to be aligned accordingly
-fn add_anyopaque_resource(
-    self: *Self,
-    resource: *const anyopaque,
-    hash: HashType,
-    size: usize,
-    align_to: usize,
-    previous_output: *anyopaque,
-) !bool {
-    // TODO: Review this shady function
-    const resource_buffer = try self.alloc.alloc(u8, size + align_to);
-    errdefer self.alloc.free(resource_buffer);
-
-    const align_offset = std.mem.alignPointerOffset(
-        @as([*]u8, @ptrCast(resource_buffer)),
-        align_to,
-    ) orelse unreachable;
-
-    @memcpy(
-        resource_buffer[align_offset..size],
-        @as([*]const u8, @ptrCast(resource))[0..size],
-    );
-    const previous = try self.resources.fetchPut(self.alloc, hash, .{
-        .pointer = @ptrCast(resource_buffer[align_offset..]),
-        .mem = resource_buffer,
-    });
-    if (previous) |previous_value| {
-        @memcpy(
-            @as([*]u8, @ptrCast(previous_output)),
-            @as([*]const u8, @ptrCast(&previous_value.value.pointer))[0..size],
-        );
-        self.alloc.free(previous_value.value.mem);
-        return true;
-    }
-    return false;
-}
-
-inline fn hash_type(comptime h_type: type) HashType {
-    return hash_string(@typeName(h_type));
-}
-
-fn hash_string(comptime name: []const u8) HashType {
-    @setEvalBranchQuota(100000);
-    var output: [@divExact(@bitSizeOf(HashType), 8)]u8 = undefined;
-
-    HashAlgorithm.hash(name, &output, .{});
-    return std.mem.readInt(
-        HashType,
-        output[0..],
-        @import("builtin").cpu.arch.endian(),
-    );
-}
-
-fn validate_resource(comptime resource_type: type) void {
-    switch (@typeInfo(resource_type)) {
-        .Struct, .Enum, .Union => return,
-        else => @compileError("Invalid resource type \"" ++ @typeName(resource_type) ++ "\""),
-    }
-}
-
-fn validate_system(comptime system: anytype) void {
-    const info = @typeInfo(@TypeOf(system));
-    if (info != .Fn) @compileError("System can only be a function, got " ++ @typeName(system));
-    if (info.Fn.return_type != void) @compileError("Systems are not allowed to return any value (" ++ @typeName(info.Fn.return_type.?) ++ " returned)");
-    if (info.Fn.is_var_args) @compileError("System cannot be variadic");
-    if (info.Fn.is_generic) @compileError("System cannot be generic");
-    inline for (info.Fn.params) |param| {
-        if (@typeInfo(param.type.?) != .Pointer) @compileError("Systems can only have pointer parameters");
-        validate_resource(@typeInfo(param.type.?).Pointer.child);
-    }
-}
-
-fn generate_runner(comptime system: anytype) fn ([]const *anyopaque) void {
-    const RunnerImpl = struct {
-        fn runner(resources: []const *anyopaque) void {
-            var args: std.meta.ArgsTuple(@TypeOf(system)) = undefined;
-            inline for (0..@typeInfo(@TypeOf(system)).Fn.params.len) |index| {
-                args[index] = @alignCast(@ptrCast(resources[index]));
-            }
-            @call(.always_inline, system, args);
-        }
-    };
-    return RunnerImpl.runner;
 }
 
 const GraphError = error{
     MissingResource,
+    OutOfMemory,
 };
 
 test {
@@ -249,19 +175,26 @@ test {
         fn add_ten(rsc: *@This()) void {
             rsc.number += 10;
         }
+        fn add_eleven(cmd: *Controller) void {
+            cmd.queue_system(add_ten);
+            cmd.queue_system(add_one);
+        }
     };
 
     var graph = try Graph.init(std.testing.allocator);
     defer graph.deinit();
 
-    try std.testing.expectEqual(graph.add_resource(TestResource{ .number = 100 }), null);
+    var controller = try graph.get_controller();
+    controller.add_resource(TestResource{ .number = 100 });
 
-    try graph.enqueue_system(TestResource.add_one);
+    controller.queue_system(TestResource.add_one);
-    try graph.enqueue_system(TestResource.add_one);
+    controller.queue_system(TestResource.add_one);
-    try graph.enqueue_system(TestResource.add_one);
 
-    try graph.enqueue_system(TestResource.add_ten);
+    controller.queue_system(TestResource.add_ten);
-    try graph.enqueue_system(TestResource.add_ten);
+
+    controller.queue_system(TestResource.add_eleven);
+
+    try graph.free_controller(controller);
 
     try graph.run_all_systems();
 

src/graph/resource.zig

@@ -0,0 +1,132 @@
+const std = @import("std");
+const utils = @import("utils.zig");
+const System = @import("system.zig");
+const Resource = @This();
+
+const DEFAULT_CONTROLLER_CAPACITY = 8;
+
+/// Resource data
+pointer: *anyopaque,
+/// Pointer to the memory allocted for this resource
+buffer: []u8,
+alignment: u29,
+hash: utils.Hash,
+
+pub fn deinit(self: *Resource, alloc: std.mem.Allocator) void {
+    alloc.free(self.buffer);
+}
+
+pub const Controller = struct {
+    alloc: std.mem.Allocator,
+    command_buffer: std.ArrayListUnmanaged(Command),
+    error_state: ErrorState,
+
+    pub const Command = union(enum) {
+        add_resource: Resource,
+        queue_system: System,
+    };
+    pub const ErrorState = union(enum) {
+        ok: void,
+        recoverable: []const u8,
+        unrecoverable: void,
+    };
+
+    pub fn create(alloc: std.mem.Allocator) !Controller {
+        return .{
+            .alloc = alloc,
+            .command_buffer = try std.ArrayListUnmanaged(Command).initCapacity(alloc, DEFAULT_CONTROLLER_CAPACITY),
+            .error_state = .ok,
+        };
+    }
+
+    /// Returns command queue, caller is responsible for freeing it's data
+    /// Call `clean()` afterwards, to clear the command queue
+    pub fn commands(self: *Controller) []const Command {
+        return self.command_buffer.items;
+    }
+
+    /// Clears the command buffer, but does not deallocate it's contents
+    pub fn clear(self: *Controller) void {
+        self.command_buffer.clearRetainingCapacity();
+        switch (self.error_state) {
+            .ok, .unrecoverable => {},
+            .recoverable => |msg| self.alloc.free(msg),
+        }
+        self.error_state = .ok;
+    }
+
+    /// Adds resource to the global storage, discarding any previously existing data
+    pub inline fn add_resource(self: *Controller, resource: anytype) void {
+        utils.validate_resource(@TypeOf(resource));
+
+        self.add_anyopaque_resource(
+            @ptrCast(&resource),
+            utils.hash_type(@TypeOf(resource)),
+            @sizeOf(@TypeOf(resource)),
+            @alignOf(@TypeOf(resource)),
+        ) catch |err| self.fail(err);
+    }
+
+    pub fn queue_system(self: *Controller, comptime function: anytype) void {
+        utils.validate_system(function);
+
+        self.queue_system_internal(function) catch |err| self.fail(err);
+    }
+
+    fn queue_system_internal(self: *Controller, comptime function: anytype) !void {
+        var system = try System.from_function(function, self.alloc);
+        errdefer system.deinit(self.alloc);
+
+        try self.command_buffer.append(self.alloc, .{ .queue_system = system });
+    }
+
+    /// `previous_output` is expected to be aligned accordingly
+    fn add_anyopaque_resource(
+        self: *Controller,
+        resource: *const anyopaque,
+        hash: utils.Hash,
+        size: usize,
+        align_to: u29,
+    ) !void {
+        // TODO: Review this shady function
+        const resource_buffer = try self.alloc.alloc(u8, size + align_to - 1);
+        errdefer self.alloc.free(resource_buffer);
+
+        const align_offset = std.mem.alignPointerOffset(
+            @as([*]u8, @ptrCast(resource_buffer)),
+            align_to,
+        ) orelse unreachable;
+
+        @memcpy(
+            resource_buffer[align_offset..size],
+            @as([*]const u8, @ptrCast(resource))[0..size],
+        );
+
+        try self.command_buffer.append(self.alloc, .{ .add_resource = .{
+            .pointer = @ptrCast(resource_buffer[align_offset..]),
+            .buffer = resource_buffer,
+            .alignment = align_to,
+            .hash = hash,
+        } });
+    }
+
+    const ControllerError = std.mem.Allocator.Error;
+    fn fail(self: *Controller, err: ControllerError) void {
+        if (self.error_state == .unrecoverable) return;
+        if (self.error_state == .recoverable) self.alloc.free(self.error_state.recoverable);
+        switch (err) {
+            error.OutOfMemory => self.error_state = .unrecoverable,
+        }
+    }
+
+    pub fn deinit(self: *Controller) void {
+        for (self.command_buffer.items) |*command| {
+            switch (command.*) {
+                .add_resource => |*resource| resource.deinit(self.alloc),
+                .queue_system => |*system| system.deinit(self.alloc),
+            }
+        }
+        self.clear();
+        self.command_buffer.deinit(self.alloc);
+    }
+};

src/graph/system.zig

@@ -0,0 +1,35 @@
+const std = @import("std");
+const utils = @import("utils.zig");
+const Controller = @import("resource.zig").Controller;
+
+function_runner: *const fn ([]const *anyopaque) void,
+requested_types: []const Request,
+
+pub const Request = union(enum) {
+    resource: utils.Hash,
+    controller: void,
+    // TODO:
+    // - Params
+};
+
+const Self = @This();
+pub fn from_function(comptime function: anytype, alloc: std.mem.Allocator) !Self {
+    utils.validate_system(function);
+
+    var requests: [@typeInfo(@TypeOf(function)).Fn.params.len]Request = undefined;
+    inline for (0.., @typeInfo(@TypeOf(function)).Fn.params) |i, param| {
+        switch (@typeInfo(param.type.?).Pointer.child) {
+            Controller => requests[i] = .controller,
+            else => |resource_type| requests[i] = .{ .resource = utils.hash_type(resource_type) },
+        }
+    }
+
+    return Self{
+        .requested_types = try alloc.dupe(Request, &requests),
+        .function_runner = utils.generate_runner(function),
+    };
+}
+
+pub fn deinit(self: *const Self, alloc: std.mem.Allocator) void {
+    alloc.free(self.requested_types);
+}

src/graph/utils.zig

@@ -0,0 +1,63 @@
+const std = @import("std");
+const Resource = @import("resource.zig");
+const System = @import("system.zig");
+
+pub const Hash = u32;
+const HashAlgorithm = std.crypto.hash.blake2.Blake2s(@bitSizeOf(Hash));
+
+pub inline fn hash_type(comptime h_type: type) Hash {
+    return hash_string(@typeName(h_type));
+}
+
+pub fn hash_string(comptime name: []const u8) Hash {
+    @setEvalBranchQuota(100000);
+    var output: [@divExact(@bitSizeOf(Hash), 8)]u8 = undefined;
+
+    HashAlgorithm.hash(name, &output, .{});
+    return std.mem.readInt(
+        Hash,
+        output[0..],
+        @import("builtin").cpu.arch.endian(),
+    );
+}
+
+pub fn validate_resource(comptime resource_type: type) void {
+    switch (@typeInfo(resource_type)) {
+        .Struct, .Enum, .Union => return,
+        else => @compileError("Invalid resource type \"" ++ @typeName(resource_type) ++ "\""),
+    }
+}
+
+pub fn validate_system(comptime system: anytype) void {
+    const info = @typeInfo(@TypeOf(system));
+    if (info != .Fn) @compileError("System can only be a function, got " ++ @typeName(system));
+    if (info.Fn.return_type != void) @compileError("Systems are not allowed to return any value (" ++ @typeName(info.Fn.return_type.?) ++ " returned)");
+    if (info.Fn.is_var_args) @compileError("System cannot be variadic");
+    if (info.Fn.is_generic) @compileError("System cannot be generic");
+
+    const controller_requests: usize = 0;
+    inline for (info.Fn.params) |param| {
+        if (@typeInfo(param.type.?) != .Pointer) @compileError("Systems can only have pointer parameters");
+        switch (@typeInfo(param.type.?).Pointer.child) {
+            Resource.Controller => {
+                // controller_requests += 1;
+                // _ = &controller_requests;
+            },
+            else => |t| validate_resource(t),
+        }
+    }
+    if (controller_requests > 1) @compileError("A system cannot request controller more than once");
+}
+
+pub fn generate_runner(comptime system: anytype) fn ([]const *anyopaque) void {
+    const RunnerImpl = struct {
+        fn runner(resources: []const *anyopaque) void {
+            var args: std.meta.ArgsTuple(@TypeOf(system)) = undefined;
+            inline for (0..@typeInfo(@TypeOf(system)).Fn.params.len) |index| {
+                args[index] = @alignCast(@ptrCast(resources[index]));
+            }
+            @call(.always_inline, system, args);
+        }
+    };
+    return RunnerImpl.runner;
+}