scheduler done

zig-ecs/src/process/process.zig

@@ -1,3 +1,5 @@
+const std = @import("std");
+
 /// Processes are run by the Scheduler. They use a similar pattern to Allocators in that they are created and
 /// added as fields in a parent struct, your actual process that will be run.
 pub const Process = struct {
@@ -10,9 +12,11 @@ pub const Process = struct {
     abortedFn: ?fn (self: *Process) void = null,
     failedFn: ?fn (self: *Process) void = null,
     succeededFn: ?fn (self: *Process) void = null,
+    deinit: fn (self: *Process, allocator: *std.mem.Allocator) void = undefined,
 
     state: State = .uninitialized,
     stopped: bool = false,
+    next: ?*Process = null,
 
     pub fn getParent(self: *Process, comptime T: type) *T {
         return @fieldParentPtr(T, "process", self);

zig-ecs/src/process/scheduler.zig

@@ -11,96 +11,52 @@ const Process = @import("process.zig").Process;
 /// - when initializing the `process` field it ust be given an `updateFn`. All other callbacks are optional.
 /// - in any callback you can get your oiginal struct back via `process.getParent(@This())`
 pub const Scheduler = struct {
-    handlers: std.ArrayList(ProcessHandler),
+    processes: std.ArrayList(*Process),
     allocator: *std.mem.Allocator,
 
     /// helper to create and prepare a process and wrap it in a ProcessHandler
-    fn createProcessHandler(comptime T: type, data: var) ProcessHandler {
+    fn createProcessHandler(comptime T: type, data: var) *Process {
         var proc = std.testing.allocator.create(T) catch unreachable;
         proc.initialize(data);
 
         // get a closure so that we can safely deinit this later
-        var handlerDeinitFn = struct {
+        proc.process.deinit = struct {
             fn deinit(process: *Process, allocator: *std.mem.Allocator) void {
+                if (process.next) |next_process| {
+                    next_process.deinit(next_process, allocator);
+                }
                 allocator.destroy(@fieldParentPtr(T, "process", process));
             }
         }.deinit;
 
-        return .{
+        return &proc.process;
-            .process = &proc.process,
-            .deinitChild = handlerDeinitFn,
-        };
     }
 
+    /// returned when appending a process so that sub-processes can be added to the process
     const Continuation = struct {
-        handler: *ProcessHandler,
-
-        pub fn init(handler: *ProcessHandler) Continuation {
-            return .{ .handler = handler };
-        }
-
-        // TODO: fix and return this when ProcessHandler can have next be a ProcessHandler
-        pub fn next(self: *@This(), comptime T: type, data: var) void { // *@This()
-            var next_handler = createProcessHandler(T, data);
-            self.handler.next = .{ .deinitChild = next_handler.deinitChild, .process = next_handler.process };
-        }
-    };
-
-    /// TODO: remove this when ProcessHandler can have `next` be a ProcessHandler. For now this acts as a data store
-    /// holding the data ProcessHandler requires.
-    const NextProcessHandler = struct {
-        deinitChild: fn (process: *Process, allocator: *std.mem.Allocator) void,
         process: *Process,
 
-        pub fn asProcessHandler(self: @This()) ProcessHandler {
+        pub fn init(process: *Process) Continuation {
-            return .{ .deinitChild = self.deinitChild, .process = self.process };
+            return .{ .process = process };
         }
-    };
 
-    const ProcessHandler = struct {
+        pub fn next(self: *@This(), comptime T: type, data: var) *@This() {
-        deinitChild: fn (process: *Process, allocator: *std.mem.Allocator) void,
+            self.process.next = createProcessHandler(T, data);
-        process: *Process,
+            self.process = self.process.next.?;
-        next: ?NextProcessHandler = null,
+            return self;
-
-        pub fn update(self: *ProcessHandler, allocator: *std.mem.Allocator) bool {
-            self.process.tick();
-
-            if (self.process.dead()) {
-                if (!self.process.rejected() and self.next != null) {
-                    // kill the old Process parent
-                    self.deinitChild(self.process, allocator);
-
-                    // overwrite our fields and kick off the next process
-                    self.deinitChild = self.next.?.deinitChild;
-                    self.process = self.next.?.process;
-                    self.next = null; // TODO: when ProcessHandler can have next be a ProcessHandler
-                    return self.update(allocator);
-                } else {
-                    return true;
-                }
-            }
-
-            return false;
-        }
-
-        pub fn deinit(self: @This(), allocator: *std.mem.Allocator) void {
-            if (self.next) |next_handler| {
-                next_handler.asProcessHandler().deinit(allocator);
-            }
-            self.deinitChild(self.process, allocator);
         }
     };
 
     pub fn init(allocator: *std.mem.Allocator) Scheduler {
         return .{
-            .handlers = std.ArrayList(ProcessHandler).init(allocator),
+            .processes = std.ArrayList(*Process).init(allocator),
             .allocator = allocator,
         };
     }
 
     pub fn deinit(self: *Scheduler) void {
         self.clear();
-        self.handlers.deinit();
+        self.processes.deinit();
     }
 
     /// Schedules a process for the next tick
@@ -108,22 +64,44 @@ pub const Scheduler = struct {
         std.debug.assert(@hasDecl(T, "initialize"));
         std.debug.assert(@hasField(T, "process"));
 
-        var handler = createProcessHandler(T, data);
+        var process = createProcessHandler(T, data);
-        handler.process.tick();
+        process.tick();
+
+        self.processes.append(process) catch unreachable;
+        return Continuation.init(process);
+    }
+
+    fn updateProcess(process: **Process, allocator: *std.mem.Allocator) bool {
+        const current_process = process.*;
+        current_process.tick();
+
+        if (current_process.dead()) {
+            if (!current_process.rejected() and current_process.next != null) {
+                // grab the next process and null it out so we dont double-free it later
+                const next_process = current_process.next.?;
+                current_process.next = null;
+                process.* = next_process;
+
+                // kill the old Process parent
+                current_process.deinit(current_process, allocator);
+                return updateProcess(process, allocator);
+            } else {
+                return true;
+            }
+        }
 
-        self.handlers.append(handler) catch unreachable;
+        return false;
-        return Continuation.init(&self.handlers.items[self.handlers.items.len - 1]);
     }
 
     /// Updates all scheduled processes
     pub fn update(self: *Scheduler) void {
-        if (self.handlers.items.len == 0) return;
+        if (self.processes.items.len == 0) return;
 
-        var i: usize = self.handlers.items.len - 1;
+        var i: usize = self.processes.items.len - 1;
         while (true) : (i -= 1) {
-            if (self.handlers.items[i].update(self.allocator)) {
+            if (updateProcess(&self.processes.items[i], self.allocator)) {
-                var dead_handler = self.handlers.swapRemove(i);
+                var dead_process = self.processes.swapRemove(i);
-                dead_handler.deinit(self.allocator);
+                dead_process.deinit(dead_process, self.allocator);
             }
 
             if (i == 0) break;
@@ -132,20 +110,20 @@ pub const Scheduler = struct {
 
     /// gets the number of processes still running
     pub fn len(self: Scheduler) usize {
-        return self.handlers.items.len;
+        return self.processes.items.len;
     }
 
     /// resets the scheduler to its initial state and discards all the processes
     pub fn clear(self: *Scheduler) void {
-        for (self.handlers.items) |handler| {
+        for (self.processes.items) |process| {
-            handler.deinit(self.allocator);
+            process.deinit(process, self.allocator);
         }
-        self.handlers.items.len = 0;
+        self.processes.items.len = 0;
     }
 
     /// Aborts all scheduled processes. Unless an immediate operation is requested, the abort is scheduled for the next tick
     pub fn abort(self: *Scheduler, immediately: bool) void {
-        for (self.handlers.items) |handler| {
+        for (self.processes.items) |handler| {
             handler.process.abort(immediately);
         }
     }
@@ -170,27 +148,27 @@ test "" {
         }
 
         fn start(process: *Process) void {
-            const self = @fieldParentPtr(@This(), "process", process);
+            const self = process.getParent(@This());
             // std.debug.warn("start {}\n", .{self.fart});
         }
 
         fn aborted(process: *Process) void {
-            const self = @fieldParentPtr(@This(), "process", process);
+            const self = process.getParent(@This());
             // std.debug.warn("aborted {}\n", .{self.fart});
         }
 
         fn failed(process: *Process) void {
-            const self = @fieldParentPtr(@This(), "process", process);
+            const self = process.getParent(@This());
             // std.debug.warn("failed {}\n", .{self.fart});
         }
 
         fn succeeded(process: *Process) void {
-            const self = @fieldParentPtr(@This(), "process", process);
+            const self = process.getParent(@This());
             // std.debug.warn("succeeded {}\n", .{self.fart});
         }
 
         fn update(process: *Process) void {
-            const self = @fieldParentPtr(@This(), "process", process);
+            const self = process.getParent(@This());
             // std.debug.warn("update {}\n", .{self.fart});
             process.succeed();
         }
@@ -199,7 +177,9 @@ test "" {
     var scheduler = Scheduler.init(std.testing.allocator);
     defer scheduler.deinit();
 
-    _ = scheduler.attach(Tester, 33).next(Tester, 66);
+    _ = scheduler.attach(Tester, 33).next(Tester, 66).next(Tester, 88).next(Tester, 99);
+    scheduler.update();
+    scheduler.update();
     scheduler.update();
     scheduler.update();
     scheduler.update();

zig-ecs/src/tests.zig

@@ -17,4 +17,7 @@ comptime {
     // resources
     _ = @import("resources/cache.zig");
     _ = @import("resources/assets.zig");
+
+    // process
+    _ = @import("process/scheduler.zig");
 }