From 01da174126b26075c24fb03562f14e619e3e03c5 Mon Sep 17 00:00:00 2001
From: cosmonaut <evan@moonside.games>
Date: Sat, 5 Dec 2020 14:19:17 -0800
Subject: [PATCH] fix store allocs and deallocs

---
 src/component_manager.zig |  9 ++++++++-
 src/component_store.zig   | 20 +++++++++++++++++---
 src/type_store.zig        | 34 +++++++---------------------------
 3 files changed, 32 insertions(+), 31 deletions(-)

diff --git a/src/component_manager.zig b/src/component_manager.zig
index 9bde171..b1e3881 100644
--- a/src/component_manager.zig
+++ b/src/component_manager.zig
@@ -21,11 +21,18 @@ pub const ComponentManager = struct {
     }
 
     pub fn deinit(self: *Self) void {
+        var iter = self.component_stores.map.iterator();
+        while (iter.next()) |ptr| {
+            var storage = @intToPtr(*ComponentStore(u1), ptr.value);
+            storage.deinit();
+            self.allocator.destroy(storage);
+        }
         self.component_stores.deinit();
     }
 
     pub fn register(self: *Self, comptime TComponent: type) void {
-        self.component_stores.add(ComponentStore(TComponent).init(self.allocator));
+        const ptr = ComponentStore(TComponent).heapInit(self.allocator);
+        self.component_stores.add(ptr.*);
     }
 
     pub fn add_component(self: *Self, entityID: usize, component: anytype) void {
diff --git a/src/component_store.zig b/src/component_store.zig
index 50b026f..72172b3 100644
--- a/src/component_store.zig
+++ b/src/component_store.zig
@@ -14,6 +14,7 @@ pub fn ComponentStore(comptime TComponent: type) type {
         entityIDToIndex: std.AutoArrayHashMap(usize, usize),
         indexToEntity: std.ArrayList(Entity),
         components: std.ArrayList(TComponent),
+        safeDeinit: fn (*Self) void,
 
         pub fn init(allocator: *Allocator) Self {
             return Self {
@@ -21,13 +22,26 @@ pub fn ComponentStore(comptime TComponent: type) type {
                 .entityIDToIndex = std.AutoArrayHashMap(usize, usize).init(allocator),
                 .indexToEntity = std.ArrayList(Entity).init(allocator),
                 .components = std.ArrayList(TComponent).init(allocator),
+                .safeDeinit = struct {
+                    // we need to enclose the type here
+                    // which is why this indirection exists for deinit
+                    fn deinit(self: *Self) void {
+                        self.entityIDToIndex.deinit();
+                        self.indexToEntity.deinit();
+                        self.components.deinit();
+                    }
+                }.deinit,
             };
         }
 
+        pub fn heapInit(allocator: *Allocator) *Self {
+            var ptr = allocator.create(Self) catch unreachable;
+            ptr.* = init(allocator);
+            return ptr;
+        }
+
         pub fn deinit(self: *Self) void {
-            self.entityIDToIndex.deinit();
-            self.indexToEntity.deinit();
-            self.components.deinit();
+            self.safeDeinit(self);
         }
 
         pub fn has(self: Self, entityID: usize) bool {
diff --git a/src/type_store.zig b/src/type_store.zig
index 0688a8b..46aea5f 100644
--- a/src/type_store.zig
+++ b/src/type_store.zig
@@ -4,34 +4,30 @@ const std = @import("std");
 
 /// stores a single object of type T for each T added
 pub const TypeStore = struct {
-    map: std.AutoHashMap(u32, []u8),
+    map: std.AutoHashMap(u32, usize),
     allocator: *std.mem.Allocator,
 
     pub fn init(allocator: *std.mem.Allocator) TypeStore {
         return TypeStore{
-            .map = std.AutoHashMap(u32, []u8).init(allocator),
+            .map = std.AutoHashMap(u32, usize).init(allocator),
             .allocator = allocator,
         };
     }
 
     pub fn deinit(self: *TypeStore) void {
         var iter = self.map.iterator();
-        while (iter.next()) |kv| {
-            self.allocator.free(kv.value);
-        }
         self.map.deinit();
     }
 
     /// adds instance, returning a pointer to the item as it lives in the store
     pub fn add(self: *TypeStore, instance: anytype) void {
-        var bytes = self.allocator.alloc(u8, @sizeOf(@TypeOf(instance))) catch unreachable;
-        std.mem.copy(u8, bytes, std.mem.asBytes(&instance));
-        _ = self.map.put(typeId(@TypeOf(instance)), bytes) catch unreachable;
+        var ptr = @ptrToInt(&instance);
+        _ = self.map.put(typeId(@TypeOf(instance)), ptr) catch unreachable;
     }
 
     pub fn get(self: *TypeStore, comptime T: type) *T {
-        if (self.map.get(typeId(T))) |bytes| {
-            return @ptrCast(*T, @alignCast(@alignOf(T), bytes));
+        if (self.map.get(typeId(T))) |ptr| {
+            return @intToPtr(*T, ptr);
         }
         unreachable;
     }
@@ -40,17 +36,8 @@ pub const TypeStore = struct {
         return self.get(T).*;
     }
 
-    pub fn getOrAdd(self: *TypeStore, comptime T: type) *T {
-        if (!self.has(T)) {
-            var instance = std.mem.zeroes(T);
-            self.add(instance);
-        }
-        return self.get(T);
-    }
-
     pub fn remove(self: *TypeStore, comptime T: type) void {
-        if (self.map.get(typeId(T))) |bytes| {
-            self.allocator.free(bytes);
+        if (self.map.get(typeId(T))) |ptr| {
             _ = self.map.remove(typeId(T));
         }
     }
@@ -95,11 +82,4 @@ test "TypeStore" {
 
     store.remove(Vector);
     std.testing.expect(!store.has(Vector));
-
-    var v3 = store.getOrAdd(u32);
-    std.testing.expectEqual(v3.*, 0);
-    v3.* = 777;
-
-    var v4 = store.get(u32);
-    std.testing.expectEqual(v3.*, 777);
 }