refactor(core/policy): 将接口返回类型从 bool 调整为 void

policy_route_event/policy_apply_command 两个函数的 out 参数中已经能包
含返回值所代表的意义了，因此直接将这两个函数的返回类型改为 void

src/core/policy.c

@@ -18,13 +18,13 @@ static workspace_id_t derive_window_workspace(const state_t *state) {
   return state->outputs[state->current_output_index].current_workspace_id;
 }
 
-static bool route_map_request(
+static void route_map_request(
   const state_t *state,
   const rules_t *rules,
   const window_map_request_event_t *e,
   command_buffer_t *out
 ) {
-  if (state_window_get(state, e->window)) return false;
+  if (state_window_get(state, e->window)) return;
 
   window_layer_type_t layer_type = window_classify_layer(&e->props);
   if (e->transient_for != ZDWM_WINDOW_ID_INVALID) {
@@ -91,11 +91,9 @@ static bool route_map_request(
       command_buffer_push(out, &switch_workspace_cmd);
     }
   }
-
-  return true;
 }
 
-bool policy_route_event(
+void policy_route_event(
   const policy_context_t *ctx,
   const event_t *event,
   command_buffer_t *out
@@ -104,14 +102,14 @@ bool policy_route_event(
   switch (event->type) {
   case ZDWM_EVENT_WINDOW_MAP_REQUEST: {
     auto rules = ctx->rules;
-    return route_map_request(state, rules, &event->as.window_map_request, out);
+    route_map_request(state, rules, &event->as.window_map_request, out);
+    break;
   }
   default:
-    return false;
   }
 }
 
-static bool manage_window(
+static void manage_window(
   const policy_context_t *ctx,
   const manage_window_command_t *command,
   plan_t *plan
@@ -122,7 +120,7 @@ static bool manage_window(
   state_window_set_workspace(state, window_id, command->workspace);
   state_window_set_floating(state, window_id, command->floating);
 
-  if (!state_workspace_show(state, command->workspace)) return false;
+  if (!state_workspace_show(state, command->workspace)) return;
 
   effect_t map_effect = {
     .type          = ZDWM_EFFECT_MAP_WINDOW,
@@ -133,11 +131,9 @@ static bool manage_window(
   if (window_need_layout(window)) {
     plan->need_relayout = true;
   }
-
-  return true;
 }
 
-static bool switch_workspace(
+static void switch_workspace(
   state_t *state,
   const switch_workspace_command_t *command,
   plan_t *plan
@@ -154,32 +150,24 @@ static bool switch_workspace(
   }
 
   /* TODO: 后续考虑加上 ewmh 相关副作用 */
-
-  return false;
 }
 
-bool policy_apply_command(
+void policy_apply_command(
   const policy_context_t *ctx,
   const command_buffer_t *command_buffer,
   plan_t *plan
 ) {
-  bool has_effect = false;
   auto state = ctx->state;
   for (size_t i = 0; i < command_buffer->count; ++i) {
     auto cmd = &command_buffer->items[i];
     switch (cmd->type) {
     case ZDWM_COMMAND_MANAGE_WINDOW:
-      if (manage_window(ctx, &cmd->as.manage_window, plan)) {
-        has_effect = true;
-      }
+      manage_window(ctx, &cmd->as.manage_window, plan);
       break;
     case ZDWM_COMMAND_SWITCH_WORKSPACE:
-      if (switch_workspace(state, &cmd->as.switch_workspace, plan)) {
-        has_effect = true;
-      }
+      switch_workspace(state, &cmd->as.switch_workspace, plan);
       break;
     default:
     }
   }
-  return has_effect;
 }

src/core/policy.h

@@ -17,11 +17,8 @@ typedef struct policy_context_t {
  * @param ctx   策略上下文
  * @param event 需要翻译的事件
  * @param out   命令输出缓冲区，路由产生的命令追加到此处
- *
- * @return true     产生了至少一条需要执行的命令
- * @return false    产生了至少一条需要执行的命令
  */
-bool policy_route_event(
+void policy_route_event(
   const policy_context_t *ctx,
   const event_t *event,
   command_buffer_t *out
@@ -33,11 +30,8 @@ bool policy_route_event(
  * @param ctx               策略上下文
  * @param command_buffer    待应用的命令序列
  * @param plan              副作用累积器，记录后端需要执行的操作
- *
- * @return true     产生了至少一项后端副作用
- * @return false    无副作用产生
  */
-bool policy_apply_command(
+void policy_apply_command(
   const policy_context_t *ctx,
   const command_buffer_t *command_buffer,
   plan_t *plan

src/core/state.c

@@ -265,7 +265,8 @@ void state_output_set_workarea(
 bool state_output_set_current_workspace(
   state_t *state,
   output_id_t output_id,
-  workspace_id_t workspace_id
+  workspace_id_t workspace_id,
+  workspace_id_t *old_workspace_id
 ) {
   output_t *output = (output_t *)state_output_get(state, output_id);
   if (!output) return false;
@@ -274,6 +275,7 @@ bool state_output_set_current_workspace(
 
   if (output->current_workspace_id == workspace_id) return false;
 
+  if (old_workspace_id) *old_workspace_id = output->current_workspace_id;
   output->current_workspace_id = workspace_id;
   return true;
 }

src/core/state.h

@@ -126,13 +126,16 @@ void state_output_set_workarea(
  * @param state             状态实例指针
  * @param output_id         需要切换的当前 workspace 的 output 的 id
  * @param workspace_id      目标 workspace 的 id
+ * @param old_workspace_id  用于输出变更之前 output 显示的 workspace ，
+ *                          如果不关心，可以传 nullptr
  *
  * @return 若 workspace 需要切换返回 true ，否则返回 false
  */
 bool state_output_set_current_workspace(
   state_t *state,
   output_id_t output_id,
-  workspace_id_t workspace_id
+  workspace_id_t workspace_id,
+  workspace_id_t *old_workspace_id
 );
 size_t state_output_count(const state_t *state);
 bool state_output_valid(const state_t *state, output_id_t id);