From 263a59f6c54d9f71a1d89f10f8ef75953429c8da Mon Sep 17 00:00:00 2001
From: Cory McWilliams <cory@unprompted.com>
Date: Tue, 28 Dec 2021 17:44:48 +0000
Subject: [PATCH] Binary search promises.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3711 ed5197a5-7fde-0310-b194-c3ffbd925b24
---
 src/task.c | 75 +++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 24 deletions(-)

diff --git a/src/task.c b/src/task.c
index 4e4bc239..47f44456 100644
--- a/src/task.c
+++ b/src/task.c
@@ -58,7 +58,6 @@ typedef struct _promise_t promise_t;
 typedef struct _promise_t {
 	promiseid_t id;
 	JSValue values[3];
-	promise_t* next;
 } promise_t;
 
 typedef struct _tf_task_t {
@@ -1006,16 +1005,45 @@ tf_trace_t* tf_task_get_trace(tf_task_t* task)
 	return task->_trace;
 }
 
+static int _promise_compare(const void* a, const void* b)
+{
+	promiseid_t ida = (promiseid_t)(intptr_t)a;
+	const promise_t* pb = b;
+	return ida < pb->id ? -1 : pb->id < ida ? 1 : 0;
+}
+
+static int _insert_index(const void* key, const void* base, size_t count, size_t size, int (*compare)(const void*, const void*))
+{
+	int lower = 0;
+	int upper = count;
+	while (lower < upper && lower < (int)count)
+	{
+		int guess = (lower + upper) / 2;
+		int result = compare(key, ((char*)base) + size * guess);
+		if (result < 0)
+		{
+			upper = guess;
+		}
+		else if (result > 0)
+		{
+			lower = guess + 1;
+		}
+		else
+		{
+			return guess;
+		}
+	};
+	return lower;
+}
+
 static promise_t* _tf_task_find_promise(tf_task_t* task, promiseid_t id)
 {
-	for (promise_t* it = task->_promises; it; it = it->next)
+	if (!task->_promises)
 	{
-		if (it->id == id)
-		{
-			return it;
-		}
+		return NULL;
 	}
-	return NULL;
+	promise_t* it = bsearch((void*)(intptr_t)id, task->_promises, task->_promise_count, sizeof(promise_t), _promise_compare);
+	return it ? it : NULL;
 }
 
 static void _tf_task_trace_promises(tf_task_t* task)
@@ -1025,17 +1053,13 @@ static void _tf_task_trace_promises(tf_task_t* task)
 
 static void _tf_task_free_promise(tf_task_t* task, promiseid_t id)
 {
-	for (promise_t** it = &task->_promises; *it; it = &(*it)->next)
+	promise_t* it = bsearch((void*)(intptr_t)id, task->_promises, task->_promise_count, sizeof(promise_t), _promise_compare);
+	if (it)
 	{
-		if ((*it)->id == id)
-		{
-			promise_t* promise = *it;
-			*it = (*it)->next;
-			free(promise);
-			task->_promise_count--;
-			_tf_task_trace_promises(task);
-			break;
-		}
+		int index = it - task->_promises;
+		memmove(it, it + 1, sizeof(promise_t) * (task->_promise_count - index - 1));
+		task->_promise_count--;
+		_tf_task_trace_promises(task);
 	}
 }
 
@@ -1046,15 +1070,16 @@ promiseid_t tf_task_allocate_promise(tf_task_t* task)
 		promiseId = task->_nextPromise++;
 	} while (_tf_task_find_promise(task, promiseId));
 
-	promise_t* promise = malloc(sizeof(promise_t));
-	*promise = (promise_t)
+	promise_t promise =
 	{
 		.id = promiseId,
-		.next = task->_promises,
 		.values = { JS_NULL, JS_NULL, JS_NULL },
 	};
-	promise->values[0] = JS_NewPromiseCapability(task->_context, &promise->values[1]);
-	task->_promises = promise;
+	promise.values[0] = JS_NewPromiseCapability(task->_context, &promise.values[1]);
+	int index = _insert_index((void*)(intptr_t)promiseId, task->_promises, task->_promise_count, sizeof(promise_t), _promise_compare);
+	task->_promises = realloc(task->_promises, sizeof(promise_t) * (task->_promise_count + 1));
+	memmove(task->_promises + index, task->_promises + index + 1, sizeof(promise_t) * (task->_promise_count - index));
+	task->_promises[index] = promise;
 	task->_promise_count++;
 	_tf_task_trace_promises(task);
 	return promiseId;
@@ -1327,10 +1352,12 @@ void tf_task_destroy(tf_task_t* task)
 	{
 		JS_FreeValue(task->_context, tf_taskstub_get_task_object(task->_parent));
 	}
-	while (task->_promises)
+	while (task->_promise_count)
 	{
-		tf_task_reject_promise(task, task->_promises->id, JS_NULL);
+		tf_task_reject_promise(task, task->_promises[task->_promise_count - 1].id, JS_NULL);
 	}
+	free(task->_promises);
+	task->_promises = NULL;
 	JS_FreeValue(task->_context, task->_requires);
 	JS_FreeValue(task->_context, task->_loadedFiles);
 	while (task->_scriptExports)