tildefriends/src/task.c

#include "task.h"

#include "bcrypt.h"
#include "database.h"
#include "file.h"
#include "packetstream.h"
#include "serialize.h"
#include "socket.h"
#include "ssb.h"
#include "ssb.qjs.h"
#include "taskstub.h"
#include "tlscontextwrapper.h"
#include "trace.h"

#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <uv.h>

#include <sqlite3.h>

#include "quickjs.h"
#include "quickjs-libc.h"

#ifdef _WIN32
static const int STDIN_FILENO = 0;
#else
#include <unistd.h>
#endif

static const char* k_version = "1.0";

static JSClassID _import_class_id;
static int _count;

static void _task_timeoutCallback(uv_timer_t* handle);

typedef struct _export_record_t export_record_t;
typedef struct _import_record_t import_record_t;

typedef struct _task_child_node_t task_child_node_t;

typedef struct _task_child_node_t {
	taskid_t id;
	tf_taskstub_t* stub;
	task_child_node_t* next;
} task_child_node_t;

typedef struct _script_export_t script_export_t;

typedef struct _script_export_t {
	const char* name;
	JSValue value;
	script_export_t* next;
} script_export_t;

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 {
	taskid_t _nextTask;
	task_child_node_t* _children;
	int _child_count;

	tf_taskstub_t* _stub;
	tf_taskstub_t* _parent;
	const char* _path;

	script_export_t* _scriptExports;

	bool _trusted;
	bool _killed;
	int32_t _exitCode;
	char _scriptName[256];

	JSRuntime* _runtime;
	JSContext* _context;

	sqlite3* _db;

	tf_ssb_t* _ssb;

	tf_trace_t* _trace;

	promise_t* _promises;
	int _promise_count;
	promiseid_t _nextPromise;
	uv_loop_t* _loop;

	export_record_t* _exports;
	int _export_count;
	exportid_t _nextExport;

	import_record_t* _imports;
	int _import_count;
	JSValue _requires;
	JSValue _loadedFiles;

	int _ssb_port;
	int _http_port;
	int _https_port;
	const char* _db_path;
	const char* _secrets_path;
} tf_task_t;

typedef struct _export_record_t {
	exportid_t _export_id;
	taskid_t _taskid;
	JSValue _function;
	int _useCount;
	export_record_t* _next;
} export_record_t;

static void _export_record_ref(export_record_t* export) {
	export->_useCount++;
}

static bool _export_record_release(export_record_t* export) {
	return --export->_useCount == 0;
}

static JSValue _tf_task_version(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _tf_task_utf8Decode(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _tf_task_get_parent(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _tf_task_print(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _tf_task_exit(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _tf_task_sandbox_require(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _tf_task_trace(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);
static JSValue _tf_task_getFile(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv);

static void _tf_task_sendPromiseMessage(tf_task_t* from, tf_taskstub_t* to, tf_task_message_t messageType, promiseid_t promise, JSValue result);
static void _tf_task_sendPromiseResolve(tf_task_t* from, tf_taskstub_t* to, promiseid_t promise, JSValue result);
static void _tf_task_sendPromiseReject(tf_task_t* from, tf_taskstub_t* to, promiseid_t promise, JSValue result);

static void _tf_task_sendPromiseExportMessage(tf_task_t* from, tf_taskstub_t* to, tf_task_message_t messageType, promiseid_t promiseId, exportid_t exportId, JSValue result);
static JSValue _tf_task_executeSource(tf_task_t* task, const char* source, const char* name);
static tf_taskstub_t* _tf_task_get_stub(tf_task_t* task, taskid_t id);
static void _tf_task_release_export(tf_taskstub_t* stub, exportid_t exportId);

typedef struct _import_record_t {
	JSValue _function;
	exportid_t _export;
	taskid_t _task;
	tf_task_t* _owner;
	int _useCount;
	import_record_t* _next;
} import_record_t;

static void _tf_task_trace_imports(tf_task_t* task)
{
	tf_trace_counter(task->_trace, "imports", 1, (const char*[]) { "count" }, (int64_t[]) { task->_import_count });
}

static void _import_record_release(import_record_t* import) {
	JSContext* context = import->_owner->_context;
	if (--import->_useCount > 0) {
		return;
	}

	JS_SetOpaque(import->_function, NULL);
	JS_FreeValue(context, import->_function);
	import->_function = JS_UNDEFINED;
	_tf_task_release_export(_tf_task_get_stub(import->_owner, import->_task), import->_export);

	for (import_record_t** it = &import->_owner->_imports;
		*it;
		it = &(*it)->_next) {
		if (*it == import) {
			*it = import->_next;
			import->_owner->_import_count--;
			_tf_task_trace_imports(import->_owner);
			import->_next = NULL;
			break;
		}
	}

	free(import);
}

static void _import_record_release_for_task(tf_task_t* task, taskid_t task_id)
{
	bool any = false;
	import_record_t** next = NULL;
	for (import_record_t** it = &task->_imports;
		*it;
		it = next) {
		next = &(*it)->_next;
		if ((*it)->_task == task_id) {
			import_record_t* import = *it;
			_import_record_release(import);
			next = it;
			any = true;
		}
	}

	if (any) {
		_tf_task_trace_imports(task);
	}
}

static void _tf_task_trace_exports(tf_task_t* task)
{
	tf_trace_counter(task->_trace, "exports", 1, (const char*[]) { "count" }, (int64_t[]) { task->_export_count });
}

static void _export_record_release_for_task(tf_task_t* task, taskid_t task_id)
{
	bool any = false;
	export_record_t** next = NULL;
	for (export_record_t** it = &task->_exports;
		*it;
		it = next) {
		next = &(*it)->_next;
		if ((*it)->_taskid == task_id) {
			export_record_t* export = *it;
			if (_export_record_release(export)) {
				*it = export->_next;
				JS_FreeValue(task->_context, export->_function);
				free(export);
				task->_export_count--;
				_tf_task_trace_exports(task);
				next = it;
				any = true;
			}
		}
	}

	if (any) {
		_tf_task_trace_exports(task);
	}
}

static void _tf_task_send_error_to_parent(tf_task_t* task, JSValue error) {
	if (task->_parent) {
		void* buffer = NULL;
		size_t size = 0;
		tf_serialize_store(task, task->_parent, &buffer, &size, error);
		tf_packetstream_send(tf_taskstub_get_stream(task->_parent), kTaskError, buffer, size);
		free(buffer);
	}
}

void tf_task_report_error(tf_task_t* task, JSValue error) {
	JSContext* context = task->_context;
	if (JS_IsError(context, error)) {
		const char* value = JS_ToCString(context, error);
		printf("ERROR: %s\n", value);
		JS_FreeCString(context, value);

		JSValue stack = JS_GetPropertyStr(context, error, "stack");
		if (!JS_IsUndefined(stack)) {
			const char* stack_str = JS_ToCString(context, stack);
			printf("%s\n", stack_str);
			JS_FreeCString(context, stack_str);
		}
		JS_FreeValue(context, stack);

		_tf_task_send_error_to_parent(task, error);
	} else if (JS_IsException(error)) {
		error = JS_GetException(context);
		const char* value = JS_ToCString(context, error);
		printf("Exception: %s\n", value);
		JS_FreeCString(context, value);
		_tf_task_send_error_to_parent(task, error);
	}
}

static const char* _task_loadFile(const char* fileName) {
	char* result = NULL;
	FILE* file = fopen(fileName, "rb");
	if (file) {
		fseek(file, 0, SEEK_END);
		long fileSize = ftell(file);
		fseek(file, 0, SEEK_SET);
		result = malloc(fileSize + 1);
		fread(result, 1, fileSize, file);
		result[fileSize] = '\0';
		fclose(file);
	}
	return result;
}

JSValue _tf_task_print(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	tf_task_t* task = JS_GetContextOpaque(context);
	printf("Task[%p:%s]>", task, task->_scriptName);
	for (int i = 0; i < argc; ++i) {
		if (JS_IsNull(argv[i])) {
			printf(" null");
		} else {
			const char* value = JS_ToCString(task->_context, argv[i]);
			printf(" %s", value);
			JS_FreeCString(task->_context, value);
		}
	}
	printf("\n");
	return JS_NULL;
}

typedef struct _timeout_t {
	tf_task_t* _task;
	JSValue _callback;
} timeout_t;

static JSValue _task_setTimeout(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	tf_task_t* task = JS_GetContextOpaque(context);

	timeout_t* timeout = malloc(sizeof(timeout_t));
	*timeout = (timeout_t) {
		._task = task,
		._callback = JS_DupValue(context, argv[0]),
	};

	uv_timer_t* timer = malloc(sizeof(uv_timer_t));
	memset(timer, 0, sizeof(uv_timer_t));
	uv_timer_init(task->_loop, timer);
	timer->data = timeout;

	int64_t duration;
	JS_ToInt64(task->_context, &duration, argv[1]);
	uv_timer_start(timer, _task_timeoutCallback, duration, 0);
	return JS_NULL;
}

static void _handle_closed(uv_handle_t* handle)
{
	free(handle);
}

static void _task_timeoutCallback(uv_timer_t* handle) {
	timeout_t* timeout = handle->data;
	tf_trace_begin(timeout->_task->_trace, "_task_timeoutCallback");
	JSValue result = JS_Call(
		timeout->_task->_context,
		timeout->_callback,
		JS_NULL,
		0,
		NULL);
	tf_task_report_error(timeout->_task, result);
	JS_FreeValue(timeout->_task->_context, result);
	tf_task_run_jobs(timeout->_task);
	tf_trace_end(timeout->_task->_trace);
	free(timeout);
	uv_close((uv_handle_t*)handle, _handle_closed);
}

JSValue _tf_task_exit(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	tf_task_t* task = JS_GetContextOpaque(context);
	int exitCode = 0;
	JS_ToInt32(task->_context, &exitCode, argv[0]);
	exit(exitCode);
	return JS_UNDEFINED;
}

int tf_task_execute(tf_task_t* task, const char* fileName) {
	bool executed = false;

	tf_trace_begin(task->_trace, "tf_task_execute");
	const char* source = _task_loadFile(fileName);
	printf("Running script %s\n", fileName);
	if (!*task->_scriptName) {
		strncpy(task->_scriptName, fileName, sizeof(task->_scriptName) - 1);
	}
	if (!task->_path) {
		char* path = strdup(fileName);
		char* slash = strrchr(path, '/');
		if (slash) {
			*slash = '\0';
			task->_path = strdup(path);
		} else {
			task->_path = strdup("./");
		}
		free(path);
	}
	if (source) {
		JSValue result = JS_Eval(task->_context, source, strlen(source), fileName, 0);
		tf_task_report_error(task, result);
		if (!JS_IsError(task->_context, result) && !JS_IsException(result)) {
			executed = true;
		}
		JS_FreeValue(task->_context, result);
		tf_task_run_jobs(task);
		free((void*)source);
	} else {
		printf("Failed to load file: %s.\n", fileName);
	}
	tf_trace_end(task->_trace);
	return executed;
}

static tf_taskstub_t* _tf_task_get_stub(tf_task_t* task, taskid_t id) {
	if (id == k_task_parent_id) {
		return task->_parent;
	}

	for (task_child_node_t* node = task->_children; node; node = node->next) {
		if (node->id == id) {
			return node->stub;
		}
	}
	return NULL;
}


static JSValue _import_call(JSContext* context, JSValueConst func_obj, JSValueConst this_val, int argc, JSValueConst *argv, int flags)
{
	import_record_t* import = JS_GetOpaque(func_obj, _import_class_id);
	if (!import) {
		return JS_ThrowInternalError(context, "Invoking a function that has been released.");
	}
	import->_useCount++;

	JSValue array = JS_NewArray(context);
	JS_SetPropertyUint32(context, array, 0, JS_DupValue(context, this_val));
	for (int i = 0; i < argc; ++i) {
		JS_SetPropertyUint32(context, array, i + 1, JS_DupValue(context, argv[i]));
	}

	tf_task_t* sender = JS_GetContextOpaque(context);
	JSValue result;
	tf_taskstub_t* recipient = _tf_task_get_stub(sender, import->_task);
	if (recipient) {
		promiseid_t promise = tf_task_allocate_promise(sender);
		_tf_task_sendPromiseExportMessage(sender, recipient, kInvokeExport, promise, import->_export, array);
		result = tf_task_get_promise(sender, promise);
	} else {
		result = JS_ThrowInternalError(context, "Invoking a function on a nonexistent task.");
	}
	JS_FreeValue(context, array);
	return result;
}

static export_record_t* _task_get_export(tf_task_t* task, exportid_t export_id) {
	for (export_record_t* it = task->_exports; it; it = it->_next) {
		if (it->_export_id == export_id) {
			return it;
		}
	}
	return NULL;
}

JSValue _task_invokeExport_internal(tf_taskstub_t* from, tf_task_t* to, exportid_t exportId, const char* buffer, size_t size) {
	JSValue result = JS_NULL;
	export_record_t* export = _task_get_export(to, exportId);
	if (export) {
		JSValue arguments = tf_serialize_load((tf_task_t*)to, from, buffer, size);
		JSValue* argument_array = NULL;
		JSValue length_val = JS_GetPropertyStr(to->_context, arguments, "length");
		int length;
		JSValue this_val = JS_NULL;
		if (JS_ToInt32(to->_context, &length, length_val) == 0) {
			if (length > 0) {
				this_val = JS_GetPropertyUint32(to->_context, arguments, 0);
				argument_array = alloca(sizeof(JSValue) * (length - 1));
			}
			for (int i = 1; i < length; ++i) {
				argument_array[i - 1] = JS_GetPropertyUint32(to->_context, arguments, i);
			}
		}
		JSValue function = export->_function;
		JSPropertyDescriptor desc;
		const char* name = NULL;
		JSAtom atom = JS_NewAtom(to->_context, "name");
		if (JS_GetOwnProperty(to->_context, &desc, function, atom) == 1) {
			name = JS_ToCString(to->_context, desc.value);
			JS_FreeValue(to->_context, desc.value);
		}
		JS_FreeAtom(to->_context, atom);
		tf_trace_begin(to->_trace, name ? name : "_task_invokeExport_internal");
		if (name) {
			JS_FreeCString(to->_context, name);
		}
		result = JS_Call(to->_context, function, this_val, length - 1, argument_array);
		tf_trace_end(to->_trace);
		tf_task_report_error(to, result);
		tf_task_run_jobs(to);
	} else {
		printf("%s: That's not an export we have (exportId=%d, exports=%d)\n", to->_scriptName, exportId, to->_export_count);
	}
	tf_packetstream_send(tf_taskstub_get_stream(from), kReleaseImport, (void*)&exportId, sizeof(exportId));
	return result;
}

static JSValue _invokeThen(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv, int magic, JSValue* func_data) {
	taskid_t taskid = 0;
	JS_ToInt32(context, &taskid, func_data[0]);
	tf_task_t* from = JS_GetContextOpaque(context);
	tf_taskstub_t* to = _tf_task_get_stub(from, taskid);
	promiseid_t promiseid = 0;
	JS_ToInt32(context, &promiseid, func_data[1]);
	_tf_task_sendPromiseMessage(from, to, kResolvePromise, promiseid, argv[0]);
	return JS_DupValue(context, this_val);
}

static JSValue _invokeCatch(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv, int magic, JSValue* func_data) {
	taskid_t taskid = 0;
	JS_ToInt32(context, &taskid, func_data[0]);
	tf_task_t* from = JS_GetContextOpaque(context);
	tf_taskstub_t* to = _tf_task_get_stub(from, taskid);
	promiseid_t promiseid = 0;
	JS_ToInt32(context, &promiseid, func_data[1]);
	_tf_task_sendPromiseMessage(from, to, kRejectPromise, promiseid, argv[0]);
	return JS_DupValue(context, this_val);
}

static void _forward_promise(tf_task_t* from, tf_taskstub_t* to, promiseid_t promise, JSValue result) {
	// We're not going to serialize/deserialize a promise...
	JSValue data[] = {
		JS_NewInt32(from->_context, tf_taskstub_get_id(to)),
		JS_NewInt32(from->_context, promise),
	};
	JSValue promise_then = JS_GetPropertyStr(from->_context, result, "then");
	JSValue promise_catch = JS_GetPropertyStr(from->_context, result, "catch");

	JSValue then_handler = JS_NewCFunctionData(from->_context, _invokeThen, 0, 0, 2, data);
	JSValue catch_handler = JS_NewCFunctionData(from->_context, _invokeCatch, 0, 0, 2, data);

	JSValue error = JS_Call(from->_context, promise_then, result, 1, &then_handler);
	tf_task_report_error(from, error);
	JS_FreeValue(from->_context, error);
	error = JS_Call(from->_context, promise_catch, result, 1, &catch_handler);
	tf_task_report_error(from, error);
	JS_FreeValue(from->_context, error);

	tf_task_run_jobs(from);
}

static void _tf_task_sendPromiseResolve(tf_task_t* from, tf_taskstub_t* to, promiseid_t promise, JSValue result) {
	JSValue global = JS_GetGlobalObject(from->_context);
	JSValue promiseType = JS_GetPropertyStr(from->_context, global, "Promise");
	JS_FreeValue(from->_context, global);
	if (JS_IsInstanceOf(from->_context, result, promiseType)) {
		_forward_promise(from, to, promise, result);
	} else {
		_tf_task_sendPromiseMessage(from, to, kResolvePromise, promise, result);
	}
}

static void _tf_task_sendPromiseReject(tf_task_t* from, tf_taskstub_t* to, promiseid_t promise, JSValue result) {
	JSValue global = JS_GetGlobalObject(from->_context);
	JSValue promiseType = JS_GetPropertyStr(from->_context, global, "Promise");
	JS_FreeValue(from->_context, global);
	if (JS_IsInstanceOf(from->_context, result, promiseType)) {
		_forward_promise(from, to, promise, result);
	} else {
		_tf_task_sendPromiseMessage(from, to, kRejectPromise, promise, result);
	}
}

static void _tf_task_sendPromiseMessage(tf_task_t* from, tf_taskstub_t* to, tf_task_message_t messageType, promiseid_t promise, JSValue result) {
	if (to) {
		void* buffer;
		size_t size;
		tf_serialize_store(from, to, &buffer, &size, result);

		char* copy = (char*)malloc(sizeof(promise) + size);
		memcpy(copy, &promise, sizeof(promise));
		memcpy(copy + sizeof(promise), buffer, size);
		tf_packetstream_send(tf_taskstub_get_stream(to), messageType, copy, size + sizeof(promise));
		free(buffer);
		free(copy);
	} else {
		printf("Sending to a NULL task.\n");
	}
}

static void _tf_task_sendPromiseExportMessage(tf_task_t* from, tf_taskstub_t* to, tf_task_message_t messageType, promiseid_t promise, exportid_t exportId, JSValue result) {
	void* buffer;
	size_t size;
	tf_serialize_store(from, to, &buffer, &size, result);
	char* copy = (char*)malloc(sizeof(promise) + sizeof(exportId) + size);
	memcpy(copy, &promise, sizeof(promise));
	memcpy(copy + sizeof(promise), &exportId, sizeof(exportId));
	memcpy(copy + sizeof(promise) + sizeof(exportId), buffer, size);
	tf_packetstream_send(tf_taskstub_get_stream(to), messageType, copy, sizeof(promise) + sizeof(exportId) + size);
	free(buffer);
	free(copy);
}

JSValue _tf_task_get_parent(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	tf_task_t* task = JS_GetContextOpaque(context);
	return task->_parent ? tf_taskstub_get_task_object(task->_parent) : JS_UNDEFINED;
}

static JSValue _tf_task_version(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	tf_task_t* task = JS_GetContextOpaque(context);
	return JS_NewString(task->_context, k_version);
}

exportid_t tf_task_export_function(tf_task_t* task, tf_taskstub_t* to, JSValue function)
{
	export_record_t* export = NULL;

	for (export_record_t* it = task->_exports; it; it = it->_next) {
		if (JS_VALUE_GET_PTR(it->_function) == JS_VALUE_GET_PTR(function) &&
			it->_taskid == tf_taskstub_get_id(to)) {
			export = it;
			break;
		}
	}

	if (!export) {
		int id = -1;
		do {
			id = task->_nextExport++;
		} while (_task_get_export(task, id));

		export = malloc(sizeof(export_record_t));
		*export = (export_record_t) {
			._export_id = id,
			._taskid = tf_taskstub_get_id(to),
			._function = JS_DupValue(task->_context, function),
			._next = task->_exports,
		};
		task->_exports = export;
		task->_export_count++;
		_tf_task_trace_exports(task);
	}

	if (export) {
		_export_record_ref(export);
	}

	return export ? export->_export_id : -1;
}

static void _tf_task_release_export(tf_taskstub_t* stub, exportid_t exportId)
{
	if (stub) {
		tf_packetstream_t* stream = tf_taskstub_get_stream(stub);
		if (stream) {
			tf_packetstream_send(stream, kReleaseExport, (void*)&exportId, sizeof(exportId));
		}
	}
}

static JSValue _tf_task_trace(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv){
	tf_task_t* task = JS_GetContextOpaque(context);
	if (!task->_trace) {
		return JS_UNDEFINED;
	}

	char* trace = tf_trace_export(task->_trace);
	JSValue result = JS_NewString(context, trace);
	free(trace);
	return result;
}

static JSValue _tf_task_getFile(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv)
{
	tf_task_t* task = JS_GetContextOpaque(context);
	const char* name = JS_ToCString(context, argv[0]);
	JSValue result = JS_GetPropertyStr(context, task->_loadedFiles, name);
	JS_FreeCString(context, name);
	return result;
}

void tf_task_on_receive_packet(int packetType, const char* begin, size_t length, void* userData)
{
	tf_taskstub_t* stub = userData;
	tf_taskstub_t* from = stub;
	tf_task_t* to = tf_taskstub_get_owner(stub);
	tf_trace_begin(to->_trace, "tf_task_on_receive_packet");

	switch (packetType) {
	case kInvokeExport:
		{
			promiseid_t promise;
			exportid_t exportId;
			memcpy(&promise, begin, sizeof(promise));
			memcpy(&exportId, begin + sizeof(promise), sizeof(exportId));

			JSValue result = _task_invokeExport_internal(from, to, exportId, begin + sizeof(promiseid_t) + sizeof(exportid_t), length);
			if (JS_IsException(result)) {
				_tf_task_sendPromiseReject(to, from, promise, result);
			} else {
				_tf_task_sendPromiseResolve(to, from, promise, result);
			}
		}
		break;
	case kResolvePromise:
	case kRejectPromise:
		{
			JSValue arg = JS_UNDEFINED;
			promiseid_t promise;
			memcpy(&promise, begin, sizeof(promiseid_t));
			if (length > sizeof(promiseid_t)) {
				arg = tf_serialize_load((tf_task_t*)to, from, begin + sizeof(promiseid_t), length - sizeof(promiseid_t));
			}
			if (packetType == kResolvePromise) {
				tf_task_resolve_promise(to, promise, arg);
			} else {
				tf_task_reject_promise(to, promise, arg);
			}
			JS_FreeValue(to->_context, arg);
		}
		break;
	case kReleaseExport:
		{
			assert(length == sizeof(exportid_t));
			exportid_t exportId;
			memcpy(&exportId, begin, sizeof(exportId));
			for (export_record_t** it = &to->_exports; *it; it = &(*it)->_next) {
				export_record_t* export = *it;
				if (export->_export_id == exportId &&
					export->_taskid == tf_taskstub_get_id(from)) {
					if (_export_record_release(export)) {
						*it = export->_next;
						JS_FreeValue(to->_context, export->_function);
						free(export);
						to->_export_count--;
						_tf_task_trace_exports(to);
					}
					break;
				}
			}
		}
		break;
	case kReleaseImport:
		{
			assert(length == sizeof(exportid_t));
			exportid_t exportId;
			memcpy(&exportId, begin, sizeof(exportId));
			for (import_record_t* it = to->_imports; it; it = it->_next) {
				if (it->_task == tf_taskstub_get_id(from) && it->_export == exportId) {
					_import_record_release(it);
					break;
				}
			}
		}
		break;
	case kSetRequires:
		to->_requires = tf_serialize_load((tf_task_t*)to, from, begin, length);
		break;
	case kLoadFile:
		{
			JSValue args = tf_serialize_load((tf_task_t*)to, from, begin, length);
			JSValue key = JS_GetPropertyUint32(to->_context, args, 0);
			JSValue content = JS_GetPropertyUint32(to->_context, args, 1);
			const char* name = JS_ToCString(to->_context, key);
			JS_SetPropertyStr(to->_context, to->_loadedFiles, name, JS_DupValue(to->_context, content));
			JS_FreeCString(to->_context, name);
			JS_FreeValue(to->_context, key);
			JS_FreeValue(to->_context, content);
			JS_FreeValue(to->_context, args);
		}
		break;
	case kActivate:
		tf_task_activate(to);
		break;
	case kExecute:
		{
			assert(length >= sizeof(promiseid_t));
			promiseid_t promise;
			memcpy(&promise, begin, sizeof(promiseid_t));
			JSValue value = tf_serialize_load((tf_task_t*)to, from, begin + sizeof(promiseid_t), length - sizeof(promiseid_t));
			JSValue source = JS_GetPropertyStr(to->_context, value, "source");
			JSValue name_val = JS_GetPropertyStr(to->_context, value, "name");
			const char* name = JS_ToCString(to->_context, name_val);
			JS_FreeValue(to->_context, name_val);
			JS_FreeValue(to->_context, value);

			JSValue utf8 = _tf_task_utf8Decode(to->_context, JS_NULL, 1, &source);
			const char* source_str = JS_ToCString(to->_context, utf8);
			JS_FreeValue(to->_context, utf8);
			_tf_task_executeSource(to, source_str, name);
			JS_FreeCString(to->_context, source_str);
			JS_FreeCString(to->_context, name);
			_tf_task_sendPromiseResolve(to, from, promise, JS_UNDEFINED);
		}
		break;
	case kKill:
		exit(1);
		break;
	case kSetImports:
		{
			JSValue global = JS_GetGlobalObject(to->_context);
			JSValue imports = tf_serialize_load((tf_task_t*)to, from, begin, length);

			JSPropertyEnum* ptab;
			uint32_t plen;
			JS_GetOwnPropertyNames(to->_context, &ptab, &plen, imports, JS_GPN_STRING_MASK);
			for (uint32_t i = 0; i < plen; ++i) {
				JSPropertyDescriptor desc;
				if (JS_GetOwnProperty(to->_context, &desc, imports, ptab[i].atom) == 1) {
					JS_SetProperty(to->_context, global, ptab[i].atom, desc.value);
				}
				JS_FreeAtom(to->_context, ptab[i].atom);
			}
			js_free(to->_context, ptab);

			JS_SetPropertyStr(to->_context, global, "imports", imports);
			JS_FreeValue(to->_context, global);
		}
		break;
	case kGetExports:
		{
			promiseid_t promise;
			assert(length >= sizeof(promise));
			memcpy(&promise, begin, sizeof(promiseid_t));
			JSValue global = JS_GetGlobalObject(to->_context);
			JSValue exportObject = JS_GetPropertyStr(to->_context, global, "exports");
			_tf_task_sendPromiseResolve(to, from, promise, exportObject);
			JS_FreeValue(to->_context, exportObject);
			JS_FreeValue(to->_context, global);
		}
		break;
	case kTaskError:
		{
			JSValue error = tf_serialize_load((tf_task_t*)to, from, begin, length);
			tf_taskstub_on_error(from, error);
			JS_FreeValue(to->_context, error);
		}
		break;
	}
	tf_trace_end(to->_trace);
}

static const char* _tf_task_resolveRequire(tf_task_t* task, const char* require) {
	printf("Looking in %s for %s\n", task->_path, require);
	if (strstr(require, "..") || strstr(require, "/") || strstr(require, "\\")) {
		return NULL;
	}
	char test[1024];
	snprintf(test, sizeof(test), "%s/%s%s", task->_path, require, strstr(require, ".js") ? "" : ".js");
	printf("Testing %s\n", test);
	uv_fs_t request;
	if (uv_fs_access(task->_loop, &request, test, R_OK, 0) == 0) {
		return strdup(test);
	}
	return NULL;
}

static script_export_t* _task_find_script_export(tf_task_t* task, const char* path) {
	for (script_export_t* it = task->_scriptExports; it; it = it->next) {
		if (strcmp(it->name, path) == 0) {
			return it;
		}
	}
	return NULL;
}

JSValue _tf_task_require(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	JSValue result = JS_NULL;
	tf_task_t* task = JS_GetContextOpaque(context);
	tf_trace_begin(task->_trace, "_tf_task_require");
	const char* in_path = JS_ToCString(context, argv[0]);
	if (in_path) {
		const char* path = _tf_task_resolveRequire(task, in_path);
		if (!path) {
			result = JS_ThrowReferenceError(task->_context, "require(): Unable to resolve module: %s.", in_path);
		} else {
			script_export_t* it = _task_find_script_export(task, path);
			if (it) {
				result = JS_DupValue(task->_context, it->value);
				free((void*)path);
			} else {
				JSValue exports = JS_NewObject(task->_context);
				script_export_t* export = malloc(sizeof(script_export_t));
				*export = (script_export_t) {
					.name = path,
					.value = JS_DupValue(task->_context, exports),
					.next = task->_scriptExports,
				};
				task->_scriptExports = export;
				const char* source = _task_loadFile(path);
				printf("Requiring script %s\n", path);
				if (source) {
					JSValue global = JS_GetGlobalObject(task->_context);
					JSValue oldExports = JS_GetPropertyStr(task->_context, global, "exports");
					JS_SetPropertyStr(task->_context, global, "exports", JS_DupValue(task->_context, exports));
					JSValue eval = JS_Eval(task->_context, source, strlen(source), path, 0);
					tf_task_report_error(task, eval);
					tf_task_run_jobs(task);
					if (JS_IsError(task->_context, eval) ||
						JS_IsException(eval)) {
						result = JS_DupValue(task->_context, eval);
					} else {
						result = JS_DupValue(task->_context, exports);
					}
					JS_FreeValue(task->_context, eval);
					JS_SetPropertyStr(task->_context, global, "exports", oldExports);
					JS_FreeValue(task->_context, global);
					free((void*)source);
				} else {
					printf("Failed to load %s.\n", path);
				}
				JS_FreeValue(task->_context, exports);
			}
		}
	} else {
		result = JS_ThrowReferenceError(task->_context, "require(): No module specified.");
	}
	JS_FreeCString(context, in_path);
	tf_trace_end(task->_trace);
	return result;
}

static JSValue _tf_task_executeSource(tf_task_t* task, const char* source, const char* name) {
	tf_trace_begin(task->_trace, "_tf_task_executeSource");
	JSValue result = JS_Eval(task->_context, source, strlen(source), name, 0);
	tf_task_report_error(task, result);
	if (!*task->_scriptName) {
		snprintf(task->_scriptName, sizeof(task->_scriptName), "%s", name);
	}
	tf_task_run_jobs(task);
	tf_trace_end(task->_trace);
	return result;
}

JSValue _tf_task_sandbox_require(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	tf_task_t* task = JS_GetContextOpaque(context);

	if (JS_IsObject(task->_loadedFiles)) {
		const char* name = JS_ToCString(context, argv[0]);
		script_export_t* it = _task_find_script_export(task, name);
		if (it) {
			return it->value;
		} else {
			JSValue exports = JS_NewObject(context);
			const char* name = JS_ToCString(context, argv[0]);
			JSValue value = JS_GetPropertyStr(context, task->_loadedFiles, name);
			size_t length;
			uint8_t* array = tf_try_get_array_buffer(context, &length, value);
			if (array) {
				char* source = malloc(length + 1);
				memcpy(source, array, length);
				source[length] = '\0';
				JSValue global = JS_GetGlobalObject(context);
				JSValue oldExports = JS_GetPropertyStr(context, global, "exports");
				JS_SetPropertyStr(context, global, "exports", JS_DupValue(context, exports));
				JSValue result = JS_Eval(context, source, length, name, 0);
				tf_task_report_error(task, result);
				JS_SetPropertyStr(context, global, "exports", oldExports);
				JS_FreeValue(context, global);
				tf_task_run_jobs(task);
				free(source);
				return exports;
			} else if (JS_IsString(value)) {
				size_t length;
				const char* source = JS_ToCStringLen(context, &length, value);
				JSValue global = JS_GetGlobalObject(context);
				JSValue oldExports = JS_GetPropertyStr(context, global, "exports");
				JS_SetPropertyStr(context, global, "exports", JS_DupValue(context, exports));
				JSValue result = JS_Eval(context, source, length, name, 0);
				tf_task_report_error(task, result);
				JS_SetPropertyStr(context, global, "exports", oldExports);
				JS_FreeValue(context, global);
				tf_task_run_jobs(task);
				return exports;
			} else {
				return JS_ThrowInternalError(context, "Failed to load %s %d %d %d.", name, JS_IsNull(value), JS_IsUndefined(value), JS_IsException(value));
			}
		}
	}

	return JS_UNDEFINED;
}

static JSValue _utf8Decode(JSContext* context, uint8_t* data, size_t length) {
	return JS_NewStringLen(context, (const char*)data, length);
}

static JSValue _tf_task_utf8Decode(JSContext* context, JSValueConst this_val, int argc, JSValueConst* argv) {
	JSValue result = JS_NULL;
	size_t length;
	if (JS_IsString(argv[0])) {
		result = JS_DupValue(context, argv[0]);
	} else {
		uint8_t* array = tf_try_get_array_buffer(context, &length, argv[0]);
		if (array) {
			result = _utf8Decode(context, array, length);
		} else {
			size_t offset;
			size_t element_size;
			JSValue buffer = tf_try_get_typed_array_buffer(context, argv[0], &offset, &length, &element_size);
			size_t size;
			if (!JS_IsException(buffer)) {
				array = tf_try_get_array_buffer(context, &size, buffer);
				if (array) {
					result = _utf8Decode(context, array, size);
				}
			}
			JS_FreeValue(context, buffer);
		}
	}
	return result;
}

uv_loop_t* tf_task_get_loop(tf_task_t* task) {
	return task->_loop;
}

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 (it->id == id) {
			return it;
		}
	}
	return NULL;
}

static void _tf_task_trace_promises(tf_task_t* task)
{
	tf_trace_counter(task->_trace, "promises", 1, (const char*[]) { "count" }, (int64_t[]) { task->_promise_count });
}

static void _tf_task_free_promise(tf_task_t* task, promiseid_t id) {
	for (promise_t** it = &task->_promises; *it; it = &(*it)->next) {
		if ((*it)->id == id) {
			promise_t* promise = *it;
			*it = (*it)->next;
			free(promise);
			task->_promise_count--;
			_tf_task_trace_promises(task);
			break;
		}
	}
}

promiseid_t tf_task_allocate_promise(tf_task_t* task) {
	promiseid_t promiseId;
	do {
		promiseId = task->_nextPromise++;
	} while (_tf_task_find_promise(task, promiseId));

	promise_t* promise = malloc(sizeof(promise_t));
	*promise = (promise_t) {
		.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;
	task->_promise_count++;
	_tf_task_trace_promises(task);
	return promiseId;
}

void tf_task_resolve_promise(tf_task_t* task, promiseid_t promise, JSValue value) {
	promise_t* it = _tf_task_find_promise(task, promise);
	if (it) {
		JSValue result = JS_Call(task->_context, it->values[1], JS_UNDEFINED, 1, &value);
		tf_task_report_error(task, result);
		JS_FreeValue(task->_context, it->values[1]);
		JS_FreeValue(task->_context, it->values[2]);
		JS_FreeValue(task->_context, result);
		_tf_task_free_promise(task, promise);
		tf_task_run_jobs(task);
	} else {
		printf("Didn't find promise %d to resolve.\n", promise);
		abort();
	}
}

void tf_task_reject_promise(tf_task_t* task, promiseid_t promise, JSValue value) {
	promise_t* it = _tf_task_find_promise(task, promise);
	if (it) {
		JSValue result = JS_Call(task->_context, it->values[2], JS_UNDEFINED, 1, &value);
		tf_task_report_error(task, result);
		JS_FreeValue(task->_context, it->values[1]);
		JS_FreeValue(task->_context, it->values[2]);
		JS_FreeValue(task->_context, result);
		_tf_task_free_promise(task, promise);
		tf_task_run_jobs(task);
	}
}

JSValue tf_task_get_promise(tf_task_t* task, promiseid_t promise) {
	promise_t* it = _tf_task_find_promise(task, promise);
	return it ? it->values[0] : JS_NULL;
}

static void _tf_task_trace_children(tf_task_t* task)
{
	tf_trace_counter(task->_trace, "child_tasks", 1, (const char*[]) { "count" }, (int64_t[]) { task->_child_count });
}

taskid_t tf_task_allocate_task_id(tf_task_t* task, tf_taskstub_t* stub) {
	taskid_t id = 0;
	do {
		id = task->_nextTask++;
	} while (id == k_task_parent_id || _tf_task_get_stub(task, id));

	task_child_node_t* node = malloc(sizeof(task_child_node_t));
	*node = (task_child_node_t) {
		.id = id,
		.stub = stub,
		.next = task->_children,
	};
	task->_children = node;
	task->_child_count++;
	_tf_task_trace_children(task);
	return id;
}

void tf_task_remove_child(tf_task_t* task, tf_taskstub_t* child)
{
	_import_record_release_for_task(task, tf_taskstub_get_id(child));
	_export_record_release_for_task(task, tf_taskstub_get_id(child));
	for (task_child_node_t** it = &task->_children;
		*it;
		it = &(*it)->next) {
		if ((*it)->stub == child) {
			task_child_node_t* node = *it;
			*it = node->next;
			free(node);
			task->_child_count--;
			_tf_task_trace_children(task);
			break;
		}
	}
}

static void _import_finalizer(JSRuntime* runtime, JSValue value)
{
	import_record_t* import = JS_GetOpaque(value, _import_class_id);
	_import_record_release(import);
}

static void _import_mark_func(JSRuntime* runtime, JSValueConst value, JS_MarkFunc mark_func)
{
	import_record_t* import = JS_GetOpaque(value, _import_class_id);
	if (import && import->_useCount > 0) {
		JS_MarkValue(runtime, import->_function, mark_func);
	}
}

static void _tf_task_promise_rejection_tracker(JSContext* context, JSValueConst promise, JSValueConst reason, JS_BOOL is_handled, void* user_data)
{
	tf_task_t* task = user_data;
	if (!is_handled) {
		tf_task_report_error(task, reason);
	}
}

tf_task_t* tf_task_create() {
	tf_task_t* task = malloc(sizeof(tf_task_t));
	*task = (tf_task_t) { 0 };
	task->_loop = uv_loop_new();
	++_count;
	task->_runtime = JS_NewRuntime();
	task->_context = JS_NewContext(task->_runtime);
	JS_SetContextOpaque(task->_context, task);

	JS_SetHostPromiseRejectionTracker(task->_runtime, _tf_task_promise_rejection_tracker, task);

	JS_NewClassID(&_import_class_id);
	JSClassDef def = {
		.class_name = "imported_function",
		.finalizer = _import_finalizer,
		.gc_mark = _import_mark_func,
		.call = _import_call,
	};
	JS_NewClass(task->_runtime, _import_class_id, &def);
	task->_loadedFiles = JS_NewObject(task->_context);
	return task;
}

void tf_task_configure_from_stdin(tf_task_t* task) {
	task->_parent = tf_taskstub_create_parent(task, STDIN_FILENO);
}

void tf_task_activate(tf_task_t* task)
{
	JSContext* context = task->_context;
	JSValue global = JS_GetGlobalObject(context);
	JS_SetPropertyStr(context, global, "exports", JS_NewObject(context));

	JSAtom atom = JS_NewAtom(context, "parent");
	JS_DefinePropertyGetSet(context, global, atom, JS_NewCFunction(context, _tf_task_get_parent, "parent", 0), JS_UNDEFINED, 0);
	JS_FreeAtom(context, atom);

	JSValue tildefriends = JS_NewObject(context);
	JS_SetPropertyStr(context, tildefriends, "ssb_port", JS_NewInt32(context, task->_ssb_port));
	JS_SetPropertyStr(context, tildefriends, "http_port", JS_NewInt32(context, task->_http_port));
	JS_SetPropertyStr(context, tildefriends, "https_port", JS_NewInt32(context, task->_https_port));
	JS_SetPropertyStr(context, global, "tildefriends", tildefriends);

	if (task->_trusted) {
		sqlite3_open(task->_db_path ? task->_db_path : "db.sqlite", &task->_db);

		JS_SetPropertyStr(context, global, "require", JS_NewCFunction(context, _tf_task_require, "require", 1));
		JS_SetPropertyStr(context, global, "Task", tf_taskstub_init(context));
		JS_SetPropertyStr(context, global, "Socket", tf_socket_init(context));
		JS_SetPropertyStr(context, global, "TlsContext", tf_tls_context_wrapper_init(context));
		tf_database_init(context, task->_db);
		tf_file_init(context);

		task->_trace = tf_trace_create();

		task->_ssb = tf_ssb_create(task->_loop, task->_context, task->_db, task->_secrets_path);
		tf_ssb_set_trace(task->_ssb, task->_trace);
		tf_ssb_broadcast_listener_start(task->_ssb, false);
		tf_ssb_init(context, task->_ssb);
		if (task->_ssb_port) {
			tf_ssb_server_open(task->_ssb, task->_ssb_port);
		}

		JS_SetPropertyStr(context, global, "trace", JS_NewCFunction(context, _tf_task_trace, "trace", 1));
	} else {
		JS_SetPropertyStr(context, global, "require", JS_NewCFunction(context, _tf_task_sandbox_require, "sandboxRequire", 0));
	}

	tf_bcrypt_init(context);
	JS_SetPropertyStr(context, global, "utf8Decode", JS_NewCFunction(context, _tf_task_utf8Decode, "utf8Decode", 1));
	JS_SetPropertyStr(context, global, "print", JS_NewCFunction(context, _tf_task_print, "print", 0));
	JS_SetPropertyStr(context, global, "exit", JS_NewCFunction(context, _tf_task_exit, "exit", 1));
	JS_SetPropertyStr(context, global, "version", JS_NewCFunction(context, _tf_task_version, "version", 0));
	JS_SetPropertyStr(context, global, "setTimeout", JS_NewCFunction(context, _task_setTimeout, "setTimeout", 2));
	JS_SetPropertyStr(context, global, "getFile", JS_NewCFunction(context, _tf_task_getFile, "getFile", 1));
	JS_FreeValue(context, global);
}

void tf_task_run(tf_task_t* task) {
	uv_run(task->_loop, UV_RUN_DEFAULT);
}

void tf_task_set_trusted(tf_task_t* task, bool trusted) {
	task->_trusted = trusted;
}

JSContext* tf_task_get_context(tf_task_t* task) {
	return task->_context;
}

void tf_task_destroy(tf_task_t* task) {
	import_record_t* it = task->_imports;
	while (it) {
		import_record_t* next = it->_next;
		JS_FreeValue(task->_context, it->_function);
		free(it);
		it = next;
	}
	task->_imports = NULL;

	while (task->_exports) {
		export_record_t* export = task->_exports;
		JS_FreeValue(task->_context, export->_function);
		task->_exports = export->_next;
		free(export);
	}
	while (task->_children) {
		task_child_node_t* node = task->_children;
		tf_taskstub_destroy(node->stub);
		task->_children = node->next;
		free(node);
	}
	if (task->_parent) {
		JS_FreeValue(task->_context, tf_taskstub_get_task_object(task->_parent));
	}
	while (task->_promises) {
		tf_task_reject_promise(task, task->_promises->id, JS_NULL);
	}
	JS_FreeValue(task->_context, task->_requires);
	JS_FreeValue(task->_context, task->_loadedFiles);
	while (task->_scriptExports) {
		script_export_t* export = task->_scriptExports;
		JS_FreeValue(task->_context, export->value);
		task->_scriptExports = export->next;
		free((void*)export->name);
		free(export);
	}

	if (task->_trace) {
		tf_trace_destroy(task->_trace);
	}

	if (task->_ssb) {
		tf_ssb_destroy(task->_ssb);
	}
	JS_FreeContext(task->_context);
	JS_FreeRuntime(task->_runtime);

	if (task->_db) {
		sqlite3_close(task->_db);
	}

	uv_print_all_handles(task->_loop, stdout);
	uv_loop_delete(task->_loop);
	--_count;
	free((void*)task->_path);
	free(task);
}

JSValue tf_task_add_import(tf_task_t* task, taskid_t stub_id, exportid_t export_id)
{
	JSValue function = JS_NewObjectClass(task->_context, _import_class_id);
	import_record_t* import = malloc(sizeof(import_record_t));
	JS_SetOpaque(function, import);
	*import = (import_record_t) {
		._function = JS_DupValue(task->_context, function),
		._export = export_id,
		._owner = task,
		._task = stub_id,
		._useCount = 1,
		._next = task->_imports,
	};

	task->_imports = import;
	task->_import_count++;
	_tf_task_trace_imports(task);
	return function;
}

tf_task_t* tf_task_get(JSContext* context) {
	return JS_GetContextOpaque(context);
}

void tf_task_run_jobs(tf_task_t* task) {
	while (JS_IsJobPending(task->_runtime)) {
		JSContext* context = NULL;
		int r = JS_ExecutePendingJob(task->_runtime, &context);
		JSValue result = JS_GetException(context);
		tf_task_report_error(task, result);
		if (r < 0) {
			js_std_dump_error(context);
		} else if (r == 0) {
			break;
		}
	}
}

void tf_task_send_promise_message(tf_task_t* from, tf_taskstub_t* to, tf_task_message_t type, promiseid_t promise, JSValue payload)
{
	_tf_task_sendPromiseMessage(from, to, type, promise, payload);
}

JSValue tf_try_get_typed_array_buffer(JSContext *ctx, JSValueConst obj, size_t *pbyte_offset, size_t *pbyte_length, size_t *pbytes_per_element)
{
	JSValue result = JS_GetTypedArrayBuffer(ctx, obj, pbyte_offset, pbyte_length, pbytes_per_element);
	JS_FreeValue(ctx, JS_GetException(ctx));
	return result;
}

uint8_t *tf_try_get_array_buffer(JSContext *ctx, size_t *psize, JSValueConst obj)
{
	uint8_t* result = JS_GetArrayBuffer(ctx, psize, obj);
	JS_FreeValue(ctx, JS_GetException(ctx));
	return result;
}

void tf_task_set_ssb_port(tf_task_t* task, int port)
{
	task->_ssb_port = port;
}

void tf_task_set_http_port(tf_task_t* task, int port)
{
	task->_http_port = port;
}

void tf_task_set_https_port(tf_task_t* task, int port)
{
	task->_https_port = port;
}

void tf_task_set_db_path(tf_task_t* task, const char* db_path)
{
	task->_db_path = db_path;
}

void tf_task_set_secrets_path(tf_task_t* task, const char* secrets_path)
{
	task->_secrets_path = secrets_path;
}