Make the promises js-less using a newly introduced thunk pool

Since we cannot rely on the clients specifying a suitable CSP that will
not forbid execution of js injections, we have to refrain from using
any explicit <script> elements. To keep the promise system working, a
thunk pool was introduced which keeps track of a limited pool of promise
callback exports. In case the resources are busy, pending calls are
enqueued. This works since the JS Promise.then/catch/finally always fire,
even on ready/failed promises.
As the situation of full thunk pool allocation is unlikely to happen
en masse IRL, the solution should not adversely affect the performance.
Heavy unit tests were created to confirm the solution works as expected.

Task-number: QTBUG-99611
Change-Id: I0e6982d4ee76a4263b59e72b004b3ff2f167e4df
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

1 files changed, 71 insertions, 110 deletions

diff --git a/tests/manual/wasm/qstdweb/promise_main.cpp b/tests/manual/wasm/qstdweb/promise_main.cpp
index 456fb7eb32..351f06c91d 100644
--- a/tests/manual/wasm/qstdweb/promise_main.cpp
+++ b/tests/manual/wasm/qstdweb/promise_main.cpp
@@ -17,14 +17,15 @@ class WasmPromiseTest : public QObject
     Q_OBJECT
 
 public:
-    WasmPromiseTest() : m_window(val::global("window")), m_testSupport(val::object()) {
-        m_window.set("testSupport", m_testSupport);
-    }
+    WasmPromiseTest() : m_window(val::global("window")), m_testSupport(val::object()) {}
 
-    ~WasmPromiseTest() noexcept {}
+    ~WasmPromiseTest() noexcept = default;
 
 private:
     void init() {
+        m_testSupport = val::object();
+        m_window.set("testSupport", m_testSupport);
+
         EM_ASM({
             testSupport.resolve = {};
             testSupport.reject = {};
@@ -108,52 +109,32 @@ void WasmPromiseTest::multipleResolve()
 {
     init();
 
-    auto onThen = std::make_shared<BarrierCallback>(3, []() {
+    static constexpr int promiseCount = 1000;
+
+    auto onThen = std::make_shared<BarrierCallback>(promiseCount, []() {
         QWASMSUCCESS();
     });
 
-    qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
-        .thenFunc = [=](val result) {
-            QWASMVERIFY(result.isString());
-            QWASMCOMPARE("Data 1", result.as<std::string>());
-
-            (*onThen)();
-        },
-        .catchFunc = [](val error) {
-            Q_UNUSED(error);
-            QWASMFAIL("Unexpected catch");
-        }
-    }, std::string("1"));
-    qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
-        .thenFunc = [=](val result) {
-            QWASMVERIFY(result.isString());
-            QWASMCOMPARE("Data 2", result.as<std::string>());
-
-            (*onThen)();
-        },
-        .catchFunc = [](val error) {
-            Q_UNUSED(error);
-            QWASMFAIL("Unexpected catch");
-        }
-    }, std::string("2"));
-    qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
-        .thenFunc = [=](val result) {
-            QWASMVERIFY(result.isString());
-            QWASMCOMPARE("Data 3", result.as<std::string>());
-
-            (*onThen)();
-        },
-        .catchFunc = [](val error) {
-            Q_UNUSED(error);
-            QWASMFAIL("Unexpected catch");
-        }
-    }, std::string("3"));
+    for (int i = 0; i < promiseCount; ++i) {
+        qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
+            .thenFunc = [=](val result) {
+                QWASMVERIFY(result.isString());
+                QWASMCOMPARE(QString::number(i).toStdString(), result.as<std::string>());
+
+                (*onThen)();
+            },
+            .catchFunc = [](val error) {
+                Q_UNUSED(error);
+                QWASMFAIL("Unexpected catch");
+            }
+        }, (QStringLiteral("test") + QString::number(i)).toStdString());
+    }
 
     EM_ASM({
-        testSupport.resolve["3"]("Data 3");
-        testSupport.resolve["1"]("Data 1");
-        testSupport.resolve["2"]("Data 2");
-    });
+        for (let i = $0 - 1; i >= 0; --i) {
+            testSupport.resolve['test' + i](`${i}`);
+        }
+    }, promiseCount);
 }
 
 void WasmPromiseTest::simpleReject()
@@ -179,53 +160,32 @@ void WasmPromiseTest::simpleReject()
 
 void WasmPromiseTest::multipleReject()
 {
-    init();
-    auto onThen = std::make_shared<BarrierCallback>(3, []() {
+    static constexpr int promiseCount = 1000;
+
+    auto onCatch = std::make_shared<BarrierCallback>(promiseCount, []() {
         QWASMSUCCESS();
     });
 
-    qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
-        .thenFunc = [](val result) {
-            Q_UNUSED(result);
-            QWASMFAIL("Unexpected then");
-        },
-        .catchFunc = [=](val error) {
-            QWASMVERIFY(error.isString());
-            QWASMCOMPARE("Error 1", error.as<std::string>());
-
-            (*onThen)();
-        }
-    }, std::string("1"));
-    qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
-        .thenFunc = [](val result) {
-            Q_UNUSED(result);
-            QWASMFAIL("Unexpected then");
-        },
-        .catchFunc = [=](val error) {
-            QWASMVERIFY(error.isString());
-            QWASMCOMPARE("Error 2", error.as<std::string>());
-
-            (*onThen)();
-        }
-    }, std::string("2"));
-    qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
-        .thenFunc = [](val result) {
-            Q_UNUSED(result);
-            QWASMFAIL("Unexpected then");
-        },
-        .catchFunc = [=](val error) {
-            QWASMVERIFY(error.isString());
-            QWASMCOMPARE("Error 3", error.as<std::string>());
-
-            (*onThen)();
-        }
-    }, std::string("3"));
+    for (int i = 0; i < promiseCount; ++i) {
+        qstdweb::Promise::make(m_testSupport, "makeTestPromise", {
+            .thenFunc = [=](val result) {
+                QWASMVERIFY(result.isString());
+                QWASMCOMPARE(QString::number(i).toStdString(), result.as<std::string>());
+
+                (*onCatch)();
+            },
+            .catchFunc = [](val error) {
+                Q_UNUSED(error);
+                QWASMFAIL("Unexpected catch");
+            }
+        }, (QStringLiteral("test") + QString::number(i)).toStdString());
+    }
 
     EM_ASM({
-        testSupport.reject["3"]("Error 3");
-        testSupport.reject["1"]("Error 1");
-        testSupport.reject["2"]("Error 2");
-    });
+        for (let i = $0 - 1; i >= 0; --i) {
+            testSupport.resolve['test' + i](`${i}`);
+        }
+    }, promiseCount);
 }
 
 void WasmPromiseTest::throwInThen()
@@ -241,8 +201,7 @@ void WasmPromiseTest::throwInThen()
         },
         .catchFunc = [](val error) {
             QWASMCOMPARE("Expected error", error.as<std::string>());
-            //QWASMSUCCESS();
-            QWASMFAIL("Other nasty problem");
+            QWASMSUCCESS();
         }
     }, std::string("throwInThen"));
 
@@ -386,39 +345,42 @@ void WasmPromiseTest::all()
 {
     init();
 
-    val promise1 = m_testSupport.call<val>("makeTestPromise", val("promise1"));
-    val promise2 = m_testSupport.call<val>("makeTestPromise", val("promise2"));
-    val promise3 = m_testSupport.call<val>("makeTestPromise", val("promise3"));
-
+    static constexpr int promiseCount = 1000;
     auto thenCalledOnce = std::shared_ptr<bool>();
     *thenCalledOnce = true;
 
-    qstdweb::Promise::all({promise1, promise2, promise3}, {
-        .thenFunc = [thenCalledOnce](val result) {
+    std::vector<val> promises;
+    promises.reserve(promiseCount);
+
+    for (int i = 0; i < promiseCount; ++i) {
+        promises.push_back(m_testSupport.call<val>("makeTestPromise", val(("all" + QString::number(i)).toStdString())));
+    }
+
+    qstdweb::Promise::all(std::move(promises), {
+        .thenFunc = [=](val result) {
             QWASMVERIFY(*thenCalledOnce);
             *thenCalledOnce = false;
 
             QWASMVERIFY(result.isArray());
-            QWASMCOMPARE(3, result["length"].as<int>());
-            QWASMCOMPARE("Data 1", result[0].as<std::string>());
-            QWASMCOMPARE("Data 2", result[1].as<std::string>());
-            QWASMCOMPARE("Data 3", result[2].as<std::string>());
+            QWASMCOMPARE(promiseCount, result["length"].as<int>());
+            for (int i = 0; i < promiseCount; ++i) {
+                QWASMCOMPARE(QStringLiteral("Data %1").arg(i).toStdString(), result[i].as<std::string>());
+            }
 
             QWASMSUCCESS();
         },
-        .catchFunc = [](val result) {
-            Q_UNUSED(result);
-            EM_ASM({
-                throw new Error("Unexpected error");
-            });
+        .catchFunc = [](val error) {
+            Q_UNUSED(error);
+            QWASMFAIL("Unexpected catch");
         }
     });
 
     EM_ASM({
-        testSupport.resolve["promise3"]("Data 3");
-        testSupport.resolve["promise1"]("Data 1");
-        testSupport.resolve["promise2"]("Data 2");
-    });
+        console.log('Resolving');
+        for (let i = $0 - 1; i >= 0; --i) {
+            testSupport.resolve['all' + i](`Data ${i}`);
+        }
+    }, promiseCount);
 }
 
 void WasmPromiseTest::allWithThrow()
@@ -503,8 +465,7 @@ void WasmPromiseTest::allWithFinallyAndThrow()
         .finallyFunc = [finallyCalledOnce]() {
             QWASMVERIFY(*finallyCalledOnce);
             *finallyCalledOnce = false;
-            // QWASMSUCCESS();
-            QWASMFAIL("Some nasty problem");
+            QWASMSUCCESS();
         }
     });