From cd70d10dce8993d9923619aa4582b5c84a46b12e Mon Sep 17 00:00:00 2001
From: Jarek Kobus <jaroslaw.kobus@qt.io>
Date: Thu, 1 Jun 2023 13:02:25 +0200
Subject: [PATCH] SilverSearcher: Don't crash on giant output from ag

Make cancel and continue button working. Make pausing
above 200000 hits working.

Fixes: QTCREATORBUG-29130
Change-Id: I55429ae1b4d80dacfcd7e8366133657d0c44a0d6
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
---
 .../findinfilessilversearcher.cpp             | 45 +++++++++++++++++--
 1 file changed, 41 insertions(+), 4 deletions(-)

diff --git a/src/plugins/silversearcher/findinfilessilversearcher.cpp b/src/plugins/silversearcher/findinfilessilversearcher.cpp
index b7e26d071b1..7d9e5f1e141 100644
--- a/src/plugins/silversearcher/findinfilessilversearcher.cpp
+++ b/src/plugins/silversearcher/findinfilessilversearcher.cpp
@@ -114,10 +114,31 @@ static void runSilverSeacher(QPromise<SearchResultItems> &promise,
     process.setCommand({"ag", arguments});
     ParserState parserState;
     const std::optional<QRegularExpression> regExp = regExpFromParameters(parameters);
-    process.setStdOutCallback([&promise, &parserState, regExp](const QString &output) {
-        SilverSearcher::parse(promise, output, &parserState, regExp);
+    QStringList outputBuffer;
+    // The states transition exactly in this order:
+    enum State { BelowLimit, AboveLimit, Paused, Resumed };
+    State state = BelowLimit;
+    process.setStdOutCallback([&process, &loop, &promise, &state, &outputBuffer, &parserState,
+                               regExp](const QString &output) {
+        if (promise.isCanceled()) {
+            process.close();
+            loop.quit();
+            return;
+        }
+        // The SearchResultWidget is going to pause the search anyway, so start buffering
+        // the output.
+        if (state == AboveLimit || state == Paused) {
+            outputBuffer.append(output);
+        } else {
+            SilverSearcher::parse(promise, output, &parserState, regExp);
+            if (state == BelowLimit && parserState.m_reportedResultsCount > 200000)
+                state = AboveLimit;
+        }
+    });
+    QObject::connect(&process, &Process::done, &loop, [&loop, &promise, &state] {
+        if (state == BelowLimit || state == Resumed || promise.isCanceled())
+            loop.quit();
     });
-    QObject::connect(&process, &Process::done, &loop, &QEventLoop::quit);
 
     process.start();
     if (process.state() == QProcess::NotRunning)
@@ -125,7 +146,23 @@ static void runSilverSeacher(QPromise<SearchResultItems> &promise,
 
     QFutureWatcher<void> watcher;
     QFuture<void> future(promise.future());
-    QObject::connect(&watcher, &QFutureWatcherBase::canceled, &loop, &QEventLoop::quit);
+    QObject::connect(&watcher, &QFutureWatcherBase::canceled, &loop, [&process, &loop] {
+        process.close();
+        loop.quit();
+    });
+    QObject::connect(&watcher, &QFutureWatcherBase::paused, &loop, [&state] { state = Paused; });
+    QObject::connect(&watcher, &QFutureWatcherBase::resumed, &loop,
+                     [&process, &loop, &promise, &state, &outputBuffer, &parserState, regExp] {
+        state = Resumed;
+        for (const QString &output : outputBuffer) {
+            if (promise.isCanceled()) {
+                process.close();
+                loop.quit();
+            }
+            SilverSearcher::parse(promise, output, &parserState, regExp);
+        }
+        outputBuffer.clear();
+    });
     watcher.setFuture(future);
     loop.exec(QEventLoop::ExcludeUserInputEvents);
 }