SilverSearcher: Make the search cancellable

Especially when there are lot of files, and not too much results.

Change-Id: Id9e89c5d0d681e11dd8a9fb5c2373164dbeef3fd
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

3 files changed, 76 insertions, 26 deletions

diff --git a/src/plugins/silversearcher/findinfilessilversearcher.cpp b/src/plugins/silversearcher/findinfilessilversearcher.cpp
index 43397a03f6d..b7e26d071b1 100644
--- a/src/plugins/silversearcher/findinfilessilversearcher.cpp
+++ b/src/plugins/silversearcher/findinfilessilversearcher.cpp
@@ -16,6 +16,7 @@
 #include <QSettings>
 
 using namespace Core;
+using namespace SilverSearcher;
 using namespace TextEditor;
 using namespace Utils;
 
@@ -58,6 +59,21 @@ static bool isSilverSearcherAvailable()
         && silverSearcherProcess.cleanedStdOut().contains("ag version");
 }
 
+static std::optional<QRegularExpression> regExpFromParameters(const FileFindParameters &parameters)
+{
+    if (!(parameters.flags & FindRegularExpression))
+        return {};
+
+    const QRegularExpression::PatternOptions patternOptions
+        = (parameters.flags & FindCaseSensitively)
+              ? QRegularExpression::NoPatternOption
+              : QRegularExpression::CaseInsensitiveOption;
+    QRegularExpression regExp;
+    regExp.setPattern(parameters.text);
+    regExp.setPatternOptions(patternOptions);
+    return regExp;
+}
+
 static void runSilverSeacher(QPromise<SearchResultItems> &promise,
                              const FileFindParameters &parameters)
 {
@@ -92,26 +108,26 @@ static void runSilverSeacher(QPromise<SearchResultItems> &promise,
 
     arguments << "--" << parameters.text << directory.normalizedPathName().toString();
 
+    QEventLoop loop;
+
     Process process;
     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);
+    });
+    QObject::connect(&process, &Process::done, &loop, &QEventLoop::quit);
+
     process.start();
-    if (process.waitForFinished()) {
-        std::optional<QRegularExpression> regExp;
-        if (parameters.flags & FindRegularExpression) {
-            regExp = QRegularExpression();
-            const QRegularExpression::PatternOptions patternOptions
-                = (parameters.flags & FindCaseSensitively)
-                      ? QRegularExpression::NoPatternOption
-                      : QRegularExpression::CaseInsensitiveOption;
-            regExp->setPattern(parameters.text);
-            regExp->setPatternOptions(patternOptions);
-        }
-        const SearchResultItems items = SilverSearcher::parse(process.cleanedStdOut(), regExp);
-        if (!items.isEmpty())
-            promise.addResult(items);
-    } else {
-        promise.future().cancel();
-    }
+    if (process.state() == QProcess::NotRunning)
+        return;
+
+    QFutureWatcher<void> watcher;
+    QFuture<void> future(promise.future());
+    QObject::connect(&watcher, &QFutureWatcherBase::canceled, &loop, &QEventLoop::quit);
+    watcher.setFuture(future);
+    loop.exec(QEventLoop::ExcludeUserInputEvents);
 }
 
 } // namespace
diff --git a/src/plugins/silversearcher/silversearcherparser.cpp b/src/plugins/silversearcher/silversearcherparser.cpp
index be4e9096c4c..9cdf5211a67 100644
--- a/src/plugins/silversearcher/silversearcherparser.cpp
+++ b/src/plugins/silversearcher/silversearcherparser.cpp
@@ -3,6 +3,8 @@
 
 #include "silversearcherparser.h"
 
+#include <QFuture>
+
 using namespace Utils;
 
 namespace SilverSearcher {
@@ -94,23 +96,28 @@ static bool parseLineHits(QStringView *remainingInput, QList<QPair<int, int>> *h
     return true;
 }
 
-SearchResultItems parse(const QString &input, const std::optional<QRegularExpression> &regExp)
+void parse(QPromise<SearchResultItems> &promise, const QString &input,
+           ParserState *parserState, const std::optional<QRegularExpression> &regExp)
 {
+    QTC_ASSERT(parserState, return);
     SearchResultItems items;
 
     QStringView remainingInput(input);
     while (true) {
+        if (promise.isCanceled())
+            return;
+
         if (remainingInput.isEmpty())
             break;
 
         const QStringView filePathLine = nextLine(&remainingInput);
-        if (filePathLine.isEmpty())
-            continue;
-
-        if (!filePathLine.startsWith(':'))
+        if (filePathLine.isEmpty()) {
+            parserState->m_lastFilePath = {}; // Clear the parser state
             continue;
+        }
 
-        const FilePath filePath = FilePath::fromPathPart(filePathLine.mid(1));
+        if (filePathLine.startsWith(':'))
+            parserState->m_lastFilePath = FilePath::fromPathPart(filePathLine.mid(1));
 
         while (true) {
             QStringView hitLine = nextLine(&remainingInput);
@@ -126,7 +133,7 @@ SearchResultItems parse(const QString &input, const std::optional<QRegularExpres
                 break;
 
             SearchResultItem item;
-            item.setFilePath(filePath);
+            item.setFilePath(parserState->m_lastFilePath);
             item.setDisplayText(hitLine.toString());
             item.setUseTextEditorFont(true);
             for (const QPair<int, int> &hit : hits) {
@@ -138,7 +145,20 @@ SearchResultItems parse(const QString &input, const std::optional<QRegularExpres
             }
         }
     }
-    return items;
+    if (!items.isEmpty())
+        promise.addResult(items);
+
+    parserState->m_reportedResultsCount += items.count();
+}
+
+SearchResultItems parse(const QString &input, const std::optional<QRegularExpression> &regExp)
+{
+    QPromise<SearchResultItems> promise;
+    promise.start();
+    ParserState dummy;
+    SilverSearcher::parse(promise, input, &dummy, regExp);
+    promise.finish();
+    return promise.future().resultCount() ? promise.future().result() : SearchResultItems();
 }
 
 } // namespace SilverSearcher
diff --git a/src/plugins/silversearcher/silversearcherparser.h b/src/plugins/silversearcher/silversearcherparser.h
index f9d8502759a..1cc5ccb773c 100644
--- a/src/plugins/silversearcher/silversearcherparser.h
+++ b/src/plugins/silversearcher/silversearcherparser.h
@@ -5,11 +5,25 @@
 
 #include <utils/searchresultitem.h>
 
+#include <QPromise>
 #include <QRegularExpression>
 
+namespace Utils { class FilePath; }
+
 namespace SilverSearcher {
 
-Utils::SearchResultItems parse(const QString &output,
+class ParserState
+{
+public:
+    Utils::FilePath m_lastFilePath;
+    int m_reportedResultsCount = 0;
+};
+
+void parse(QPromise<Utils::SearchResultItems> &promise, const QString &input,
+           ParserState *parserState = nullptr,
+           const std::optional<QRegularExpression> &regExp = {});
+
+Utils::SearchResultItems parse(const QString &input,
                                const std::optional<QRegularExpression> &regExp = {});
 
 } // namespace SilverSearcher