AutotoolsPM: Make MakefileParser cancelable

Change-Id: Iccd3c54c401433b82f567cfef281a0043af2efff
Reviewed-by: hjk <hjk@qt.io>

src/plugins/autotoolsprojectmanager/autotoolsbuildsystem.cpp

@@ -34,7 +34,7 @@ AutotoolsBuildSystem::~AutotoolsBuildSystem() = default;
 static void parseMakefile(QPromise<MakefileParserOutputData> &promise, const QString &makefile)
 {
     MakefileParser parser(makefile);
-    if (parser.parse())
+    if (parser.parse(QFuture<void>(promise.future())))
         promise.addResult(parser.outputData());
     else
         promise.future().cancel();

src/plugins/autotoolsprojectmanager/makefileparser.cpp

@@ -28,8 +28,14 @@ MakefileParser::~MakefileParser()
 
 bool MakefileParser::parse()
 {
-    m_cancel = false;
+    QFutureInterface<void> fi;
+    fi.reportStarted(); // The default constructed future is canceled otherwise.
+    return parse(fi.future());
+}
 
+bool MakefileParser::parse(const QFuture<void> &future)
+{
+    m_future = future;
     m_success = true;
     m_outputData.m_executable.clear();
     m_outputData.m_sources.clear();
@@ -70,16 +76,6 @@ bool MakefileParser::parse()
     return m_success;
 }
 
-void MakefileParser::cancel()
-{
-    m_cancel = true;
-}
-
-bool MakefileParser::isCanceled() const
-{
-    return m_cancel;
-}
-
 MakefileParser::TopTarget MakefileParser::topTarget() const
 {
     const QString line = m_line.simplified();
@@ -164,7 +160,7 @@ void MakefileParser::parseDefaultSourceExtensions()
 void MakefileParser::parseSubDirs()
 {
     QTC_ASSERT(m_line.contains(QLatin1String("SUBDIRS")), return);
-    if (isCanceled()) {
+    if (m_future.isCanceled()) {
         m_success = false;
         return;
     }
@@ -222,7 +218,7 @@ void MakefileParser::parseSubDirs()
 
         MakefileParser parser(subDirMakefile);
         connect(&parser, &MakefileParser::status, this, &MakefileParser::status);
-        const bool success = parser.parse();
+        const bool success = parser.parse(m_future);
 
         // Don't return, try to parse as many sub directories
         // as possible
@@ -262,7 +258,7 @@ void MakefileParser::parseSubDirs()
 QStringList MakefileParser::directorySources(const QString &directory,
                                              const QStringList &extensions)
 {
-    if (isCanceled()) {
+    if (m_future.isCanceled()) {
         m_success = false;
         return {};
     }

src/plugins/autotoolsprojectmanager/makefileparser.h

@@ -5,12 +5,10 @@
 
 #include <projectexplorer/projectmacro.h>
 
+#include <QFuture>
+#include <QObject>
 #include <QStringList>
 #include <QTextStream>
-#include <QObject>
-#include <QVector>
-
-#include <atomic>
 
 QT_BEGIN_NAMESPACE
 class QDir;
@@ -71,22 +69,10 @@ public:
      *         the makefile could not be opened.
      */
     bool parse();
+    bool parse(const QFuture<void> &future);
 
     MakefileParserOutputData outputData() const { return m_outputData; }
 
-    /**
-     * Cancels the parsing. Calling this function only makes sense, if the
-     * parser runs in a different thread than the caller of this function.
-     * The function is thread-safe.
-     */
-    void cancel();
-
-    /**
-     * @return True, if the parser has been cancelled by MakefileParser::cancel().
-     *         The function is thread-safe.
-     */
-    bool isCanceled() const;
-
 signals:
     /**
      * Is emitted periodically during parsing the Makefile.am files
@@ -224,7 +210,7 @@ private:
     bool m_success = false;     ///< Return value for MakefileParser::parse().
     bool m_subDirsEmpty = false;///< States if last subdirs var was empty
 
-    std::atomic_bool m_cancel = false;      ///< True, if the parsing should be cancelled.
+    QFuture<void> m_future;     ///< For periodic checking of cancelled state.
 
     QString m_makefile;         ///< Filename of the makefile
     MakefileParserOutputData m_outputData;