ProjectExplorer: Rework the build step run interface

Originally, the build manager used to run all build steps in a dedicated
thread. Communication between the step and the manager happened via a
QFutureInterface that was passed into the step's run() function.
Later, new steps were added that operated asynchronously, so the build
manager had to differentiate between the different kinds of steps for
starting and stopping.
These days, almost all build and deploy steps work asynchronously, which
made the QFuture-based interface look increasingly odd.
With this patch, all build steps are expected to work asynchronously, so
the build manager no longer needs to differentiate. Steps are started
and requested to stop via the run() and cancel() functions,
respectively, and emit the finished() signal when they are done. Build
step implementors no longer have to deal with a QFutureInterface. For
steps whose implementation is inherently synchronous, the BuildStep base
class offers a runInThread() function.

Change-Id: If905c68b234c5a669f6e19f43142eaa57d594803
Reviewed-by: hjk <hjk@qt.io>

2 files changed, 14 insertions, 7 deletions

diff --git a/src/plugins/nim/project/nimcompilercleanstep.cpp b/src/plugins/nim/project/nimcompilercleanstep.cpp
index 85df3084452..f07f5011062 100644
--- a/src/plugins/nim/project/nimcompilercleanstep.cpp
+++ b/src/plugins/nim/project/nimcompilercleanstep.cpp
@@ -61,28 +61,33 @@ bool NimCompilerCleanStep::init()
     return result;
 }
 
-void NimCompilerCleanStep::run(QFutureInterface<bool> &fi)
+void NimCompilerCleanStep::doRun()
 {
     if (!m_buildDir.exists()) {
         emit addOutput(tr("Build directory \"%1\" does not exist.").arg(m_buildDir.toUserOutput()), BuildStep::OutputFormat::ErrorMessage);
-        reportRunResult(fi, false);
+        emit finished(false);
         return;
     }
 
     if (!removeCacheDirectory()) {
         emit addOutput(tr("Failed to delete the cache directory."), BuildStep::OutputFormat::ErrorMessage);
-        reportRunResult(fi, false);
+        emit finished(false);
         return;
     }
 
     if (!removeOutFilePath()) {
         emit addOutput(tr("Failed to delete the out file."), BuildStep::OutputFormat::ErrorMessage);
-        reportRunResult(fi, false);
+        emit finished(false);
         return;
     }
 
     emit addOutput(tr("Clean step completed successfully."), BuildStep::OutputFormat::NormalMessage);
-    reportRunResult(fi, true);
+    emit finished(true);
+}
+
+void NimCompilerCleanStep::doCancel()
+{
+    // Can be left empty. The run() function hardly does anything.
 }
 
 bool NimCompilerCleanStep::removeCacheDirectory()
diff --git a/src/plugins/nim/project/nimcompilercleanstep.h b/src/plugins/nim/project/nimcompilercleanstep.h
index 1e062591bd1..e250d88f452 100644
--- a/src/plugins/nim/project/nimcompilercleanstep.h
+++ b/src/plugins/nim/project/nimcompilercleanstep.h
@@ -39,10 +39,12 @@ public:
     NimCompilerCleanStep(ProjectExplorer::BuildStepList *parentList);
 
     ProjectExplorer::BuildStepConfigWidget *createConfigWidget() override;
-    bool init() override;
-    void run(QFutureInterface<bool> &fi) override;
 
 private:
+    bool init() override;
+    void doRun() override;
+    void doCancel() override;
+
     bool removeCacheDirectory();
     bool removeOutFilePath();