Improve API for QgsRuntimeProfiler

Make it easier to nest profiled calls by removing the concept of groups,
and instead allow any profiled operation to have log child operation
runtimes as well as its overall runtime.

python/core/auto_generated/qgsruntimeprofiler.sip.in

@@ -21,17 +21,30 @@ class QgsRuntimeProfiler
 Constructor to create a new runtime profiler.
 %End
 
-    void beginGroup( const QString &name );
+ void beginGroup( const QString &name ) /Deprecated/;
 %Docstring
 Begin the group for the profiler. Groups will append {GroupName}/ to the
 front of the profile tag set using start.
 
 :param name: The name of the group.
+
+.. deprecated::
+   use start() instead
 %End
 
-    void endGroup();
+ void endGroup() /Deprecated/;
 %Docstring
 End the current active group.
+
+.. deprecated::
+   use end() instead
+%End
+
+    QStringList childGroups( const QString &parent = QString() ) const;
+%Docstring
+Returns a list of all child groups with the specified ``parent``.
+
+.. versionadded:: 3.14
 %End
 
     void start( const QString &name );
@@ -47,6 +60,12 @@ Start a profile event with the given name.
 End the current profile event.
 %End
 
+    double profileTime( const QString &name ) const;
+%Docstring
+Returns the profile time for the specified ``name``.
+
+.. versionadded:: 3.14
+%End
 
     void clear();
 %Docstring

src/core/qgsruntimeprofiler.cpp

@@ -14,46 +14,80 @@
  ***************************************************************************/
 #include "qgsruntimeprofiler.h"
 #include "qgslogger.h"
+#include "qgis.h"
+#include "qgsapplication.h"
+#include <QSet>
 
 void QgsRuntimeProfiler::beginGroup( const QString &name )
 {
-  mGroupStack.push( name );
-  if ( !name.isEmpty() )
-  {
-    mGroupPrefix += name;
-    mGroupPrefix += QLatin1Char( '/' );
-  }
+  start( name );
 }
 
 void QgsRuntimeProfiler::endGroup()
 {
-  if ( mGroupStack.isEmpty() )
+  end();
+}
+
+QStringList QgsRuntimeProfiler::childGroups( const QString &parent ) const
+{
+  QStringList res;
+  const int parentDepth = parent.split( '/' ).length();
+  for ( auto it = mProfileTimes.constBegin(); it != mProfileTimes.constEnd(); ++it )
   {
-    qWarning( "QgsSettings::endGroup: No matching beginGroup()" );
-    return;
-  }
+    if ( !parent.isEmpty() && !it->first.startsWith( parent + '/' ) )
+      continue;
+
+    if ( it->first.isEmpty() )
+      continue;
 
-  QString group = mGroupStack.pop();
-  int len = group.size();
-  if ( len > 0 )
-    mGroupPrefix.truncate( mGroupPrefix.size() - ( len + 1 ) );
+    const QStringList groups = it->first.split( '/' );
+    if ( parent.isEmpty() )
+    {
+      if ( !res.contains( groups.at( 0 ) ) )
+        res << groups.at( 0 );
+    }
+    else
+    {
+      if ( !res.contains( groups.at( parentDepth ) ) )
+        res << groups.at( parentDepth );
+    }
+  }
+  return res;
 }
 
 void QgsRuntimeProfiler::start( const QString &name )
 {
-  mProfileTime.restart();
-  mCurrentName = name;
+  mProfileTime.push( QElapsedTimer() );
+  mProfileTime.top().restart();
+  mCurrentName.push( name );
 }
 
 void QgsRuntimeProfiler::end()
 {
-  QString name = mCurrentName;
-  name.prepend( mGroupPrefix );
-  double timing = mProfileTime.elapsed() / 1000.0;
-  mProfileTimes.append( QPair<QString, double>( name, timing ) );
+  QString name;
+  for ( const QString &group : qgis::as_const( mCurrentName ) )
+  {
+    name += name.isEmpty() || name.right( 1 ) == '/' ? group : '/' + group;
+  }
+  mCurrentName.pop();
+
+  double timing = mProfileTime.top().elapsed() / 1000.0;
+  mProfileTime.pop();
+
+  mProfileTimes << qMakePair( name, timing );
   QgsDebugMsgLevel( QStringLiteral( "PROFILE: %1 - %2" ).arg( name ).arg( timing ), 2 );
 }
 
+double QgsRuntimeProfiler::profileTime( const QString &name ) const
+{
+  for ( auto it = mProfileTimes.constBegin(); it != mProfileTimes.constEnd(); ++it )
+  {
+    if ( it->first == name )
+      return it->second;
+  }
+  return -1;
+}
+
 void QgsRuntimeProfiler::clear()
 {
   mProfileTimes.clear();

src/core/qgsruntimeprofiler.h

@@ -41,13 +41,23 @@ class CORE_EXPORT QgsRuntimeProfiler
      * \brief Begin the group for the profiler. Groups will append {GroupName}/ to the
      * front of the profile tag set using start.
      * \param name The name of the group.
+     *
+     * \deprecated use start() instead
      */
-    void beginGroup( const QString &name );
+    Q_DECL_DEPRECATED void beginGroup( const QString &name ) SIP_DEPRECATED;
 
     /**
      * \brief End the current active group.
+     *
+     * \deprecated use end() instead
      */
-    void endGroup();
+    Q_DECL_DEPRECATED void endGroup() SIP_DEPRECATED;
+
+    /**
+     * Returns a list of all child groups with the specified \a parent.
+     * \since QGIS 3.14
+     */
+    QStringList childGroups( const QString &parent = QString() ) const;
 
     /**
      * \brief Start a profile event with the given name.
@@ -62,11 +72,10 @@ class CORE_EXPORT QgsRuntimeProfiler
     void end();
 
     /**
-     * Returns all the current profile times.
-     * \returns A list of profile event names and times.
-     * \note not available in Python bindings
+     * Returns the profile time for the specified \a name.
+     * \since QGIS 3.14
      */
-    const QList<QPair<QString, double > > profileTimes() const { return mProfileTimes; } SIP_SKIP
+    double profileTime( const QString &name ) const;
 
     /**
      * \brief clear Clear all profile data.
@@ -80,11 +89,10 @@ class CORE_EXPORT QgsRuntimeProfiler
     double totalTime();
 
   private:
-    QString mGroupPrefix;
-    QStack<QString> mGroupStack;
-    QElapsedTimer mProfileTime;
-    QString mCurrentName;
-    QList<QPair<QString, double > > mProfileTimes;
+
+    QStack< QElapsedTimer > mProfileTime;
+    QStack< QString > mCurrentName;
+    QList< QPair< QString, double > > mProfileTimes;
 };
 
 #endif // QGSRUNTIMEPROFILER_H