From fa222567170ea09dd1cca9fb7998c601720c2fb8 Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Mon, 20 Mar 2023 14:49:49 +1000
Subject: [PATCH] Allow temporary folder location to be overridden through
 QgsProcessingContext

---
 .../processing/qgsprocessingcontext.sip.in    | 24 ++++++++++++++++++
 src/core/processing/qgsprocessingcontext.cpp  | 10 ++++++++
 src/core/processing/qgsprocessingcontext.h    | 25 +++++++++++++++++++
 src/core/processing/qgsprocessingutils.cpp    |  8 +++++-
 4 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/python/core/auto_generated/processing/qgsprocessingcontext.sip.in b/python/core/auto_generated/processing/qgsprocessingcontext.sip.in
index 87e2decf09a..48ba8ece037 100644
--- a/python/core/auto_generated/processing/qgsprocessingcontext.sip.in
+++ b/python/core/auto_generated/processing/qgsprocessingcontext.sip.in
@@ -585,6 +585,30 @@ Sets the logging ``level`` for algorithms to use when pushing feedback messages
 .. seealso:: :py:func:`logLevel`
 
 .. versionadded:: 3.20
+%End
+
+    QString temporaryFolder() const;
+%Docstring
+Returns the (optional) temporary folder to use when running algorithms.
+
+If set, this overrides the standard global Processing temporary folder and should be used
+for all temporary files created during algorithm execution.
+
+.. seealso:: :py:func:`setTemporaryFolder`
+
+.. versionadded:: 3.32
+%End
+
+    void setTemporaryFolder( const QString &folder );
+%Docstring
+Sets the (optional) temporary ``folder`` to use when running algorithms.
+
+If set, this overrides the standard global Processing temporary folder and should be used
+for all temporary files created during algorithm execution.
+
+.. seealso:: :py:func:`temporaryFolder`
+
+.. versionadded:: 3.32
 %End
 
     QVariantMap exportToMap() const;
diff --git a/src/core/processing/qgsprocessingcontext.cpp b/src/core/processing/qgsprocessingcontext.cpp
index be0d7495a9b..50f3ffb093e 100644
--- a/src/core/processing/qgsprocessingcontext.cpp
+++ b/src/core/processing/qgsprocessingcontext.cpp
@@ -147,6 +147,16 @@ void QgsProcessingContext::setLogLevel( LogLevel level )
   mLogLevel = level;
 }
 
+QString QgsProcessingContext::temporaryFolder() const
+{
+  return mTemporaryFolderOverride;
+}
+
+void QgsProcessingContext::setTemporaryFolder( const QString &folder )
+{
+  mTemporaryFolderOverride = folder;
+}
+
 QVariantMap QgsProcessingContext::exportToMap() const
 {
   QVariantMap res;
diff --git a/src/core/processing/qgsprocessingcontext.h b/src/core/processing/qgsprocessingcontext.h
index 3ebff682b4e..235900b8e32 100644
--- a/src/core/processing/qgsprocessingcontext.h
+++ b/src/core/processing/qgsprocessingcontext.h
@@ -100,6 +100,7 @@ class CORE_EXPORT QgsProcessingContext
       mDistanceUnit = other.mDistanceUnit;
       mAreaUnit = other.mAreaUnit;
       mLogLevel = other.mLogLevel;
+      mTemporaryFolderOverride = other.mTemporaryFolderOverride;
     }
 
     /**
@@ -657,6 +658,28 @@ class CORE_EXPORT QgsProcessingContext
      */
     void setLogLevel( LogLevel level );
 
+    /**
+     * Returns the (optional) temporary folder to use when running algorithms.
+     *
+     * If set, this overrides the standard global Processing temporary folder and should be used
+     * for all temporary files created during algorithm execution.
+     *
+     * \see setTemporaryFolder()
+     * \since QGIS 3.32
+     */
+    QString temporaryFolder() const;
+
+    /**
+     * Sets the (optional) temporary \a folder to use when running algorithms.
+     *
+     * If set, this overrides the standard global Processing temporary folder and should be used
+     * for all temporary files created during algorithm execution.
+     *
+     * \see temporaryFolder()
+     * \since QGIS 3.32
+     */
+    void setTemporaryFolder( const QString &folder );
+
     /**
      * Exports the context's settings to a variant map.
      *
@@ -713,6 +736,8 @@ class CORE_EXPORT QgsProcessingContext
 
     LogLevel mLogLevel = DefaultLevel;
 
+    QString mTemporaryFolderOverride;
+
 #ifdef SIP_RUN
     QgsProcessingContext( const QgsProcessingContext &other );
 #endif
diff --git a/src/core/processing/qgsprocessingutils.cpp b/src/core/processing/qgsprocessingutils.cpp
index fdc039dd7b0..cd4a6105bc8 100644
--- a/src/core/processing/qgsprocessingutils.cpp
+++ b/src/core/processing/qgsprocessingutils.cpp
@@ -1037,7 +1037,13 @@ QString QgsProcessingUtils::tempFolder( const QgsProcessingContext *context )
   static QString sFolder;
   static QMutex sMutex;
   QMutexLocker locker( &sMutex );
-  const QString basePath = QgsProcessing::settingsTempPath->value();
+  QString basePath;
+
+  if ( context )
+    basePath = context->temporaryFolder();
+  if ( basePath.isEmpty() )
+    basePath = QgsProcessing::settingsTempPath->value();
+
   if ( basePath.isEmpty() )
   {
     // default setting -- automatically create a temp folder