Fix crash or hang on macOS on arm64 when opening a file picker

There is no reason to not mention the NSOpenSavePanelDelegate protocol
that AquaFilePickerDelegate implements.

The way we used objc_msgSend() caused a crash or hang. (I saw both,
depending on whether the code was built for debugging or not). For
some reason we used to cast it to a function with variadic parameters
like:

    reinterpret_cast<id (*)(id, SEL, ...)>(objc_msgSend)(
        m_pDialog, @selector(setDelegate:), m_pDelegate);

This does not work in arm64 code on macOS. (See
https://developer.apple.com/documentation/apple_silicon/addressing_architectural_differences_in_your_macos_code?language=objc
, the "Don't Redeclare a Function to Have Variable Parameters"
section.)

We could have replaced the ellipsis with the actual type of the first
real parameter in this call, or just "id" would have worked fine. But
it is much simpler to just do what we mean directly:

    [m_pDialog setDelegate:m_pDelegate];

I need to look through the code for other places where we have used
objc_msgSend() in a similar fashion.

Change-Id: Ia93b2007ed8f263eaf99d604a3c88e857efbb421
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107257
Tested-by: Jenkins
Reviewed-by: Tor Lillqvist <tml@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107326
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

2 files changed, 2 insertions, 8 deletions

diff --git a/fpicker/source/aqua/AquaFilePickerDelegate.hxx b/fpicker/source/aqua/AquaFilePickerDelegate.hxx
index eb7e1ce402e6..fb158cd67633 100644
--- a/fpicker/source/aqua/AquaFilePickerDelegate.hxx
+++ b/fpicker/source/aqua/AquaFilePickerDelegate.hxx
@@ -27,7 +27,7 @@
 class SalAquaFilePicker;
 class FilterHelper;
 
-@interface AquaFilePickerDelegate : NSObject
+@interface AquaFilePickerDelegate : NSObject <NSOpenSavePanelDelegate>
 {
     SalAquaFilePicker* filePicker;
     FilterHelper* filterHelper;
diff --git a/fpicker/source/aqua/SalAquaFilePicker.mm b/fpicker/source/aqua/SalAquaFilePicker.mm
index ac54fca0cc98..3fbe8e7c949a 100644
--- a/fpicker/source/aqua/SalAquaFilePicker.mm
+++ b/fpicker/source/aqua/SalAquaFilePicker.mm
@@ -155,13 +155,7 @@ sal_Int16 SAL_CALL SalAquaFilePicker::execute()
 
     //Set the delegate to be notified of certain events
 
-    // I don't know why, but with gcc 4.2.1, this line results in the warning:
-    // class 'AquaFilePickerDelegate' does not implement the 'NSOpenSavePanelDelegate' protocol
-    // So instead of:
-    // [m_pDialog setDelegate:m_pDelegate];
-    // do:
-    reinterpret_cast<id (*)(id, SEL, ...)>(objc_msgSend)(
-        m_pDialog, @selector(setDelegate:), m_pDelegate);
+    [m_pDialog setDelegate:m_pDelegate];
 
     int nStatus = runandwaitforresult();