Implement FileOpen dialog in UserInteractions (#839)

There are increasingly cases where we want to prompt users for a file.
Rather than write this in VSTGUI I'm using the OS specific APIs behind
a UserInteraction common point. As of this writing Mac and Windows work but
ignore the options for starting directory and filter; and Linux returns a
UserError.

Since this move required me to move to cocoa for Mac UserInteractions,
also set up the .clang-format file to work properly with objective c

Closes #829 (but will require us to open another issue for linux and the
undone parts of the API). Pushing this now so I can use it for scale file
opening in the tuning issue.

.clang-format

@@ -1,4 +1,4 @@
-
+---
 Language: Cpp
 BasedOnStyle: LLVM
 IndentWidth: 3
@@ -29,4 +29,36 @@ BinPackParameters: false
 AllowShortIfStatementsOnASingleLine: false
 AllowShortFunctionsOnASingleLine: false
 AlwaysBreakAfterReturnType: None
-BreakBeforeTernaryOperators: true
+BreakBeforeTernaryOperators: true
+---
+Language: ObjC
+BasedOnStyle: LLVM
+IndentWidth: 3
+CompactNamespaces: true
+FixNamespaceComments: true
+PointerAlignment: Left
+SortIncludes: false
+Standard: Cpp11
+IndentCaseLabels: false
+MaxEmptyLinesToKeep: 1
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterClass: true
+  AfterFunction: true
+  AfterControlStatement: true
+  AfterEnum: true
+  AfterStruct: true
+  AfterNamespace: true
+  SplitEmptyFunction: false
+  AfterUnion: true
+  BeforeCatch: true
+  BeforeElse: true
+
+AccessModifierOffset: -3
+ColumnLimit: 100
+BinPackParameters: false
+
+AllowShortIfStatementsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: false
+AlwaysBreakAfterReturnType: None
+BreakBeforeTernaryOperators: true

src/common/UserInteractions.h

@@ -14,6 +14,7 @@
 
 #include <string>
 #include <atomic>
+#include <functional>
 #include "SurgeError.h"
 
 class SurgeGUIEditor;
@@ -48,6 +49,11 @@ void openURL(const std::string &url);
 // etc)
 void openFolderInFileBrowser(const std::string& folder);
 
+// Prompt for a file to open; call the callback if you pick one
+void promptFileOpenDialog(const std::string& initialDirectory,
+                          const std::string& filterSuffix,
+                          std::function<void(std::string)> callbackOnOpen,
+                          SurgeGUIEditor* guiEditor = nullptr);
 };
 
 };

src/headless/UserInteractionsHeadless.cpp

@@ -34,6 +34,14 @@ void openURL(const std::string &url)
 {
 }
 
+void promptFileOpenDialog(const std::string& initialDirectory,
+                          const std::string& filterSuffix,
+                          std::function<void(std::string)> callbackOnOpen,
+                          SurgeGUIEditor* guiEditor)
+{
+   UserInteractions::promptError("OpenFileDialog is unimplemented in this version of Surge. Sorry!",
+                                 "Unimplemented Function", guiEditor);
+}
 };
 
 };

src/linux/UserInteractionsLinux.cpp

@@ -50,6 +50,14 @@ void openFolderInFileBrowser(const std::string& folder)
    UserInteractions::openURL(url);
 }
 
+void promptFileOpenDialog(const std::string& initialDirectory,
+                          const std::string& filterSuffix,
+                          std::function<void(std::string)> callbackOnOpen,
+                          SurgeGUIEditor* guiEditor)
+{
+   UserInteractions::promptError("OpenFileDialog is unimplemented in this version of Surge. Sorry!",
+                                 "Unimplemented Function", guiEditor);
+}
 };
 
 };

src/mac/UserInteractionsMac.mm

@@ -0,0 +1,100 @@
+#include "UserInteractions.h"
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreServices/CoreServices.h>
+#include <ApplicationServices/ApplicationServices.h>
+#include <AppKit/AppKit.h>
+
+namespace Surge
+{
+
+namespace UserInteractions
+{
+
+void promptError(const std::string& message, const std::string& title, SurgeGUIEditor* guiEditor)
+{
+   CFStringRef cfT =
+       CFStringCreateWithCString(kCFAllocatorDefault, title.c_str(), kCFStringEncodingUTF8);
+   CFStringRef cfM =
+       CFStringCreateWithCString(kCFAllocatorDefault, message.c_str(), kCFStringEncodingUTF8);
+
+   SInt32 nRes = 0;
+   CFUserNotificationRef pDlg = NULL;
+   const void* keys[] = {kCFUserNotificationAlertHeaderKey, kCFUserNotificationAlertMessageKey};
+   const void* vals[] = {cfT, cfM};
+
+   CFDictionaryRef dict =
+       CFDictionaryCreate(0, keys, vals, sizeof(keys) / sizeof(*keys),
+                          &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
+
+   pDlg = CFUserNotificationCreate(kCFAllocatorDefault, 0, kCFUserNotificationStopAlertLevel, &nRes,
+                                   dict);
+
+   CFRelease(cfT);
+   CFRelease(cfM);
+}
+
+void promptError(const Surge::Error& error, SurgeGUIEditor* guiEditor)
+{
+   promptError(error.getMessage(), error.getTitle());
+}
+
+MessageResult
+promptOKCancel(const std::string& message, const std::string& title, SurgeGUIEditor* guiEditor)
+{
+   CFStringRef cfT =
+       CFStringCreateWithCString(kCFAllocatorDefault, title.c_str(), kCFStringEncodingUTF8);
+   CFStringRef cfM =
+       CFStringCreateWithCString(kCFAllocatorDefault, message.c_str(), kCFStringEncodingUTF8);
+
+   CFOptionFlags responseFlags;
+   CFUserNotificationDisplayAlert(0, kCFUserNotificationPlainAlertLevel, 0, 0, 0, cfT, cfM,
+                                  CFSTR("OK"), CFSTR("Cancel"), 0, &responseFlags);
+
+   CFRelease(cfT);
+   CFRelease(cfM);
+
+   if ((responseFlags & 0x3) != kCFUserNotificationDefaultResponse)
+      return UserInteractions::CANCEL;
+   return UserInteractions::OK;
+}
+
+void openURL(const std::string& url_str)
+{
+   CFURLRef url = CFURLCreateWithBytes(NULL,                    // allocator
+                                       (UInt8*)url_str.c_str(), // URLBytes
+                                       url_str.length(),        // length
+                                       kCFStringEncodingASCII,  // encoding
+                                       NULL                     // baseURL
+   );
+   LSOpenCFURLRef(url, 0);
+   CFRelease(url);
+}
+
+void openFolderInFileBrowser(const std::string& folder)
+{
+   std::string url = "file://" + folder;
+   UserInteractions::openURL(url);
+}
+
+void promptFileOpenDialog(const std::string& initialDirectory,
+                          const std::string& filterSuffix,
+                          std::function<void(std::string)> callbackOnOpen,
+                          SurgeGUIEditor* guiEditor)
+{
+   // FIXME TODO - support the filterSuffix and initialDirectory
+   NSOpenPanel* panel = [NSOpenPanel openPanel];
+
+   [panel beginWithCompletionHandler:^(NSInteger result) {
+     if (result == NSFileHandlingPanelOKButton)
+     {
+        NSURL* theDoc = [[panel URLs] objectAtIndex:0];
+        NSString* path = [theDoc path];
+        std::string pstring([path UTF8String]);
+        callbackOnOpen(pstring);
+     }
+   }];
+}
+
+};
+
+};

src/windows/UserInteractionsWin.cpp

@@ -1,4 +1,5 @@
 #include <Windows.h>
+#include <Commdlg.h>
 #include <string>
 #include "UserInteractions.h"
 #include "SurgeGUIEditor.h"
@@ -46,6 +47,33 @@ void openFolderInFileBrowser(const std::string& folder)
    UserInteractions::openURL(url);
 }
 
+void promptFileOpenDialog(const std::string& initialDirectory,
+                          const std::string& filterSuffix,
+                          std::function<void(std::string)> callbackOnOpen,
+                          SurgeGUIEditor* guiEditor)
+{
+   // With many thanks to
+   // https://www.daniweb.com/programming/software-development/code/217307/a-simple-getopenfilename-example
+   char szFile[1024];
+   OPENFILENAME ofn;
+   ZeroMemory(&ofn, sizeof(ofn));
+   ofn.lStructSize = sizeof(ofn);
+   ofn.hwndOwner = NULL;
+   ofn.lpstrFile = szFile;
+   ofn.lpstrFile[0] = '\0';
+   ofn.nMaxFile = sizeof(szFile);
+   ofn.lpstrFilter = "All\0*.*\0";
+   ofn.nFilterIndex = 0;
+   ofn.lpstrFileTitle = NULL;
+   ofn.nMaxFileTitle = 0;
+   ofn.lpstrInitialDir = NULL;
+   ofn.Flags = OFN_PATHMUSTEXIST | OFN_FILEMUSTEXIST;
+
+   if (GetOpenFileName(&ofn))
+   {
+      callbackOnOpen(ofn.lpstrFile);
+   }
+}
 };
 
 };