Index: lldb/source/Host/macosx/objcxx/Host.mm
===================================================================
--- lldb/source/Host/macosx/objcxx/Host.mm
+++ lldb/source/Host/macosx/objcxx/Host.mm
@@ -330,7 +330,23 @@
 #if !TARGET_OS_OSX
   return false;
 #else // !TARGET_OS_OSX
-  // We attach this to an 'odoc' event to specify a particular selection
+  Log *log = GetLog(LLDBLog::Host);
+
+  const std::string file_path = file_spec.GetPath();
+
+  LLDB_LOG(log, "Sending {0}:{1} to external editor", file_path, line_no);
+
+  if (file_path.empty())
+    return false;
+
+  CFCString file_cfstr(file_path.c_str(), kCFStringEncodingUTF8);
+  CFCReleaser<CFURLRef> file_URL(::CFURLCreateWithFileSystemPath(
+      NULL, file_cfstr.get(), kCFURLPOSIXPathStyle, false));
+
+  if (!file_URL.get())
+    return false;
+
+  // Create a new Apple Event descriptor.
   typedef struct {
     int16_t reserved0; // must be zero
     int16_t fLineNumber;
@@ -340,18 +356,7 @@
     uint32_t reserved2; // must be zero
   } BabelAESelInfo;
 
-  Log *log = GetLog(LLDBLog::Host);
-  char file_path[PATH_MAX];
-  file_spec.GetPath(file_path, PATH_MAX);
-  CFCString file_cfstr(file_path, kCFStringEncodingUTF8);
-  CFCReleaser<CFURLRef> file_URL(::CFURLCreateWithFileSystemPath(
-      NULL, file_cfstr.get(), kCFURLPOSIXPathStyle, false));
-
-  LLDB_LOGF(log,
-            "Sending source file: \"%s\" and line: %d to external editor.\n",
-            file_path, line_no);
-
-  long error;
+  // We attach this to an 'odoc' event to specify a particular selection.
   BabelAESelInfo file_and_line_info = {
       0,                      // reserved0
       (int16_t)(line_no - 1), // fLineNumber (zero based line number)
@@ -362,60 +367,62 @@
   };
 
   AEKeyDesc file_and_line_desc;
-
-  error = ::AECreateDesc(typeUTF8Text, &file_and_line_info,
-                         sizeof(file_and_line_info),
-                         &(file_and_line_desc.descContent));
+  file_and_line_desc.descKey = keyAEPosition;
+  long error = ::AECreateDesc(/*typeCode=*/typeUTF8Text,
+                              /*dataPtr=*/&file_and_line_info,
+                              /*dataSize=*/sizeof(file_and_line_info),
+                              /*result=*/&(file_and_line_desc.descContent));
 
   if (error != noErr) {
-    LLDB_LOGF(log, "Error creating AEDesc: %ld.\n", error);
+    LLDB_LOG(log, "Creating Apple Event descriptor failed: error {0}", error);
     return false;
   }
 
-  file_and_line_desc.descKey = keyAEPosition;
+  // Deallocate the descriptor on exit.
+  auto on_exit = llvm::make_scope_exit(
+      [&]() { AEDisposeDesc(&(file_and_line_desc.descContent)); });
 
-  static std::string g_app_name;
-  static FSRef g_app_fsref;
+  static std::optional<FSRef> g_app_fsref;
+  static std::once_flag g_once_flag;
+  std::call_once(g_once_flag, [&]() {
+    if (const char *external_editor = ::getenv("LLDB_EXTERNAL_EDITOR")) {
+      LLDB_LOG(log, "Looking for external editor: {0}", external_editor);
 
+      FSRef app_fsref;
+      CFCString editor_name(external_editor, kCFStringEncodingUTF8);
+      error = ::LSFindApplicationForInfo(
+          /*inCreator=*/kLSUnknownCreator, /*inBundleID=*/NULL,
+          /*inName=*/editor_name.get(), /*outAppRef=*/&app_fsref,
+          /*outAppURL=*/NULL);
+      if (error == noErr) {
+        g_app_fsref = app_fsref;
+      } else {
+        LLDB_LOG(log, "Could not find external editor \"{0}\": error {1}",
+                 external_editor, error);
+      }
+    }
+  });
+
+  // Build app launch parameters.
   LSApplicationParameters app_params;
   ::memset(&app_params, 0, sizeof(app_params));
   app_params.flags =
       kLSLaunchDefaults | kLSLaunchDontAddToRecents | kLSLaunchDontSwitch;
-
-  char *external_editor = ::getenv("LLDB_EXTERNAL_EDITOR");
-
-  if (external_editor) {
-    LLDB_LOGF(log, "Looking for external editor \"%s\".\n", external_editor);
-
-    if (g_app_name.empty() ||
-        strcmp(g_app_name.c_str(), external_editor) != 0) {
-      CFCString editor_name(external_editor, kCFStringEncodingUTF8);
-      error = ::LSFindApplicationForInfo(kLSUnknownCreator, NULL,
-                                         editor_name.get(), &g_app_fsref, NULL);
-
-      // If we found the app, then store away the name so we don't have to
-      // re-look it up.
-      if (error != noErr) {
-        LLDB_LOGF(log,
-                  "Could not find External Editor application, error: %ld.\n",
-                  error);
-        return false;
-      }
-    }
-    app_params.application = &g_app_fsref;
-  }
+  if (g_app_fsref)
+    app_params.application = &(g_app_fsref.value());
 
   ProcessSerialNumber psn;
-  CFCReleaser<CFArrayRef> file_array(
-      CFArrayCreate(NULL, (const void **)file_URL.ptr_address(false), 1, NULL));
-  error = ::LSOpenURLsWithRole(file_array.get(), kLSRolesAll,
-                               &file_and_line_desc, &app_params, &psn, 1);
-
-  AEDisposeDesc(&(file_and_line_desc.descContent));
+  std::array<CFURLRef, 1> file_array = {file_URL.get()};
+  CFCReleaser<CFArrayRef> cf_array(
+      CFArrayCreate(/*allocator=*/NULL, /*values=*/(const void **)&file_array,
+                    /*numValues*/ 1, /*callBacks=*/NULL));
+  error = ::LSOpenURLsWithRole(
+      /*inURLs=*/cf_array.get(), /*inRole=*/kLSRolesAll,
+      /*inAEParam=*/&file_and_line_desc,
+      /*inAppParams=*/&app_params, /*outPSNs=*/&psn, /*inMaxPSNCount=*/1);
 
   if (error != noErr) {
-    LLDB_LOGF(log, "LSOpenURLsWithRole failed, error: %ld.\n", error);
-
+    LLDB_LOG(log, "LSOpenURLsWithRole failed: error {0}", error);
     return false;
   }