RDART-1045: Expose setrlimit ios (#1700)

* Expose setrlimit on iOS

* Use setrlimit when running test on iOS

* Revert "Run iOS test on macos-12"

This reverts commit 1e6a379.

* Throw and handle exceptions on error for good measure

Author: Kasper Overgård Nielsen

.github/workflows/ci.yml

@@ -302,7 +302,7 @@ jobs:
       differentiator: fi${{ github.run_id }}${{ github.run_attempt }}
 
   flutter-tests-ios:
-    runs-on: macos-12
+    runs-on: macos-14
     name: Flutter Tests iOS
     timeout-minutes: 45
     needs:

packages/realm_dart/lib/src/native/realm_bindings.dart

@@ -3971,6 +3971,33 @@ class RealmLibrary {
   late final _realm_dart_scheduler_invoke = _realm_dart_scheduler_invokePtr
       .asFunction<void Function(int, ffi.Pointer<ffi.Void>)>();
 
+  /// implemented for iOS only (for now - valid for all posix)
+  /// /**
+  ///  * Set the soft limit on number of open files
+  ///  * @param limit The requested limit. If less than zero no attempt is made.
+  ///  * @param[out] out_limit The actual limit set.
+  ///  *
+  ///  * @return true if no error occurred.
+  ///  *
+  ///  * @throws RLM_ERR_FILE_PERMISSION_DENIED if the operation was not permitted.
+  ///  */
+  bool realm_dart_set_and_get_rlimit(
+    int limit,
+    ffi.Pointer<ffi.Long> out_limit,
+  ) {
+    return _realm_dart_set_and_get_rlimit(
+      limit,
+      out_limit,
+    );
+  }
+
+  late final _realm_dart_set_and_get_rlimitPtr = _lookup<
+          ffi
+          .NativeFunction<ffi.Bool Function(ffi.Long, ffi.Pointer<ffi.Long>)>>(
+      'realm_dart_set_and_get_rlimit');
+  late final _realm_dart_set_and_get_rlimit = _realm_dart_set_and_get_rlimitPtr
+      .asFunction<bool Function(int, ffi.Pointer<ffi.Long>)>();
+
   bool realm_dart_sync_after_reset_handler_callback(
     ffi.Pointer<ffi.Void> userdata,
     ffi.Pointer<realm_t> before_realm,
@@ -11833,6 +11860,11 @@ class _SymbolAddresses {
           .NativeFunction<ffi.Void Function(ffi.Uint64, ffi.Pointer<ffi.Void>)>>
       get realm_dart_scheduler_invoke =>
           _library._realm_dart_scheduler_invokePtr;
+  ffi.Pointer<
+          ffi
+          .NativeFunction<ffi.Bool Function(ffi.Long, ffi.Pointer<ffi.Long>)>>
+      get realm_dart_set_and_get_rlimit =>
+          _library._realm_dart_set_and_get_rlimitPtr;
   ffi.Pointer<
       ffi.NativeFunction<
           ffi.Bool Function(

packages/realm_dart/lib/src/native/realm_core.dart

@@ -188,4 +188,12 @@ class RealmCore {
   String _getFilesPath() {
     return realmLib.realm_dart_get_files_path().cast<Utf8>().toRealmDartString()!;
   }
+
+  int setAndGetRLimit(int limit) {
+    return using((arena) {
+      final outLimit = arena<Long>();
+      realmLib.realm_dart_set_and_get_rlimit(limit, outLimit).raiseLastErrorIfFalse();
+      return outLimit.value;
+    });
+  }
 }

packages/realm_dart/src/ios/platform.mm

@@ -19,9 +19,12 @@
 #import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>
 
-#include <string>
 #include "../realm_dart.h"
-#import <sys/utsname.h>
+#include <string>
+#include <sys/utsname.h>
+#include <sys/resource.h>
+#include <system_error>
+#include <realm/object-store/c_api/util.hpp>
 
 static std::string filesDir;
 static std::string deviceModel;
@@ -48,7 +51,6 @@
     }
 }
 
-
 RLM_API const char* realm_dart_get_files_path() {
     if (filesDir == "") {
         filesDir = default_realm_file_directory();
@@ -74,3 +76,33 @@
 
     return deviceVersion.c_str();
 }
+
+namespace {
+    using namespace realm::c_api;
+
+    rlimit get_rlimit() {
+        rlimit rlim;
+        int status = getrlimit(RLIMIT_NOFILE, &rlim);
+        if (status < 0)
+            throw std::system_error(errno, std::system_category(), "getrlimit() failed");
+        return rlim;
+    }
+
+    long set_and_get_rlimit(long limit) {
+        if (limit > 0) {
+            auto rlim = get_rlimit();
+            rlim.rlim_cur = limit;
+            int status = setrlimit(RLIMIT_NOFILE, &rlim);
+            if (status < 0)
+                throw std::system_error(errno, std::system_category(), "setrlimit() failed");
+        }
+        return get_rlimit().rlim_cur;
+    }
+}
+
+RLM_API bool realm_dart_set_and_get_rlimit(long limit, long* out_limit) {
+    return wrap_err([&]() {
+        *out_limit = set_and_get_rlimit(limit);
+        return true;
+    });
+}

packages/realm_dart/src/realm_dart.h

@@ -36,6 +36,18 @@ RLM_API const char* realm_dart_get_device_version();
 // implemented for Android only
 RLM_API const char* realm_dart_get_bundle_id();
 
+// implemented for iOS only (for now - valid for all posix)
+/**
+ * Set the soft limit on number of open files
+ * @param limit The requested limit. If less than zero no attempt is made.
+ * @param[out] out_limit The actual limit set.
+ *
+ * @return true if no error occurred.
+ *
+ * @throws RLM_ERR_FILE_PERMISSION_DENIED if the operation was not permitted.
+ */
+RLM_API bool realm_dart_set_and_get_rlimit(long limit, long* out_limit);
+
 RLM_API const char* realm_get_library_cpu_arch();
 
 typedef struct realm_dart_userdata_async* realm_dart_userdata_async_t;

packages/realm_dart/test/test.dart

@@ -430,6 +430,11 @@ void setupTests() {
       printOnFailure('${record.category} ${record.level.name}: ${record.message}');
     });
 
+    if (Platform.isIOS) {
+      final maxFiles = realmCore.setAndGetRLimit(1024);
+      print('Max files: $maxFiles');
+    }
+
     // Enable this to print platform info, including current PID
     _printPlatformInfo();
   });