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-rw-r--r--src/mscorlib/corefx/Interop/Unix/System.Globalization.Native/Interop.Utils.cs52
1 files changed, 52 insertions, 0 deletions
diff --git a/src/mscorlib/corefx/Interop/Unix/System.Globalization.Native/Interop.Utils.cs b/src/mscorlib/corefx/Interop/Unix/System.Globalization.Native/Interop.Utils.cs
new file mode 100644
index 0000000000..33b10c0d74
--- /dev/null
+++ b/src/mscorlib/corefx/Interop/Unix/System.Globalization.Native/Interop.Utils.cs
@@ -0,0 +1,52 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Text;
+
+internal static partial class Interop
+{
+ /// <summary>
+ /// Helper for making interop calls that return a string, but we don't know
+ /// the correct size of buffer to make. So invoke the interop call with an
+ /// increasing buffer until the size is big enough.
+ /// </summary>
+ internal static bool CallStringMethod<TArg1, TArg2, TArg3>(
+ Func<TArg1, TArg2, TArg3, StringBuilder, GlobalizationInterop.ResultCode> interopCall,
+ TArg1 arg1,
+ TArg2 arg2,
+ TArg3 arg3,
+ out string result)
+ {
+ const int initialStringSize = 80;
+ const int maxDoubleAttempts = 5;
+
+ StringBuilder stringBuilder = StringBuilderCache.Acquire(initialStringSize);
+
+ for (int i = 0; i < maxDoubleAttempts; i++)
+ {
+ GlobalizationInterop.ResultCode resultCode = interopCall(arg1, arg2, arg3, stringBuilder);
+
+ if (resultCode == GlobalizationInterop.ResultCode.Success)
+ {
+ result = StringBuilderCache.GetStringAndRelease(stringBuilder);
+ return true;
+ }
+ else if (resultCode == GlobalizationInterop.ResultCode.InsufficentBuffer)
+ {
+ // increase the string size and loop
+ stringBuilder.EnsureCapacity(stringBuilder.Capacity * 2);
+ }
+ else
+ {
+ // if there is an unknown error, don't proceed
+ break;
+ }
+ }
+
+ StringBuilderCache.Release(stringBuilder);
+ result = null;
+ return false;
+ }
+}