Add a memory pressure hint for NewFromMemoryCopy

To ensure that the GC knows the true cost of the image during collection.
kleisauke · Jan 29, 2020 · 7a7543f · 7a7543f
1 parent 1f4f1bf
commit 7a7543f
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Showing 3 changed files with 33 additions and 7 deletions.
diff --git a/src/NetVips/GObject.cs b/src/NetVips/GObject.cs
@@ -18,6 +18,11 @@ public class GObject : SafeHandle
         /// </summary>
         private readonly ICollection<GCHandle> _handles = new List<GCHandle>();
 
+        /// <summary>
+        /// Hint of how much native memory is actually occupied by the object.
+        /// </summary>
+        internal long MemoryPressure;
+
         // Handy for debugging
         // public static int NObjects;
 

diff --git a/src/NetVips/GValue.cs b/src/NetVips/GValue.cs
@@ -283,6 +283,7 @@ public void Set(object value)
             }
             else if (fundamental == GObjectType && value is GObject gObject)
             {
+                AddMemoryPressure(gObject.MemoryPressure);
                 Internal.GValue.SetObject(ref Struct, gObject);
             }
             else if (gtype == ArrayIntType)
@@ -351,6 +352,8 @@ public void Set(object value)
 
                     // the gvalue needs a ref on each of the images
                     image.ObjectRef();
+
+                    AddMemoryPressure(image.MemoryPressure);
                 }
             }
             else if (gtype == BlobType && value is VipsBlob blob)

diff --git a/src/NetVips/Image.cs b/src/NetVips/Image.cs
@@ -186,7 +186,13 @@ public static string FindLoadSource(Source source) =>
         /// </remarks>
         /// <param name="stream">The stream to test.</param>
         /// <returns>The name of the load operation, or <see langword="null"/>.</returns>
-        public static string FindLoadStream(Stream stream) => FindLoadSource(SourceStream.NewFromStream(stream));
+        public static string FindLoadStream(Stream stream)
+        {
+            using (var source = SourceStream.NewFromStream(stream))
+            {
+                return FindLoadSource(source);
+            }
+        }
 
         #endregion
 
@@ -491,8 +497,14 @@ public static Image NewFromStream(
             string strOptions = "",
             string access = null,
             bool? fail = null,
-            VOption kwargs = null) =>
-            NewFromSource(SourceStream.NewFromStream(stream), strOptions, access, fail, kwargs);
+            VOption kwargs = null)
+        {
+            using (var source = SourceStream.NewFromStream(stream))
+            {
+                return NewFromSource(source, strOptions, access, fail, kwargs);
+            }
+        }
+
 
         /// <summary>
         /// Create an image from a 2D array.
@@ -707,7 +719,7 @@ public static Image NewFromMemoryCopy(
                 throw new VipsException("unable to make image from memory");
             }
 
-            return new Image(vi);
+            return new Image(vi) { MemoryPressure = (long)size };
         }
 
         /// <summary>
@@ -815,7 +827,7 @@ public Image CopyMemory()
                 throw new VipsException("unable to copy to memory");
             }
 
-            return new Image(vi);
+            return new Image(vi) { MemoryPressure = MemoryPressure };
         }
 
         #endregion
@@ -999,8 +1011,14 @@ public void WriteToTarget(Target target, string formatString, VOption kwargs = n
         /// <param name="formatString">The suffix, plus any string-form arguments.</param>
         /// <param name="kwargs">Optional options that depend on the save operation.</param>
         /// <exception cref="VipsException">If unable to write to stream.</exception>
-        public void WriteToStream(Stream stream, string formatString, VOption kwargs = null) =>
-            WriteToTarget(TargetStream.NewFromStream(stream), formatString, kwargs);
+        public void WriteToStream(Stream stream, string formatString, VOption kwargs = null)
+        {
+            using (var target = TargetStream.NewFromStream(stream))
+            {
+                WriteToTarget(target, formatString, kwargs);
+            }
+        }
+
 
         /// <summary>
         /// Write the image to memory as a simple, unformatted C-style array.