IJPL-170710 Fixed memory statistics in bcc for mac.

It showed the cached part as used before. Now we exclude reclaimable cahce from the used part.

GitOrigin-RevId: 513a110a3952521413961ecb5aac7b99c0d0c287

platform/util/src/com/intellij/openapi/util/io/MemoryUtil.java

@@ -0,0 +1,68 @@
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.openapi.util.io;
+
+import com.sun.jna.*;
+import com.sun.jna.ptr.IntByReference;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Arrays;
+import java.util.List;
+
+@ApiStatus.Internal
+public final class MemoryUtil {
+
+  @Nullable
+  public static Long getUnusedMemory() {
+    IntByReference pageSizeRef = new IntByReference();
+    if (LibC.INSTANCE.host_page_size(LibC.INSTANCE.mach_host_self(), pageSizeRef) == -1) {
+      return null;
+    }
+    long pageSize = pageSizeRef.getValue();
+    VmStatistics64 stats = new VmStatistics64();
+    IntByReference count = new IntByReference(stats.size() / 4);
+    if(LibC.INSTANCE.host_statistics64(LibC.INSTANCE.mach_host_self(), LibC.HOST_VM_INFO64, stats, count) == -1){
+      return null;
+    }
+
+    return (stats.free_count + stats.inactive_count) * pageSize;
+  }
+
+  private interface LibC extends Library {
+    LibC INSTANCE = Native.load(LibC.class);
+
+    int HOST_VM_INFO64 = 2;
+
+    int host_statistics64(int host, int flavor, Structure stats, IntByReference count);
+
+    int host_page_size(int host, IntByReference pageSize);
+
+    int mach_host_self();
+  }
+
+  public static class VmStatistics64 extends Structure {
+    public int free_count;
+    public int active_count;
+    public int inactive_count;
+    public int wire_count;
+    public int zero_fill_count;
+    public int reactivations;
+    public int pageins;
+    public int pageouts;
+    public int faults;
+    public int cow_faults;
+    public int lookups;
+    public int hits;
+    public int purges;
+    public int speculative_count;
+
+    @Override
+    protected List<String> getFieldOrder() {
+      return Arrays.asList(
+        "free_count", "active_count", "inactive_count", "wire_count",
+        "zero_fill_count", "reactivations", "pageins", "pageouts",
+        "faults", "cow_faults", "lookups", "hits", "purges", "speculative_count"
+      );
+    }
+  }
+}