1 files changed, 133 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/cache/CacheInfo.java b/java/com/google/gerrit/server/cache/CacheInfo.java
new file mode 100644
index 0000000000..d6eb065339
--- /dev/null
+++ b/java/com/google/gerrit/server/cache/CacheInfo.java
@@ -0,0 +1,133 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheStats;
+
+public class CacheInfo {
+
+  public String name;
+  public CacheType type;
+  public EntriesInfo entries;
+  public String averageGet;
+  public HitRatioInfo hitRatio;
+
+  public CacheInfo(Cache<?, ?> cache) {
+    this(null, cache);
+  }
+
+  public CacheInfo(String name, Cache<?, ?> cache) {
+    this.name = name;
+
+    CacheStats stat = cache.stats();
+
+    entries = new EntriesInfo();
+    entries.setMem(cache.size());
+
+    averageGet = duration(stat.averageLoadPenalty());
+
+    hitRatio = new HitRatioInfo();
+    hitRatio.setMem(stat.hitCount(), stat.requestCount());
+
+    if (cache instanceof PersistentCache) {
+      type = CacheType.DISK;
+      PersistentCache.DiskStats diskStats = ((PersistentCache) cache).diskStats();
+      entries.setDisk(diskStats.size());
+      entries.setSpace(diskStats.space());
+      hitRatio.setDisk(diskStats.hitCount(), diskStats.requestCount());
+    } else {
+      type = CacheType.MEM;
+    }
+  }
+
+  private static String duration(double ns) {
+    if (ns < 0.5) {
+      return null;
+    }
+    String suffix = "ns";
+    if (ns >= 1000.0) {
+      ns /= 1000.0;
+      suffix = "us";
+    }
+    if (ns >= 1000.0) {
+      ns /= 1000.0;
+      suffix = "ms";
+    }
+    if (ns >= 1000.0) {
+      ns /= 1000.0;
+      suffix = "s";
+    }
+    return String.format("%4.1f%s", ns, suffix).trim();
+  }
+
+  public static class EntriesInfo {
+    public Long mem;
+    public Long disk;
+    public String space;
+
+    public void setMem(long mem) {
+      this.mem = mem != 0 ? mem : null;
+    }
+
+    public void setDisk(long disk) {
+      this.disk = disk != 0 ? disk : null;
+    }
+
+    public void setSpace(double value) {
+      space = bytes(value);
+    }
+
+    private static String bytes(double value) {
+      value /= 1024;
+      String suffix = "k";
+
+      if (value > 1024) {
+        value /= 1024;
+        suffix = "m";
+      }
+      if (value > 1024) {
+        value /= 1024;
+        suffix = "g";
+      }
+      return String.format("%1$6.2f%2$s", value, suffix).trim();
+    }
+  }
+
+  public static class HitRatioInfo {
+    public Integer mem;
+    public Integer disk;
+
+    public void setMem(long value, long total) {
+      mem = percent(value, total);
+    }
+
+    public void setDisk(long value, long total) {
+      disk = percent(value, total);
+    }
+
+    private static Integer percent(long value, long total) {
+      if (total <= 0) {
+        return null;
+      }
+      return (int) ((100 * value) / total);
+    }
+  }
+
+  public enum CacheType {
+    MEM,
+    DISK
+  }
+}