using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Text;
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using MemoryProfilerWindow;
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using UnityEditor.MemoryProfiler;
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using UnityEngine;
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namespace MemoryProfilerWindow
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{
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class ShortestPathToRootFinder
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{
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private readonly CrawledMemorySnapshot _snapshot;
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public ShortestPathToRootFinder(CrawledMemorySnapshot snapshot)
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{
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_snapshot = snapshot;
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}
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public ThingInMemory[] FindFor(ThingInMemory thing)
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{
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var seen = new HashSet<ThingInMemory>();
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var queue = new Queue<List<ThingInMemory>>();
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queue.Enqueue(new List<ThingInMemory> { thing});
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while (queue.Any())
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{
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var pop = queue.Dequeue();
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var tip = pop.Last();
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string reason;
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if (IsRoot(tip, out reason))
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return pop.ToArray();
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foreach (var next in tip.referencedBy)
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{
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if (seen.Contains(next))
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continue;
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seen.Add(next);
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var dupe = new List<ThingInMemory>(pop) {next};
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queue.Enqueue(dupe);
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}
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}
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return null;
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}
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public bool IsRoot(ThingInMemory thing, out string reason)
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{
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reason = null;
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if (thing is StaticFields)
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{
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reason = "Static fields are global variables. Anything they reference will not be unloaded.";
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return true;
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}
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if (thing is ManagedObject)
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return false;
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if (thing is GCHandle)
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return false;
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var nativeObject = thing as NativeUnityEngineObject;
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if (nativeObject == null)
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throw new ArgumentException("Unknown type: " + thing.GetType());
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if (nativeObject.isManager)
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{
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reason = "this is an internal unity'manager' style object, which is a global object that will never be unloaded";
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return true;
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}
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if (nativeObject.isDontDestroyOnLoad)
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{
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reason = "DontDestroyOnLoad() was called on this object, so it will never be unloaded";
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return true;
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}
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if ((nativeObject.hideFlags & HideFlags.DontUnloadUnusedAsset) != 0)
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{
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reason = "the DontUnloadUnusedAsset hideflag is set on this object. Unity's builtin resources set this flag. Users can also set the flag themselves";
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return true;
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}
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if (nativeObject.isPersistent)
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return false;
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if (IsComponent(nativeObject.classID))
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{
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reason = "this is a component, living on a gameobject, that is either part of the loaded scene, or was generated by script. It will be unloaded on next scene load.";
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return true;
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}
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if (IsGameObject(nativeObject.classID))
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{
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reason = "this is a gameobject, that is either part of the loaded scene, or was generated by script. It will be unloaded on next scene load if nobody is referencing it";
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return true;
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}
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if (IsAssetBundle(nativeObject.classID))
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{
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reason = "this object is an assetbundle, which is never unloaded automatically, but only through an explicit .Unload() call.";
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return true;
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}
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reason = "This object is a root, but the memory profiler UI does not yet understand why";
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return true;
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}
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private bool IsGameObject(int classID)
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{
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return _snapshot.nativeTypes[classID].name == "GameObject";
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}
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private bool IsAssetBundle(int classID)
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{
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return _snapshot.nativeTypes[classID].name == "AssetBundle";
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}
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private bool IsComponent(int classID)
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{
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var packedNativeType = _snapshot.nativeTypes[classID];
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if (packedNativeType.name == "Component")
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return true;
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#if UNITY_5_6_OR_NEWER
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var baseClassID = packedNativeType.nativeBaseTypeArrayIndex;
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#else
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var baseClassID = packedNativeType.baseClassId;
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#endif
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return baseClassID != -1 && IsComponent(baseClassID);
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}
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}
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}
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