[Fix] Issue #1 修复了ImageCache对重复缓存请求的策略(忽略并返回)导致的后续处理发生NPE的问题;

[Update] ImageCache 更新了ImageCache, 将该部分单独分离到 ImageCacheStore;
[Update] BotCommandProcess 适配新的ImageCache, 调整内容检查的时机以减少不必要的API访问;

src/main/java/net/lamgc/cgj/bot/BotCommandProcess.java

@@ -2,7 +2,6 @@ package net.lamgc.cgj.bot;
 
 import com.google.common.base.Strings;
 import com.google.common.base.Throwables;
-import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import com.google.gson.*;
 import io.netty.handler.codec.http.HttpHeaderNames;
 import net.lamgc.cgj.Main;
@@ -15,7 +14,6 @@ import net.lamgc.cgj.pixiv.PixivURL;
 import net.lamgc.cgj.util.URLs;
 import net.lamgc.utils.base.runner.Argument;
 import net.lamgc.utils.base.runner.Command;
-import net.lamgc.utils.event.EventExecutor;
 import net.lz1998.cq.utils.CQCode;
 import org.apache.http.HttpResponse;
 import org.apache.http.client.methods.HttpGet;
@@ -29,9 +27,6 @@ import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.text.SimpleDateFormat;
 import java.util.*;
-import java.util.concurrent.LinkedBlockingQueue;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 
 @SuppressWarnings({"SynchronizationOnLocalVariableOrMethodParameter", "SameParameterValue"})
@@ -56,20 +51,6 @@ public class BotCommandProcess {
     private final static CacheStore<List<String>> pagesCache = new StringListRedisCacheStore(BotEventHandler.redisServer, "imagePages");
     public final static CacheStore<JsonElement> reportStore = new JsonRedisCacheStore(BotEventHandler.redisServer, "report", gson);
 
-    /**
-     * 图片异步缓存执行器
-     */
-    private final static EventExecutor imageCacheExecutor = new EventExecutor(new ThreadPoolExecutor(
-            Runtime.getRuntime().availableProcessors() >= 2 ? 2 : 1,
-            (int) Math.ceil(Runtime.getRuntime().availableProcessors() / 2F),
-            5L, TimeUnit.SECONDS,
-            new LinkedBlockingQueue<>(128),
-            new ThreadFactoryBuilder()
-                    .setNameFormat("imageCacheThread-%d")
-                    .build(),
-            new ThreadPoolExecutor.DiscardOldestPolicy()
-    ));
-
     private final static RankingUpdateTimer updateTimer = new RankingUpdateTimer();
 
     public static void initialize() {
@@ -77,12 +58,6 @@ public class BotCommandProcess {
 
         SettingProperties.loadProperties();
 
-        try {
-            imageCacheExecutor.addHandler(new ImageCacheHandler());
-        } catch (IllegalAccessException e) {
-            e.printStackTrace();
-        }
-
         updateTimer.schedule(null);
         log.info("初始化完成.");
     }
@@ -544,6 +519,20 @@ public class BotCommandProcess {
             @Argument(name = "quality", force = false) PixivDownload.PageQuality quality,
             @Argument(name = "page", force = false, defaultValue = "1") int pageIndex) {
         log.debug("IllustId: {}, Quality: {}, PageIndex: {}", illustId, quality.name(), pageIndex);
+
+        try {
+            if (isNoSafe(illustId, SettingProperties.getProperties(fromGroup), false)) {
+                log.warn("作品 {} 存在R-18内容且设置\"image.allowR18\"为false，将屏蔽该作品不发送.", illustId);
+                return "（根据设置，该作品已被屏蔽！）";
+            } else if(isReported(illustId)) {
+                log.warn("作品Id {} 被报告, 正在等待审核, 跳过该作品.", illustId);
+                return "（该作品已被封印）";
+            }
+        } catch (IOException e) {
+            log.warn("作品信息无法获取!", e);
+            return "发生网络异常，无法获取图片！";
+        }
+
         List<String> pagesList;
         try {
             pagesList = getIllustPages(illustId, quality, false);
@@ -564,19 +553,6 @@ public class BotCommandProcess {
             return "指定的页数超出了范围(总共 " + pagesList.size() + " 页)";
         }
 
-        try {
-            if (isNoSafe(illustId, SettingProperties.getProperties(fromGroup), false)) {
-                log.warn("作品 {} 存在R-18内容且设置\"image.allowR18\"为false，将屏蔽该作品不发送.", illustId);
-                return "（根据设置，该作品已被屏蔽！）";
-            } else if(isReported(illustId)) {
-                log.warn("作品Id {} 被报告, 正在等待审核, 跳过该作品.", illustId);
-                return "（该作品已被封印）";
-            }
-        } catch (IOException e) {
-            log.warn("作品信息无法获取!", e);
-            return "发生网络异常，无法获取图片！";
-        }
-
         String downloadLink = pagesList.get(pageIndex - 1);
         String fileName = URLs.getResourceName(Strings.nullToEmpty(downloadLink));
         File imageFile = new File(getImageStoreDir(), downloadLink.substring(downloadLink.lastIndexOf("/") + 1));
@@ -601,12 +577,11 @@ public class BotCommandProcess {
                 }
             }
 
-            ImageCacheObject taskObject = new ImageCacheObject(imageCache, illustId, downloadLink, imageFile);
             try {
-                imageCacheExecutor.executorSync(taskObject);
+                ImageCacheStore.executeCacheRequest(new ImageCacheObject(imageCache, illustId, downloadLink, imageFile));
             } catch (InterruptedException e) {
-                log.error("等待图片下载时发生中断", e);
+                log.warn("图片缓存被中断", e);
-                return "图片获取失败!";
+                return "(错误：图片获取超时)";
             }
         } else {
             log.debug("图片 {} 缓存命中.", fileName);

src/main/java/net/lamgc/cgj/bot/cache/ImageCacheHandler.java

@@ -28,9 +28,9 @@ public class ImageCacheHandler implements EventHandler {
     private final static Set<ImageCacheObject> cacheQueue = Collections.synchronizedSet(new HashSet<>());
 
     @SuppressWarnings("unused")
-    public void getImageToCache(ImageCacheObject event) {
+    public void getImageToCache(ImageCacheObject event) throws Exception {
         if(cacheQueue.contains(event)) {
-            log.debug("图片 {} 已存在相同缓存任务, 跳过.", event.getStoreFile().getName());
+            log.warn("图片 {} 已存在相同缓存任务, 跳过.", event.getStoreFile().getName());
             return;
         } else {
             cacheQueue.add(event);
@@ -43,11 +43,11 @@ public class ImageCacheHandler implements EventHandler {
             try {
                 if(!storeFile.exists() && !storeFile.createNewFile()) {
                     log.error("无法创建文件(Path: {})", storeFile.getAbsolutePath());
-                    return;
+                    throw new IOException("Failed to create file");
                 }
             } catch (IOException e) {
                 log.error("无法创建文件(Path: {})", storeFile.getAbsolutePath());
-                e.printStackTrace();
+                throw e;
             }
 
             HttpGet request = new HttpGet(event.getDownloadLink());
@@ -57,11 +57,11 @@ public class ImageCacheHandler implements EventHandler {
                 response = httpClient.execute(request);
             } catch (IOException e) {
                 log.error("Http请求时发生异常", e);
-                return;
+                throw e;
             }
             if(response.getStatusLine().getStatusCode() != 200) {
                 log.warn("Http请求异常：{}", response.getStatusLine());
-                return;
+                throw new IOException("Http Response Error: " + response.getStatusLine());
             }
 
             log.debug("正在下载...(Content-Length: {}KB)", response.getEntity().getContentLength() / 1024);
@@ -69,7 +69,7 @@ public class ImageCacheHandler implements EventHandler {
                 IOUtils.copy(response.getEntity().getContent(), fos);
             } catch (IOException e) {
                 log.error("下载图片时发生异常", e);
-                return;
+                throw e;
             }
             event.getImageCache().put(URLs.getResourceName(event.getDownloadLink()), storeFile);
         } finally {

src/main/java/net/lamgc/cgj/bot/cache/ImageCacheStore.java

@@ -0,0 +1,109 @@
+package net.lamgc.cgj.bot.cache;
+
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Hashtable;
+import java.util.Map;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+public final class ImageCacheStore {
+
+    private final static Logger log = LoggerFactory.getLogger(ImageCacheStore.class.getName());
+
+    private final static Map<ImageCacheObject, Task> cacheMap = new Hashtable<>();
+
+    private final static ThreadPoolExecutor imageCacheExecutor = new ThreadPoolExecutor(
+            4, 6,
+            30L,
+            TimeUnit.SECONDS,
+            new LinkedBlockingQueue<>(100),
+            new ThreadFactoryBuilder()
+                    .setNameFormat("ImageCacheThread-%d")
+                    .build()
+    );
+
+    private final static ImageCacheHandler handler = new ImageCacheHandler();
+
+    private ImageCacheStore() {}
+
+    /**
+     * 传递图片缓存任务, 并等待缓存完成.
+     * @param cacheObject 缓存任务组
+     */
+    public static void executeCacheRequest(ImageCacheObject cacheObject) throws InterruptedException {
+        Task task = getTaskState(cacheObject);
+        if(task.taskState.get() == TaskState.COMPLETE) {
+            return;
+        }
+
+        boolean locked = false;
+        try {
+            if(task.taskState.get() == TaskState.COMPLETE) {
+                return;
+            }
+            task.lock.lock();
+            locked = true;
+            // 双重检查
+            if(task.taskState.get() == TaskState.COMPLETE) {
+                return;
+            }
+
+            // 置任务状态
+            task.taskState.set(TaskState.RUNNING);
+
+            try {
+                Throwable throwable = imageCacheExecutor.submit(() -> {
+                    try {
+                        handler.getImageToCache(cacheObject);
+                    } catch (Throwable e) {
+                        return e;
+                    }
+                    return null;
+                }).get();
+
+                if(throwable == null) {
+                    task.taskState.set(TaskState.COMPLETE);
+                } else {
+                    task.taskState.set(TaskState.ERROR);
+                }
+            } catch (ExecutionException e) {
+                log.error("执行图片缓存任务时发生异常", e);
+            }
+        } finally {
+            if(locked) {
+                task.lock.unlock();
+            }
+        }
+
+    }
+
+    private static Task getTaskState(ImageCacheObject cacheObject) {
+        if(!cacheMap.containsKey(cacheObject)) {
+            cacheMap.put(cacheObject, new Task());
+        }
+        return cacheMap.get(cacheObject);
+    }
+
+    /**
+     * 任务状态
+     */
+    private enum TaskState {
+        READY, RUNNING, COMPLETE, ERROR
+    }
+
+    private static class Task {
+
+        public final ReentrantLock lock = new ReentrantLock(true);
+
+        public final AtomicReference<TaskState> taskState = new AtomicReference<>(TaskState.READY);
+
+        public final Condition condition = lock.newCondition();
+
+    }
+
+}