am c0a8b2cf: Merge "Implement checks before performing background attachment download" into honeycomb

* commit 'c0a8b2cfb05f91e6f18c587a2698b9f8c226ba55':
  Implement checks before performing background attachment download

src/com/android/email/AttachmentInfo.java

@@ -24,6 +24,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
+import android.database.Cursor;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 import android.net.Uri;
@@ -37,18 +38,41 @@ import java.util.List;
  * based on the attachment's filename and mime type.
  */
 public class AttachmentInfo {
+    // Projection which can be used with the constructor taking a Cursor argument
+    public static final String[] PROJECTION = new String[] {Attachment.RECORD_ID, Attachment.SIZE,
+        Attachment.FILENAME, Attachment.MIME_TYPE, Attachment.ACCOUNT_KEY};
+    // Offsets into PROJECTION
+    public static final int COLUMN_ID = 0;
+    public static final int COLUMN_SIZE = 1;
+    public static final int COLUMN_FILENAME = 2;
+    public static final int COLUMN_MIME_TYPE = 3;
+    public static final int COLUMN_ACCOUNT_KEY = 4;
+
+    public final long mId;
+    public final long mSize;
     public final String mName;
     public final String mContentType;
-    public final long mSize;
+    public final long mAccountKey;
-    public final long mId;
     public final boolean mAllowView;
     public final boolean mAllowSave;
 
     public AttachmentInfo(Context context, Attachment attachment) {
-        mSize = attachment.mSize;
+        this(context, attachment.mId, attachment.mSize, attachment.mFileName, attachment.mMimeType,
-        mContentType = AttachmentProvider.inferMimeType(attachment.mFileName, attachment.mMimeType);
+                attachment.mAccountKey);
-        mName = attachment.mFileName;
+    }
-        mId = attachment.mId;
+
+    public AttachmentInfo(Context context, Cursor c) {
+        this(context, c.getLong(COLUMN_ID), c.getLong(COLUMN_SIZE), c.getString(COLUMN_FILENAME),
+                c.getString(COLUMN_MIME_TYPE), c.getLong(COLUMN_ACCOUNT_KEY));
+    }
+
+    public AttachmentInfo(Context context, long id, long size, String fileName, String mimeType,
+            long accountKey) {
+        mSize = size;
+        mContentType = AttachmentProvider.inferMimeType(fileName, mimeType);
+        mName = fileName;
+        mId = id;
+        mAccountKey = accountKey;
         boolean canView = true;
         boolean canSave = true;
 
@@ -121,7 +145,11 @@ public class AttachmentInfo {
      * An attachment is eligible for download if it can either be viewed or saved (or both)
      * @return whether the attachment is eligible for download
      */
-    public boolean eligibleForDownload() {
+    public boolean isEligibleForDownload() {
         return mAllowView || mAllowSave;
     }
+
+    public String toString() {
+        return "{Attachment " + mId + ":" + mName + "," + mContentType + "," + mSize + "}";
+    }
 }

src/com/android/email/service/AttachmentDownloadService.java

@@ -16,12 +16,13 @@
 
 package com.android.email.service;
 
+import com.android.email.AttachmentInfo;
+import com.android.email.Controller.ControllerService;
 import com.android.email.Email;
+import com.android.email.ExchangeUtils.NullEmailService;
 import com.android.email.NotificationController;
 import com.android.email.Preferences;
 import com.android.email.Utility;
-import com.android.email.Controller.ControllerService;
-import com.android.email.ExchangeUtils.NullEmailService;
 import com.android.email.provider.AttachmentProvider;
 import com.android.email.provider.EmailContent;
 import com.android.email.provider.EmailContent.Account;
@@ -83,9 +84,8 @@ public class AttachmentDownloadService extends Service implements Runnable {
     // Limit on the number of simultaneous downloads per account
     // Note that a limit of 1 is currently enforced by both Services (MailService and Controller)
     private static final int MAX_SIMULTANEOUS_DOWNLOADS_PER_ACCOUNT = 1;
-
+    // Limit on the number of attachments we'll check for background download
-    private static final Uri SINGLE_ATTACHMENT_URI =
+    private static final int MAX_ATTACHMENTS_TO_CHECK = 25;
-        EmailContent.uriWithLimit(Attachment.CONTENT_URI, 1);
 
     /*package*/ static AttachmentDownloadService sRunningService = null;
 
@@ -319,45 +319,44 @@ public class AttachmentDownloadService extends Service implements Runnable {
                 }
             }
 
-            // Respect the user's preference for background downloads
-            if (!mPreferences.getBackgroundAttachments()) {
-                return;
-            }
-
             // Then, try opportunistic download of appropriate attachments
             int backgroundDownloads = MAX_SIMULTANEOUS_DOWNLOADS - mDownloadsInProgress.size();
             // Always leave one slot for user requested download
             if (backgroundDownloads > (MAX_SIMULTANEOUS_DOWNLOADS - 1)) {
-                boolean repeat = true;
+                // We'll load up the newest 25 attachments that aren't loaded or queued
-                while (repeat) {
+                Uri lookupUri = EmailContent.uriWithLimit(Attachment.CONTENT_URI,
-                    // We'll take the most recent unloaded attachment
+                        MAX_ATTACHMENTS_TO_CHECK);
-                    Long prefetchId = Utility.getFirstRowLong(mContext, SINGLE_ATTACHMENT_URI,
+                Cursor c = mContext.getContentResolver().query(lookupUri, AttachmentInfo.PROJECTION,
-                            Attachment.ID_PROJECTION, AttachmentColumns.CONTENT_URI
+                        AttachmentColumns.CONTENT_URI + " isnull AND " + Attachment.FLAGS + "=0",
-                            + " isnull AND " + Attachment.FLAGS + "=0", null,
+                        null, Attachment.RECORD_ID + " DESC");
-                            Attachment.RECORD_ID + " DESC", Attachment.ID_PROJECTION_COLUMN);
+                File cacheDir = mContext.getCacheDir();
-                    if (prefetchId == null) break;
+                try {
-                    if (Email.DEBUG) {
+                    while (c.moveToNext()) {
-                        Log.d(TAG, ">> Prefetch attachment " + prefetchId);
+                        long accountKey = c.getLong(AttachmentInfo.COLUMN_ACCOUNT_KEY);
-                    }
+                        long id = c.getLong(AttachmentInfo.COLUMN_ID);
-                    Attachment att = Attachment.restoreAttachmentWithId(mContext, prefetchId);
+                        if (getServiceClassForAccount(accountKey) == null) {
-                    // If att is null, the attachment must have been deleted out from under us
-                    if (att == null) continue;
-                    if (getServiceClassForAccount(att.mAccountKey) == null) {
                             // Clean up this orphaned attachment; there's no point in keeping it
                             // around; then try to find another one
-                        EmailContent.delete(mContext, Attachment.CONTENT_URI, prefetchId);
+                            EmailContent.delete(mContext, Attachment.CONTENT_URI, id);
-                        continue;
+                        } else if (canPrefetchForAccount(accountKey, cacheDir)) {
-                    }
+                            // Check that the attachment meets system requirements for download
-                    repeat = false;
+                            AttachmentInfo info = new AttachmentInfo(mContext, c);
-                    // TODO It's possible that we're just over limit for this particular account
+                            if (info.isEligibleForDownload()) {
-                    // Handle this so that attachments from other accounts (if any) can be tried
+                                Attachment att = Attachment.restoreAttachmentWithId(mContext, id);
-                    if (canPrefetchForAccount(att.mAccountKey, mContext.getCacheDir())) {
+                                if (att != null) {
+                                    // Start this download and we're done
                                     DownloadRequest req = new DownloadRequest(mContext, att);
                                     mDownloadSet.tryStartDownload(req);
+                                    break;
                                 }
                             }
                         }
                     }
+                } finally {
+                    c.close();
+                }
+            }
+        }
 
         /**
          * Count the number of running downloads in progress for this account
@@ -745,6 +744,12 @@ public class AttachmentDownloadService extends Service implements Runnable {
      * @return true if download is allowed, false otherwise
      */
     /*package*/ boolean canPrefetchForAccount(long accountId, File dir) {
+        Account account = Account.restoreAccountWithId(mContext, accountId);
+        // Check account, just in case
+        if (account == null) return false;
+        // First, check preference and quickly return if prefetch isn't allowed
+        if ((account.mFlags & Account.FLAGS_BACKGROUND_ATTACHMENTS) == 0) return false;
+
         long totalStorage = dir.getTotalSpace();
         long usableStorage = dir.getUsableSpace();
         long minAvailable = (long)(totalStorage * PREFETCH_MINIMUM_STORAGE_AVAILABLE);