MediaScanner: Add support for scanning empty directories

Currently the media scanner does not create database entries for directories
unless they contain a file that is scanned.
Fixing this so we provide a consistent view of the world to MTP.

Change-Id: Ia776acfeae23192183e7192d63cdc34d830ea889
Signed-off-by: Mike Lockwood <lockwood@android.com>

4 files changed, 79 insertions, 66 deletions

diff --git a/media/java/android/media/MediaScanner.java b/media/java/android/media/MediaScanner.java
index 63ec6b2..365fd65 100644
--- a/media/java/android/media/MediaScanner.java
+++ b/media/java/android/media/MediaScanner.java
@@ -407,55 +407,60 @@ public class MediaScanner
         private long mFileSize;
         private String mWriter;
 
-        public FileCacheEntry beginFile(String path, String mimeType, long lastModified, long fileSize) {
-
-            // special case certain file names
-            // I use regionMatches() instead of substring() below
-            // to avoid memory allocation
-            int lastSlash = path.lastIndexOf('/');
-            if (lastSlash >= 0 && lastSlash + 2 < path.length()) {
-                // ignore those ._* files created by MacOS
-                if (path.regionMatches(lastSlash + 1, "._", 0, 2)) {
-                    return null;
-                }
+        public FileCacheEntry beginFile(String path, String mimeType, long lastModified,
+                long fileSize, boolean isDirectory) {
+            mMimeType = mimeType;
+            mFileType = 0;
+            mFileSize = fileSize;
 
-                // ignore album art files created by Windows Media Player:
-                // Folder.jpg, AlbumArtSmall.jpg, AlbumArt_{...}_Large.jpg and AlbumArt_{...}_Small.jpg
-                if (path.regionMatches(true, path.length() - 4, ".jpg", 0, 4)) {
-                    if (path.regionMatches(true, lastSlash + 1, "AlbumArt_{", 0, 10) ||
-                            path.regionMatches(true, lastSlash + 1, "AlbumArt.", 0, 9)) {
+            if (!isDirectory) {
+                // special case certain file names
+                // I use regionMatches() instead of substring() below
+                // to avoid memory allocation
+                int lastSlash = path.lastIndexOf('/');
+                if (lastSlash >= 0 && lastSlash + 2 < path.length()) {
+                    // ignore those ._* files created by MacOS
+                    if (path.regionMatches(lastSlash + 1, "._", 0, 2)) {
                         return null;
                     }
-                    int length = path.length() - lastSlash - 1;
-                    if ((length == 17 && path.regionMatches(true, lastSlash + 1, "AlbumArtSmall", 0, 13)) ||
-                            (length == 10 && path.regionMatches(true, lastSlash + 1, "Folder", 0, 6))) {
-                        return null;
+
+                    // ignore album art files created by Windows Media Player:
+                    // Folder.jpg, AlbumArtSmall.jpg, AlbumArt_{...}_Large.jpg
+                    // and AlbumArt_{...}_Small.jpg
+                    if (path.regionMatches(true, path.length() - 4, ".jpg", 0, 4)) {
+                        if (path.regionMatches(true, lastSlash + 1, "AlbumArt_{", 0, 10) ||
+                                path.regionMatches(true, lastSlash + 1, "AlbumArt.", 0, 9)) {
+                            return null;
+                        }
+                        int length = path.length() - lastSlash - 1;
+                        if ((length == 17 && path.regionMatches(
+                                true, lastSlash + 1, "AlbumArtSmall", 0, 13)) ||
+                                (length == 10
+                                 && path.regionMatches(true, lastSlash + 1, "Folder", 0, 6))) {
+                            return null;
+                        }
                     }
                 }
-            }
 
-            mMimeType = mimeType;
-            mFileType = 0;
-            mFileSize = fileSize;
-
-            // try mimeType first, if it is specified
-            if (mimeType != null) {
-                mFileType = MediaFile.getFileTypeForMimeType(mimeType);
-            }
+                // try mimeType first, if it is specified
+                if (mimeType != null) {
+                    mFileType = MediaFile.getFileTypeForMimeType(mimeType);
+                }
 
-            // if mimeType was not specified, compute file type based on file extension.
-            if (mFileType == 0) {
-                MediaFile.MediaFileType mediaFileType = MediaFile.getFileType(path);
-                if (mediaFileType != null) {
-                    mFileType = mediaFileType.fileType;
-                    if (mMimeType == null) {
-                        mMimeType = mediaFileType.mimeType;
+                // if mimeType was not specified, compute file type based on file extension.
+                if (mFileType == 0) {
+                    MediaFile.MediaFileType mediaFileType = MediaFile.getFileType(path);
+                    if (mediaFileType != null) {
+                        mFileType = mediaFileType.fileType;
+                        if (mMimeType == null) {
+                            mMimeType = mediaFileType.mimeType;
+                        }
                     }
                 }
-            }
 
-            if (isDrmEnabled() && MediaFile.isDrmFileType(mFileType)) {
-                mFileType = getFileTypeFromDrm(path);
+                if (isDrmEnabled() && MediaFile.isDrmFileType(mFileType)) {
+                    mFileType = getFileTypeFromDrm(path);
+                }
             }
 
             String key = path;
@@ -470,7 +475,9 @@ public class MediaScanner
             FileCacheEntry entry = mFileCache.get(key);
             if (entry == null) {
                 Uri tableUri;
-                if (MediaFile.isVideoFileType(mFileType)) {
+                if (isDirectory) {
+                    tableUri = mFilesUri;
+                } else if (MediaFile.isVideoFileType(mFileType)) {
                     tableUri = mVideoUri;
                 } else if (MediaFile.isImageFileType(mFileType)) {
                     tableUri = mImagesUri;
@@ -479,7 +486,8 @@ public class MediaScanner
                 } else {
                     tableUri = mFilesUri;
                 }
-                entry = new FileCacheEntry(tableUri, 0, path, 0, 0);
+                entry = new FileCacheEntry(tableUri, 0, path, 0,
+                        (isDirectory ? MtpConstants.FORMAT_ASSOCIATION : 0));
                 mFileCache.put(key, entry);
             }
             entry.mSeenInFileSystem = true;
@@ -514,22 +522,19 @@ public class MediaScanner
             return entry;
         }
 
-        public void scanFile(String path, long lastModified, long fileSize) {
+        public void scanFile(String path, long lastModified, long fileSize, boolean isDirectory) {
             // This is the callback funtion from native codes.
             // Log.v(TAG, "scanFile: "+path);
-            doScanFile(path, null, lastModified, fileSize, false);
-        }
-
-        public void scanFile(String path, String mimeType, long lastModified, long fileSize) {
-            doScanFile(path, mimeType, lastModified, fileSize, false);
+            doScanFile(path, null, lastModified, fileSize, isDirectory, false);
         }
 
         public Uri doScanFile(String path, String mimeType, long lastModified,
-                long fileSize, boolean scanAlways) {
+                long fileSize, boolean isDirectory, boolean scanAlways) {
             Uri result = null;
 //            long t1 = System.currentTimeMillis();
             try {
-                FileCacheEntry entry = beginFile(path, mimeType, lastModified, fileSize);
+                FileCacheEntry entry = beginFile(path, mimeType, lastModified,
+                        fileSize, isDirectory);
                 // rescan for metadata if file was modified since last scan
                 if (entry != null && (entry.mLastModifiedChanged || scanAlways)) {
                     String lowpath = path.toLowerCase();
@@ -775,7 +780,11 @@ public class MediaScanner
                     values.put(MediaStore.MediaColumns.MEDIA_SCANNER_NEW_OBJECT_ID, mMtpObjectHandle);
                 }
                 if (tableUri == mFilesUri) {
-                    values.put(Files.FileColumns.FORMAT, MediaFile.getFormatCode(entry.mPath, mMimeType));
+                    int format = entry.mFormat;
+                    if (format == 0) {
+                        format = MediaFile.getFormatCode(entry.mPath, mMimeType);
+                    }
+                    values.put(Files.FileColumns.FORMAT, format);
                 }
                 // new file, insert it
                 result = mMediaProvider.insert(tableUri, values);
@@ -1060,8 +1069,7 @@ public class MediaScanner
             boolean fileMissing = false;
 
             if (!entry.mSeenInFileSystem && !MtpConstants.isAbstractObject(entry.mFormat)) {
-                if (entry.mFormat != MtpConstants.FORMAT_ASSOCIATION &&
-                        inScanDirectory(path, directories)) {
+                if (inScanDirectory(path, directories)) {
                     // we didn't see this file in the scan directory.
                     fileMissing = true;
                 } else {
@@ -1180,7 +1188,7 @@ public class MediaScanner
             long lastModifiedSeconds = file.lastModified() / 1000;
 
             // always scan the file, so we can return the content://media Uri for existing files
-            return mClient.doScanFile(path, mimeType, lastModifiedSeconds, file.length(), true);
+            return mClient.doScanFile(path, mimeType, lastModifiedSeconds, file.length(),false, true);
         } catch (RemoteException e) {
             Log.e(TAG, "RemoteException in MediaScanner.scanFile()", e);
             return null;
@@ -1227,7 +1235,8 @@ public class MediaScanner
                 long lastModifiedSeconds = file.lastModified() / 1000;
 
                 // always scan the file, so we can return the content://media Uri for existing files
-                mClient.doScanFile(path, mediaFileType.mimeType, lastModifiedSeconds, file.length(), true);
+                mClient.doScanFile(path, mediaFileType.mimeType, lastModifiedSeconds, file.length(),
+                    (format == MtpConstants.FORMAT_ASSOCIATION), true);
             }
         } catch (RemoteException e) {
             Log.e(TAG, "RemoteException in MediaScanner.scanFile()", e);
diff --git a/media/java/android/media/MediaScannerClient.java b/media/java/android/media/MediaScannerClient.java
index 258c3b4..ac326ef 100644
--- a/media/java/android/media/MediaScannerClient.java
+++ b/media/java/android/media/MediaScannerClient.java
@@ -21,9 +21,7 @@ package android.media;
  */
 public interface MediaScannerClient
 {    
-    public void scanFile(String path, long lastModified, long fileSize);
-    
-    public void scanFile(String path, String mimeType, long lastModified, long fileSize);
+    public void scanFile(String path, long lastModified, long fileSize, boolean isDirectory);
 
     public void addNoMediaFolder(String path);
 
diff --git a/media/jni/android_media_MediaScanner.cpp b/media/jni/android_media_MediaScanner.cpp
index fd0b233..a5176fa 100644
--- a/media/jni/android_media_MediaScanner.cpp
+++ b/media/jni/android_media_MediaScanner.cpp
@@ -62,7 +62,7 @@ public:
         }
         else {
             mScanFileMethodID = env->GetMethodID(mediaScannerClientInterface, "scanFile",
-                                                     "(Ljava/lang/String;JJ)V");
+                                                     "(Ljava/lang/String;JJZ)V");
             mHandleStringTagMethodID = env->GetMethodID(mediaScannerClientInterface, "handleStringTag",
                                                      "(Ljava/lang/String;Ljava/lang/String;)V");
             mSetMimeTypeMethodID = env->GetMethodID(mediaScannerClientInterface, "setMimeType",
@@ -78,12 +78,14 @@ public:
     }
     
     // returns true if it succeeded, false if an exception occured in the Java code
-    virtual bool scanFile(const char* path, long long lastModified, long long fileSize)
+    virtual bool scanFile(const char* path, long long lastModified,
+            long long fileSize, bool isDirectory)
     {
         jstring pathStr;
         if ((pathStr = mEnv->NewStringUTF(path)) == NULL) return false;
 
-        mEnv->CallVoidMethod(mClient, mScanFileMethodID, pathStr, lastModified, fileSize);
+        mEnv->CallVoidMethod(mClient, mScanFileMethodID, pathStr, lastModified,
+                fileSize, isDirectory);
 
         mEnv->DeleteLocalRef(pathStr);
         return (!mEnv->ExceptionCheck());
diff --git a/media/libmedia/MediaScanner.cpp b/media/libmedia/MediaScanner.cpp
index c31b622..5ec573e 100644
--- a/media/libmedia/MediaScanner.cpp
+++ b/media/libmedia/MediaScanner.cpp
@@ -84,6 +84,7 @@ status_t MediaScanner::doProcessDirectory(
     // place to copy file or directory name
     char* fileSpot = path + strlen(path);
     struct dirent* entry;
+    struct stat statbuf;
 
     // ignore directories that contain a  ".nomedia" file
     if (pathRemaining >= 8 /* strlen(".nomedia") */ ) {
@@ -125,7 +126,6 @@ status_t MediaScanner::doProcessDirectory(
             // If the type is unknown, stat() the file instead.
             // This is sometimes necessary when accessing NFS mounted filesystems, but
             // could be needed in other cases well.
-            struct stat statbuf;
             if (stat(path, &statbuf) == 0) {
                 if (S_ISREG(statbuf.st_mode)) {
                     type = DT_REG;
@@ -142,8 +142,15 @@ status_t MediaScanner::doProcessDirectory(
                 // for example, the Mac ".Trashes" directory
                 if (name[0] == '.') continue;
 
+                // report the directory to the client
+                if (stat(path, &statbuf) == 0) {
+                    client.scanFile(path, statbuf.st_mtime, 0, true);
+                }
+
+                // and now process its contents
                 strcat(fileSpot, "/");
-                int err = doProcessDirectory(path, pathRemaining - nameLength - 1, client, exceptionCheck, exceptionEnv);
+                int err = doProcessDirectory(path, pathRemaining - nameLength - 1, client,
+                        exceptionCheck, exceptionEnv);
                 if (err) {
                     // pass exceptions up - ignore other errors
                     if (exceptionCheck && exceptionCheck(exceptionEnv)) goto failure;
@@ -151,11 +158,8 @@ status_t MediaScanner::doProcessDirectory(
                     continue;
                 }
             } else {
-                struct stat statbuf;
                 stat(path, &statbuf);
-                if (statbuf.st_size > 0) {
-                    client.scanFile(path, statbuf.st_mtime, statbuf.st_size);
-                }
+                client.scanFile(path, statbuf.st_mtime, statbuf.st_size, false);
                 if (exceptionCheck && exceptionCheck(exceptionEnv)) goto failure;
             }
         }