[rygel] Avoid always re-reading all mime-types on startup

[Jens Georg <jensgeorg src gnome org>]

commit d2a2b925ae67307a8b96c1dead05609f87258e04
Author: Matteo Settenvini <matteo member fsf org>
Date:   Thu Feb 16 12:27:50 2017 -0300

    Avoid always re-reading all mime-types on startup
    
    This commits optimizes startup time, when scanning directories with
    many files which are already cached and up-to-date. Before, we were
    always opening and reading from them to determine their mime-type,
    even though it was already in the local database. Now we re-use
    this information, getting a speed up which can be even of
    several minutes, especially on systems with rotational drives.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778778

 .../media-export/rygel-media-export-extractor.vala |   11 ++--
 .../media-export/rygel-media-export-harvester.vala |    2 +-
 .../rygel-media-export-harvesting-task.vala        |   65 +++++++++++---------
 .../rygel-media-export-media-cache.vala            |    9 ++-
 .../rygel-media-export-sql-factory.vala            |    2 +-
 5 files changed, 51 insertions(+), 38 deletions(-)
---
diff --git a/src/plugins/media-export/rygel-media-export-extractor.vala 
b/src/plugins/media-export/rygel-media-export-extractor.vala
index 2fd9346..3625469 100644
--- a/src/plugins/media-export/rygel-media-export-extractor.vala
+++ b/src/plugins/media-export/rygel-media-export-extractor.vala
@@ -91,12 +91,11 @@ public class Rygel.MediaExport.Extractor : Object {
 
     public virtual async void run () throws Error {
         var file_info = yield file.query_info_async (FileAttribute.STANDARD_TYPE + "," +
-                                                     FileAttribute.STANDARD_CONTENT_TYPE
-                                                 + "," +
-                                                 FileAttribute.STANDARD_SIZE + "," +
-                                                 FileAttribute.TIME_MODIFIED + "," +
-                                                 FileAttribute.STANDARD_DISPLAY_NAME,
-                                                 FileQueryInfoFlags.NONE);
+                                                     FileAttribute.STANDARD_CONTENT_TYPE + "," +
+                                                     FileAttribute.STANDARD_SIZE + "," +
+                                                     FileAttribute.TIME_MODIFIED + "," +
+                                                     FileAttribute.STANDARD_DISPLAY_NAME,
+                                                     FileQueryInfoFlags.NONE);
         var display_name = file_info.get_display_name ();
         var title = this.strip_invalid_entities (display_name);
         this.serialized_info.insert (Serializer.TITLE, "s", title);
diff --git a/src/plugins/media-export/rygel-media-export-harvester.vala 
b/src/plugins/media-export/rygel-media-export-harvester.vala
index d72c7de..0d47032 100644
--- a/src/plugins/media-export/rygel-media-export-harvester.vala
+++ b/src/plugins/media-export/rygel-media-export-harvester.vala
@@ -80,7 +80,7 @@ internal class Rygel.MediaExport.Harvester : GLib.Object {
         var is_blacklisted = cache.is_blacklisted (file);
 
         if (is_blacklisted) {
-            debug ("URI %s is not eligble due to blacklising",
+            debug ("URI %s is not eligible due to blacklisting",
                    file.get_uri ());
         }
 
diff --git a/src/plugins/media-export/rygel-media-export-harvesting-task.vala 
b/src/plugins/media-export/rygel-media-export-harvesting-task.vala
index 2023e58..a3f9227 100644
--- a/src/plugins/media-export/rygel-media-export-harvesting-task.vala
+++ b/src/plugins/media-export/rygel-media-export-harvesting-task.vala
@@ -51,11 +51,13 @@ public class Rygel.MediaExport.HarvestingTask : Rygel.StateMachine,
     private const string HARVESTER_ATTRIBUTES =
                                         FileAttribute.STANDARD_NAME + "," +
                                         FileAttribute.STANDARD_TYPE + "," +
-                                        FileAttribute.TIME_MODIFIED + "," +
-                                        FileAttribute.STANDARD_CONTENT_TYPE + "," +
                                         FileAttribute.STANDARD_SIZE + "," +
+                                        FileAttribute.TIME_MODIFIED + "," +
                                         FileAttribute.STANDARD_IS_HIDDEN;
 
+    private const string HARVESTER_MIME_TYPE_ATTRIBUTES =
+                                        FileAttribute.STANDARD_CONTENT_TYPE;
+
     public HarvestingTask (RecursiveFileMonitor monitor,
                            File                 file,
                            MediaContainer       parent) {
@@ -142,35 +144,49 @@ public class Rygel.MediaExport.HarvestingTask : Rygel.StateMachine,
      *   - The current mtime of the file is larger than the cached
      *   - The size has changed
      * @param file to check
-     * @param info FileInfo of the file to check
+     * @param info FileInfo of the file to check, containing at
+     *             least size, mtime and type (but not necessarily
+     *             mime type)
      * @return true, if the file has been queued, false otherwise.
      */
     private bool push_if_changed_or_unknown (File       file,
                                              FileInfo   info) {
-        int64 timestamp;
-        int64 size;
         try {
-            if (this.cache.exists (file, out timestamp, out size)) {
+            int64 timestamp;
+            int64 size;
+            string mime_type;
+
+            bool is_cached = this.cache.exists (file, out timestamp, out size, out mime_type);
+            if (is_cached) {
                 int64 mtime = (int64) info.get_attribute_uint64
                                         (FileAttribute.TIME_MODIFIED);
+                if (mtime <= timestamp &&
+                    info.get_size () == size) {
+                    return false;
+                }
 
-                if (mtime > timestamp ||
-                    info.get_size () != size) {
-                    var entry = new FileQueueEntry (file,
-                                                    true,
-                                                    info.get_content_type ());
-                    this.files.offer (entry);
+                info.set_content_type(mime_type);
+            }
 
-                    return true;
-                }
-            } else {
-                var entry = new FileQueueEntry (file,
-                                                false,
-                                                info.get_content_type ());
-                this.files.offer (entry);
+            if (info.get_content_type () == null) {
+                var extended_info = file.query_info
+                                        (HARVESTER_MIME_TYPE_ATTRIBUTES,
+                                         FileQueryInfoFlags.NONE);
+                info.set_content_type (extended_info.get_content_type ());
+            }
 
-                return true;
+            // Check if the file needs to be harvested at all either because
+            // it is denied by filter or it hasn't updated
+            if (!Harvester.is_eligible (file, info)) {
+                return false;
             }
+
+            var entry = new FileQueueEntry (file,
+                                            is_cached,
+                                            info.get_content_type ());
+            this.files.offer (entry);
+
+            return true;
         } catch (Error error) {
             warning (_("Failed to query database: %s"), error.message);
         }
@@ -185,7 +201,6 @@ public class Rygel.MediaExport.HarvestingTask : Rygel.StateMachine,
             return false;
         }
 
-
         if (info.get_file_type () == FileType.DIRECTORY) {
             // Check if we have an "exploded" DVD structure
             if (file.get_child ("VIDEO_TS").query_exists ()) {
@@ -211,13 +226,7 @@ public class Rygel.MediaExport.HarvestingTask : Rygel.StateMachine,
 
             return true;
         } else {
-            // Check if the file needs to be harvested at all either because
-            // it is denied by filter or it hasn't updated
-            if (Harvester.is_eligible (file, info)) {
-                return this.push_if_changed_or_unknown (file, info);
-            }
-
-            return false;
+            return this.push_if_changed_or_unknown (file, info);
         }
     }
 
diff --git a/src/plugins/media-export/rygel-media-export-media-cache.vala 
b/src/plugins/media-export/rygel-media-export-media-cache.vala
index 74bbdf1..272e21d 100644
--- a/src/plugins/media-export/rygel-media-export-media-cache.vala
+++ b/src/plugins/media-export/rygel-media-export-media-cache.vala
@@ -44,6 +44,7 @@ internal enum Rygel.MediaExport.ObjectType {
 internal struct Rygel.MediaExport.ExistsCacheEntry {
     int64 mtime;
     int64 size;
+    string content_type;
 }
 
 /**
@@ -219,15 +220,18 @@ public class Rygel.MediaExport.MediaCache : Object {
 
     public bool exists (File      file,
                         out int64 timestamp,
-                        out int64 size) throws DatabaseError {
+                        out int64 size,
+                        out string mime_type) throws DatabaseError {
         var uri = file.get_uri ();
         GLib.Value[] values = { uri };
+        mime_type = null;
 
         if (this.exists_cache.has_key (uri)) {
             var entry = this.exists_cache.get (uri);
             this.exists_cache.unset (uri);
             timestamp = entry.mtime;
             size = entry.size;
+            mime_type = entry.content_type;
 
             return true;
         }
@@ -634,7 +638,8 @@ public class Rygel.MediaExport.MediaCache : Object {
             var entry = ExistsCacheEntry ();
             entry.mtime = statement.column_int64 (1);
             entry.size = statement.column_int64 (0);
-            this.exists_cache.set (statement.column_text (2), entry);
+            entry.content_type = statement.column_text (2);
+            this.exists_cache.set (statement.column_text (3), entry);
         }
     }
 
diff --git a/src/plugins/media-export/rygel-media-export-sql-factory.vala 
b/src/plugins/media-export/rygel-media-export-sql-factory.vala
index 298f01b..8d4ee4e 100644
--- a/src/plugins/media-export/rygel-media-export-sql-factory.vala
+++ b/src/plugins/media-export/rygel-media-export-sql-factory.vala
@@ -305,7 +305,7 @@ internal class Rygel.MediaExport.SQLFactory : Object {
     "CREATE INDEX IF NOT EXISTS idx_blacklist on blacklist(uri);";
 
     private const string EXISTS_CACHE_STRING =
-    "SELECT m.size, o.timestamp, o.uri FROM Object o " +
+    "SELECT m.size, o.timestamp, m.mime_type, o.uri FROM Object o " +
         "JOIN meta_data m ON o.upnp_id = m.object_fk";
 
     private const string STATISTICS_STRING =