FS|RemoteFeed: Remember remote status of cached files

The real last-modified time of remote files is stored in a special
auxiliary file. This ensures that non-versioned files use a version
number that matches the server-side file when Doomsday loads cached
data files.

doomsday/sdk/libcore/include/de/filesys/directoryfeed.h

@@ -105,6 +105,8 @@ class DENG2_PUBLIC DirectoryFeed : public Feed
      */
     static File::Status fileStatus(NativePath const &nativePath);
 
+    static void setFileModifiedTime(NativePath const &nativePath, Time const &modifiedAt);
+
     /**
      * Creates and interprets a single native file and adds it to a folder. The created
      * file is not governed by any feed and will not be pruned during folder pruning.

doomsday/sdk/libcore/src/filesys/directoryfeed.cpp

@@ -27,7 +27,9 @@
 #include <QDir>
 #include <QFileInfo>
 
-using namespace de;
+namespace de {
+
+static String const fileStatusSuffix = ".doomsday_file_status";
 
 DirectoryFeed::DirectoryFeed(NativePath const &nativePath, Flags const &mode)
     : _nativePath(nativePath), _mode(mode) {}
@@ -79,7 +81,10 @@ Feed::PopulatedFiles DirectoryFeed::populate(Folder const &folder)
         }
         else
         {
-            populateFile(folder, entry.fileName(), populated);
+            if (!entry.fileName().endsWith(fileStatusSuffix)) // ignore meta files
+            {
+                populateFile(folder, entry.fileName(), populated);
+            }
         }
     }
     return populated;
@@ -253,17 +258,43 @@ void DirectoryFeed::changeWorkingDir(NativePath const &nativePath)
 File::Status DirectoryFeed::fileStatus(NativePath const &nativePath)
 {
     QFileInfo info(nativePath);
-
     if (!info.exists())
     {
         /// @throw StatusError Determining the file status was not possible.
         throw StatusError("DirectoryFeed::fileStatus", nativePath + " inaccessible");
     }
 
     // Get file status information.
-    return File::Status(info.isDir()? File::Type::Folder : File::Type::File,
-                        dsize(info.size()),
-                        info.lastModified());
+    File::Status st { info.isDir()? File::Type::Folder : File::Type::File,
+                      dsize(info.size()),
+                      info.lastModified() };
+
+    // Check for overridden status.
+    String const overrideName = nativePath + fileStatusSuffix;
+    if (QFileInfo().exists(overrideName))
+    {
+        QFile f(overrideName);
+        if (f.open(QFile::ReadOnly))
+        {
+            st.modifiedAt = Time::fromText(String::fromUtf8(f.readAll()), Time::ISOFormat);
+        }
+    }
+    return st;
+}
+
+void DirectoryFeed::setFileModifiedTime(NativePath const &nativePath, Time const &modifiedAt)
+{
+    String const overrideName = nativePath + fileStatusSuffix;
+    if (!modifiedAt.isValid())
+    {
+        QFile::remove(overrideName);
+        return;
+    }
+    QFile f(overrideName);
+    if (f.open(QFile::WriteOnly | QFile::Truncate))
+    {
+        f.write(modifiedAt.asText(Time::ISOFormat).toUtf8());
+    }
 }
 
 File &DirectoryFeed::manuallyPopulateSingleFile(NativePath const &nativePath,
@@ -314,3 +345,5 @@ File &DirectoryFeed::manuallyPopulateSingleFile(NativePath const &nativePath,
                                             FS::DontInheritFeeds | FS::PopulateNewFolder);
     }
 }
+
+} // namespace de

doomsday/sdk/libcore/src/filesys/remotefile.cpp

@@ -19,11 +19,13 @@
 #include "de/RemoteFile"
 
 #include "de/App"
+#include "de/DirectoryFeed"
 #include "de/FileSystem"
 #include "de/RecordValue"
 #include "de/RemoteFeedRelay"
 #include "de/ScriptSystem"
 #include "de/TextValue"
+#include "de/TimeValue"
 
 namespace de {
 
@@ -35,7 +37,6 @@ DENG2_PIMPL(RemoteFile)
     Block remoteMetaId;
     Block buffer;
     RemoteFeedRelay::FileContentsRequest fetching;
-    //SafePtr<File const> cachedFile;
 
     Impl(Public *i) : Base(i) {}
 
@@ -150,9 +151,19 @@ void RemoteFile::fetchContents()
             File &data = cacheFolder.replaceFile(fn);
             data << d->buffer;
             d->buffer.clear();
-
             data.flush();
 
+            // Override the last modified time.
+            {
+                auto st = data.status();
+                st.modifiedAt = status().modifiedAt;
+                data.setStatus(st);
+
+                // Remember this for later as well.
+                DirectoryFeed::setFileModifiedTime(data.correspondingNativePath(),
+                                                   st.modifiedAt);
+            }
+
             setTarget(data.reinterpret());
 
             //            d->cachedFile.reset(&data);