linux: scan more plugin directories, fix bugs

We now scan more directories, sort file entries by mtime, use
realpath() before loading plugins (fixes a Java bug), and de-duplicate
multiple instances of the same plugin.
This matches the Mozilla plugin loading code more closely.

I encountered this while attempting to fix QuickTime (need to load
the Totem plugins) but the fix overlaps with the Java one.  I believe
neither quite work yet, though.

BUG=16787,19712
TEST=about:plugins should show more plugins

Review URL: http://codereview.chromium.org/173550

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@24611 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 61 insertions, 11 deletions

diff --git a/webkit/glue/plugins/plugin_list_linux.cc b/webkit/glue/plugins/plugin_list_linux.cc
index 2a92bbd..4c98146 100644
--- a/webkit/glue/plugins/plugin_list_linux.cc
+++ b/webkit/glue/plugins/plugin_list_linux.cc
@@ -7,6 +7,25 @@
 #include "base/file_util.h"
 #include "base/path_service.h"
 
+namespace {
+
+// We build up a list of files and mtimes so we can sort them.
+typedef std::pair<FilePath, base::Time> FileAndTime;
+typedef std::vector<FileAndTime> FileTimeList;
+
+// Comparator used to sort by descending mtime then ascending filename.
+bool CompareTime(const FileAndTime& a, const FileAndTime& b) {
+  if (a.second == b.second) {
+    // Fall back on filename sorting, just to make the predicate valid.
+    return a.first < b.first;
+  }
+
+  // Sort by mtime, descending.
+  return a.second > b.second;
+}
+
+}
+
 namespace NPAPI {
 
 void PluginList::PlatformInit() {
@@ -38,33 +57,64 @@ void PluginList::GetPluginDirectories(std::vector<FilePath>* plugin_dirs) {
   plugin_dirs->push_back(dir.Append("plugins"));
 
   // 4) NS_SYSTEM_PLUGINS_DIR:
-  // TODO(evanm): when we support 64-bit platforms, we'll need to fix this
-  // to be conditional.
-  COMPILE_ASSERT(sizeof(int)==4, fix_system_lib_path);
+  // This varies across different versions of Firefox, so check 'em all.
   plugin_dirs->push_back(FilePath("/usr/lib/mozilla/plugins"));
+  plugin_dirs->push_back(FilePath("/usr/lib/firefox/plugins"));
+  plugin_dirs->push_back(FilePath("/usr/lib/xulrunner-addons/plugins"));
 }
 
 void PluginList::LoadPluginsFromDir(const FilePath& path,
                                     std::vector<WebPluginInfo>* plugins) {
+  // See ScanPluginsDirectory near
+  // http://mxr.mozilla.org/firefox/source/modules/plugin/base/src/nsPluginHostImpl.cpp#5052
+
+  // Construct and stat a list of all filenames under consideration, for
+  // later sorting by mtime.
+  FileTimeList files;
   file_util::FileEnumerator enumerator(path,
                                        false, // not recursive
                                        file_util::FileEnumerator::FILES);
   for (FilePath path = enumerator.Next(); !path.value().empty();
        path = enumerator.Next()) {
     // Skip over Mozilla .xpt files.
-    if (!path.MatchesExtension(FILE_PATH_LITERAL(".xpt")))
-      LoadPlugin(path, plugins);
+    if (path.MatchesExtension(FILE_PATH_LITERAL(".xpt")))
+      continue;
+
+    // Java doesn't like being loaded through a symlink, since it uses
+    // its path to find dependent data files.
+    // file_util::AbsolutePath calls through to realpath(), which resolves
+    // symlinks.
+    file_util::AbsolutePath(&path);
+
+    // Get mtime.
+    file_util::FileInfo info;
+    if (!file_util::GetFileInfo(path, &info))
+      continue;
+
+    files.push_back(std::make_pair(path, info.last_modified));
+  }
+
+  // Sort the file list by time (and filename).
+  std::sort(files.begin(), files.end(), CompareTime);
+
+  // Load the files in order.
+  for (FileTimeList::const_iterator i = files.begin(); i != files.end(); ++i) {
+    LoadPlugin(i->first, plugins);
   }
 }
 
 bool PluginList::ShouldLoadPlugin(const WebPluginInfo& info,
                                   std::vector<WebPluginInfo>* plugins) {
-  // The equivalent Windows code verifies we haven't loaded a newer version
-  // of the same plugin, and then blacklists some known bad plugins.
-  // The equivalent Mac code verifies that plugins encountered first in the
-  // plugin list clobber later entries.
-  // TODO(evanm): figure out which behavior is appropriate for Linux.
-  // We don't need either yet as I'm just testing with Flash for now.
+  // Skip loading an additional instance of the same file.  (This can
+  // occur due to symlinks from the multiple plugin paths we search.)
+  for (size_t i = 0; i < plugins->size(); ++i) {
+    if (info.path == plugins->at(i).path)
+      return false;
+  }
+
+  // TODO(evanm): blacklist nspluginwrapper here?
+  // TODO(evanm): prefer the newest version of flash here?
+
   return true;
 }