[Files Ranking] Removed deleted local files from the model.

We always check if a file exists before returning it as a candidate
search result. This CL adds to that so that if we find a file doesn't
exist, we remove it from the model.

Bug: 959697
Change-Id: I2ddca3015a265a9ef3910e6447872f92404a6922
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1775954Reviewed-by: Jia Meng <jiameng@chromium.org>
Commit-Queue: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#692387}

chrome/browser/ui/app_list/search/zero_state_file_provider.cc

@@ -23,16 +23,14 @@ using file_manager::file_tasks::FileTasksObserver;
 namespace app_list {
 namespace {
 
-using StringResults = std::vector<std::pair<std::string, float>>;
-using FilePathResults = std::vector<std::pair<base::FilePath, float>>;
-
 constexpr int kMaxLocalFiles = 10;
 
-// Given the output of RecurrenceRanker::RankTopN, filter out all results that
-// don't exist on disk. Returns the filtered results, with each result string
-// converted to a base::FilePath.
-FilePathResults FilterNonexistentFiles(const StringResults& ranker_results) {
-  FilePathResults results;
+// Given the output of RecurrenceRanker::RankTopN, partition files by whether
+// they exist or not on disk. Returns a pair of vectors: <valid, invalid>.
+internal::ValidAndInvalidResults ValidateFiles(
+    const std::vector<std::pair<std::string, float>>& ranker_results) {
+  internal::ScoredResults valid;
+  internal::Results invalid;
   for (const auto& path_score : ranker_results) {
     // We use FilePath::FromUTF8Unsafe to decode the filepath string. As per its
     // documentation, this is a safe use of the function because
@@ -40,9 +38,11 @@ FilePathResults FilterNonexistentFiles(const StringResults& ranker_results) {
     // filepaths are UTF8.
     const auto& path = base::FilePath::FromUTF8Unsafe(path_score.first);
     if (base::PathExists(path))
-      results.emplace_back(path, path_score.second);
+      valid.emplace_back(path, path_score.second);
+    else
+      invalid.emplace_back(path);
   }
-  return results;
+  return {valid, invalid};
 }
 
 }  // namespace
@@ -84,15 +84,20 @@ void ZeroStateFileProvider::Start(const base::string16& query) {
 
   base::PostTaskAndReplyWithResult(
       task_runner_.get(), FROM_HERE,
-      base::BindOnce(&FilterNonexistentFiles,
-                     files_ranker_->RankTopN(kMaxLocalFiles)),
+      base::BindOnce(&ValidateFiles, files_ranker_->RankTopN(kMaxLocalFiles)),
       base::BindOnce(&ZeroStateFileProvider::SetSearchResults,
                      weak_factory_.GetWeakPtr()));
 }
 
-void ZeroStateFileProvider::SetSearchResults(FilePathResults results) {
+void ZeroStateFileProvider::SetSearchResults(
+    const internal::ValidAndInvalidResults& results) {
+  // Delete invalid results from the model.
+  for (const auto& path : results.second)
+    files_ranker_->RemoveTarget(path.value());
+
+  // Use valid results for search results.
   SearchProvider::Results new_results;
-  for (const auto& filepath_score : results) {
+  for (const auto& filepath_score : results.first) {
     new_results.emplace_back(std::make_unique<ZeroStateFileResult>(
         filepath_score.first, filepath_score.second, profile_));
   }

chrome/browser/ui/app_list/search/zero_state_file_provider.h

@@ -28,6 +28,13 @@ class FileTasksNotifier;
 }  // namespace file_manager
 
 namespace app_list {
+namespace internal {
+
+using Results = std::vector<base::FilePath>;
+using ScoredResults = std::vector<std::pair<base::FilePath, float>>;
+using ValidAndInvalidResults = std::pair<ScoredResults, Results>;
+
+}  // namespace internal
 
 class RecurrenceRanker;
 
@@ -45,9 +52,10 @@ class ZeroStateFileProvider : public SearchProvider,
   void OnFilesOpened(const std::vector<FileOpenEvent>& file_opens) override;
 
  private:
-  // Converts |results| into ZeroStateFilesResults and sets them as this
-  // provider's results.
-  void SetSearchResults(std::vector<std::pair<base::FilePath, float>> results);
+  // Takes a pair of vectors: <valid paths, invalid paths>, and converts the
+  // valid paths to ZeroStatFilesResults and sets them as this provider's
+  // results. The invalid paths are removed from the model.
+  void SetSearchResults(const internal::ValidAndInvalidResults& results);
 
   // The reference to profile to get ZeroStateFileProvider service.
   Profile* const profile_;