Omnibox: Truncate HistoryContents Searches at 10k Characters

chrome/browser/autocomplete/history_contents_provider.cc

Index: chrome/browser/autocomplete/history_contents_provider.cc
diff --git a/chrome/browser/autocomplete/history_contents_provider.cc b/chrome/browser/autocomplete/history_contents_provider.cc
index 190d0a3afc85bbd3186f5ca0caeda03bd8bdfa81..d6219523e9f3e62cec56c1ec010612832fdb7e95 100644
--- a/chrome/browser/autocomplete/history_contents_provider.cc
+++ b/chrome/browser/autocomplete/history_contents_provider.cc
@@ -31,6 +31,15 @@ namespace {
 // time it will take.
 const int kDaysToSearch = 30;
 
+// The maximum number of characters used in a search for full text results.
+// This was chosen arbitrarily because omnibox results that come back too
+// late (after tens of seconds) aren't useful to the user so it's not
+// worth spending CPU time on them.  Furthermore, if a URL matches the
+// first 2k of characters the user typed (more likely pasted) into the
+// omnibox, it's likely it matches the rest; there's strongly diminished
+// returns for the ability to add additional search terms.
+const size_t kMaxCharactersToConsider = 2000u;

[Peter Kasting, 2013/04/17 22:59:45]

Nit: Since this is only used in one function I suggest declaring it in the most
local scope there.  (This could be done with kDaysToSearch too.)

[Mark P, 2013/04/17 23:06:48]

I kind of like having parameters called out somewhere, like this, at the top of
a file.  Besides that function is kind of long already; this would add another
doezen lines to it.

If you insist I'll do it.

[Peter Kasting, 2013/04/17 23:09:01]

I don't care strongly.  I always read the style guide's "declare things in the
most local scope possible" as applying to constants too, so that's the source of
the suggestion.  Up to you whether you agree with that interpretation.

[Mark P, 2013/04/17 23:13:28]

Okay, done.

+
 }  // namespace
 
 HistoryContentsProvider::MatchReference::MatchReference(
@@ -139,7 +148,9 @@ void HistoryContentsProvider::Start(const AutocompleteInput& input,
       options.body_only = body_only_;
       options.SetRecentDayRange(kDaysToSearch);
       options.max_count = kMaxMatches;
-      history->QueryHistory(input.text(), options,
+      history->QueryHistory(
+          input.text().substr(0, kMaxCharactersToConsider),
+          options,
           &request_consumer_,
           base::Bind(&HistoryContentsProvider::QueryComplete,
                      base::Unretained(this)));