InstantExtended: Adding InstantRestrictedIDCache.

chrome/common/instant_types.h

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_COMMON_INSTANT_TYPES_H_
 #define CHROME_COMMON_INSTANT_TYPES_H_
 
 #include <string>
 
 #include "base/string16.h"
 #include "content/public/common/page_transition_types.h"
 #include "googleurl/src/gurl.h"
 
+// ID used by Instant code to refer to objects (e.g. autocomplete results, most
+// visisted items) that the Instant page needs access to.

[dhollowa, 2013/03/14 00:02:43]

nit: "Autocomplete results", "Most Visited items"

[Shishir, 2013/03/14 19:53:03]

Done.

+typedef int InstantRestrictedID;

[palmer, 2013/03/13 23:50:37]

This should be an unsigned int (it never goes < 0, *and* it's used as an index
into a vector).

[dhollowa, 2013/03/14 00:02:43]

unsigned int

[Shishir, 2013/03/14 19:53:03]

From "base/basictypes.h"

// NOTE: unsigned types are DANGEROUS in loops and other arithmetical
// places.  Use the signed types unless your variable represents a bit
// pattern (eg a hash value) or you really need the extra bit.  Do NOT
// use 'unsigned' to express "this value should always be positive";
// use assertions for this.

I had made this uint first and then changed it after reading this.

[Shishir, 2013/03/14 19:53:03]

Ditto.

[dhollowa, 2013/03/14 23:40:00]

I'm fine with int.

[palmer, 2013/03/15 01:47:53]

That comment is wrong. The problem is when you compare types of different
signedness, not merely the use of unsigned types.

It's especially ironic that they say unsigned types are dangerous in other
arithmetical places" — signed types have *undefined* behavior when the
arithmetic overflows; only unsigned types have defined behavior.

Unsigned integers are the *correct* and *safe* types to use for sizes, offsets,
array and vector indices, and so on. Signed types are affirmatively *unsafe* in
those uses.

[Shishir, 2013/03/15 17:31:15]

With the current code there is no strict requirement that the number can't be
negative. There are no array like accesses any more, no std::max kind of stuff
so I think we can leave it an int.

+
 // Ways that the Instant suggested text is autocompleted into the omnibox.
 enum InstantCompleteBehavior {
   // Autocomplete the suggestion immediately.
   INSTANT_COMPLETE_NOW,
 
   // Do not autocomplete the suggestion. The suggestion may still be displayed
   // in the omnibox, but not made a part of the omnibox text by default (e.g.,
   // by displaying the suggestion as non-highlighted, non-selected gray text).
   INSTANT_COMPLETE_NEVER,
 
@@ skipping 41 matching lines @@
   string16 destination_url;
 
   // The transition type to use when the user opens this match. Same as
   // AutocompleteMatch::transition.
   content::PageTransition transition;
 
   // The relevance score of this match, same as AutocompleteMatch::relevance.
   int relevance;
 };
 
+// An InstantAutocompleteResult along with its assigned restricted ID.
+typedef std::pair<InstantRestrictedID, InstantAutocompleteResult>
+    InstantAutocompleteResultIDPair;
+
 // How to interpret the size (height or width) of the Instant overlay (preview).
 enum InstantSizeUnits {
   // As an absolute number of pixels.
   INSTANT_SIZE_PIXELS,
 
   // As a percentage of the height or width of the containing (parent) view.
   INSTANT_SIZE_PERCENT,
 };
 
 // What the Instant page contains when it requests to be shown.
@@ skipping 61 matching lines @@
 
   // The theme background image tiling is only valid if |theme_id| is valid.
   ThemeBackgroundImageTiling image_tiling;
 
   // The theme background image height.
   // Value is only valid if |theme_id| is valid.
   uint16 image_height;
 };
 
 struct InstantMostVisitedItem {
-  InstantMostVisitedItem() : most_visited_item_id(0) {}
-
-  // A private identifier used on the browser side when retrieving assets.
-  uint64 most_visited_item_id;
-
   // The URL of the Most Visited item.
   GURL url;
 
   // The title of the Most Visited page.  May be empty, in which case the |url|
   // is used as the title.
   string16 title;
 };
 
+// An InstantMostVisitedItem along with its assigned restricted ID.
+typedef std::pair<InstantRestrictedID, InstantMostVisitedItem>
+    InstantMostVisitedItemIDPair;
+
 #endif  // CHROME_COMMON_INSTANT_TYPES_H_