Implement a simple Extension App Omnibox provider.

chrome/browser/autocomplete/extension_app_provider.cc

+// Copyright (c) 2011 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.
+
+#include "chrome/browser/autocomplete/extension_app_provider.h"
+
+#include <algorithm>
+#include <cmath>
+
+#include "base/string16.h"
+#include "base/utf_string_conversions.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/history/history.h"
+#include "chrome/browser/history/url_database.h"
+#include "chrome/browser/profiles/profile.h"
+#include "content/common/notification_service.h"
+#include "ui/base/l10n/l10n_util.h"
+
+ExtensionAppProvider::ExtensionAppProvider(ACProviderListener* listener,
+                                           Profile* profile)
+    : AutocompleteProvider(listener, profile, "ExtensionApps") {
+  RegisterForNotifications();
+  RefreshAppList();
+}
+
+void ExtensionAppProvider::Start(const AutocompleteInput& input,
+                                 bool minimal_changes) {
+  matches_.clear();
+
+  if (input.type() == AutocompleteInput::INVALID)
+    return;
+
+  if (!input.text().empty()) {
+    std::string input_utf8 = UTF16ToUTF8(input.text());
+    for (ExtensionApps::const_iterator app = extension_apps_.begin();
+         app != extension_apps_.end(); ++app) {
+      // See if the input matches this extension application.
+      const std::string& name = app->first;
+      const std::string& url = app->second;
+      std::string::const_iterator name_iter =
+          std::search(name.begin(),
+                      name.end(),
+                      input_utf8.begin(),
+                      input_utf8.end(),
+                      base::CaseInsensitiveCompare<char>());
+      std::string::const_iterator url_iter =
+          std::search(url.begin(),
+                      url.end(),
+                      input_utf8.begin(),
+                      input_utf8.end(),
+                      base::CaseInsensitiveCompare<char>());
+
+      bool matches_name = name_iter != name.end();
+      bool matches_url = url_iter != url.end() &&
+                         input.type() != AutocompleteInput::FORCED_QUERY;
+      if (matches_name || matches_url) {
+        // We have a match, might be a partial match.
+        // TODO(finnur): Figure out what type to return here, might want to have
+        // the extension icon/a generic icon show up in the Omnibox.
+        AutocompleteMatch match(this, 0, false, AutocompleteMatch::HISTORY_URL);
+        match.fill_into_edit = UTF8ToUTF16(url);
+        match.destination_url = GURL(url);
+        match.inline_autocomplete_offset = string16::npos;
+        match.contents = UTF8ToUTF16(name);
+        HighlightMatch(input, &match.contents_class, name_iter, name);
+        match.description = UTF8ToUTF16(url);
+        HighlightMatch(input, &match.description_class, url_iter, url);
+        match.relevance = CalculateRelevance(input.type(),
+                                             input.text().length(),
+                                             matches_name ?
+                                                 name.length() : url.length(),
+                                             GURL(url));
+        matches_.push_back(match);
+      }
+    }
+  }
+}
+
+ExtensionAppProvider::~ExtensionAppProvider() {
+}
+
+void ExtensionAppProvider::RefreshAppList() {
+  ExtensionService* extension_service = profile_->GetExtensionService();
+  if (!extension_service)
+    return;  // During testing, there is no extension service.
+  const ExtensionList* extensions = extension_service->extensions();
+  extension_apps_.clear();
+  for (ExtensionList::const_iterator app = extensions->begin();
+       app != extensions->end(); ++app) {
+    if ((*app)->is_app() && !(*app)->launch_web_url().empty()) {
+      extension_apps_.push_back(std::make_pair((*app)->name(),
+                                               (*app)->launch_web_url()));
+    }
+  }
+}
+
+void ExtensionAppProvider::RegisterForNotifications() {
+  registrar_.Add(this, NotificationType::EXTENSION_LOADED,
+                 NotificationService::AllSources());
+  registrar_.Add(this, NotificationType::EXTENSION_UNINSTALLED,
+                 NotificationService::AllSources());
+}
+
+void ExtensionAppProvider::Observe(NotificationType type,
+                                   const NotificationSource& source,
+                                   const NotificationDetails& details) {
+  RefreshAppList();
+}
+
+void ExtensionAppProvider::HighlightMatch(const AutocompleteInput& input,
+                                          ACMatchClassifications* match_class,
+                                          std::string::const_iterator iter,
+                                          const std::string& match_string) {
+  size_t pos = iter - match_string.begin();
+  bool match_found = iter != match_string.end();
+  if (!match_found || pos > 0) {
+    match_class->push_back(
+        ACMatchClassification(0, ACMatchClassification::DIM));
+  }
+  if (match_found) {
+    match_class->push_back(
+        ACMatchClassification(pos, ACMatchClassification::MATCH));
+    if (pos + input.text().length() < match_string.length()) {
+      match_class->push_back(ACMatchClassification(pos + input.text().length(),
+                                ACMatchClassification::DIM));
+    }
+  }
+}
+
+int ExtensionAppProvider::CalculateRelevance(AutocompleteInput::Type type,
+                                             int input_length,
+                                             int target_length,
+                                             const GURL& url) {
+  // If you update the algorithm here, please remember to update the tables in
+  // autocomplete.h also.
+  const int kMaxRelevance = 1425;
+
+  if (input_length == target_length)
+    return kMaxRelevance;
+
+  // We give a boost proportionally based on how much of the input matches the
+  // app name, up to a maximum close to 200 (we can be close to, but we'll never
+  // reach 200 because the 100% match is taken care of above).
+  double fraction_boost = static_cast<double>(200) *
+                          input_length / target_length;
+
+  // We also give a boost relative to how often the user has previously typed
+  // the Extension App URL/selected the Extension App suggestion from this
+  // provider (boost is between 200-400).
+  double type_count_boost = 0;
+  HistoryService* const history_service =
+      profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
+  history::URLDatabase* url_db = history_service ?
+      history_service->InMemoryDatabase() : NULL;
+  if (url_db) {
+    history::URLRow info;
+    url_db->GetRowForURL(url, &info);
+    type_count_boost =
+        400 * (1.0 - (std::pow(static_cast<double>(2), -info.typed_count())));
+  }
+  int relevance = 575 + static_cast<int>(type_count_boost) +
+                        static_cast<int>(fraction_boost);
+  DCHECK_LE(relevance, kMaxRelevance);
+  return relevance;
+}