// Copyright (c) 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.
//
// This file contains the keyword autocomplete provider. The keyword provider
// is responsible for remembering/suggesting user "search keyword queries"
// (e.g. "imdb Godzilla") and then fixing them up into valid URLs. An
// instance of it gets created and managed by the autocomplete controller.
// KeywordProvider uses a TemplateURLService to find the set of keywords.
#ifndef CHROME_BROWSER_AUTOCOMPLETE_KEYWORD_PROVIDER_H_
#define CHROME_BROWSER_AUTOCOMPLETE_KEYWORD_PROVIDER_H_
#include <string>
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "chrome/browser/autocomplete/autocomplete_input.h"
#include "chrome/browser/autocomplete/autocomplete_provider.h"
#include "content/public/browser/notification_observer.h"
#include "content/public/browser/notification_registrar.h"
class Profile;
class TemplateURL;
class TemplateURLService;
// Autocomplete provider for keyword input.
//
// After construction, the autocomplete controller repeatedly calls Start()
// with some user input, each time expecting to receive a small set of the best
// matches (either synchronously or asynchronously).
//
// To construct these matches, the provider treats user input as a series of
// whitespace-delimited tokens and tries to match the first token as the prefix
// of a known "keyword". A keyword is some string that maps to a search query
// URL; the rest of the user's input is taken as the input to the query. For
// example, the keyword "bug" might map to the URL "http://b/issue?id=%s", so
// input like "bug 123" would become "http://b/issue?id=123".
//
// Because we do prefix matching, user input could match more than one keyword
// at once. (Example: the input "f jazz" matches all keywords starting with
// "f".) We return the best matches, up to three.
//
// The resulting matches are shown with content specified by the keyword
// (usually "Search [name] for %s"), description "(Keyword: [keyword])", and
// action "[keyword] %s". If the user has typed a (possibly partial) keyword
// but no search terms, the suggested result is shown greyed out, with
// "<enter term(s)>" as the substituted input, and does nothing when selected.
class KeywordProvider : public AutocompleteProvider,
public content::NotificationObserver {
public:
KeywordProvider(AutocompleteProviderListener* listener, Profile* profile);
// For testing.
KeywordProvider(AutocompleteProviderListener* listener,
TemplateURLService* model);
// Extracts the next whitespace-delimited token from input and returns it.
// Sets |remaining_input| to everything after the first token (skipping over
// the first intervening whitespace).
// If |trim_leading_whitespace| is true then leading whitespace in
// |*remaining_input| will be trimmed.
static base::string16 SplitKeywordFromInput(const base::string16& input,
bool trim_leading_whitespace,
base::string16* remaining_input);
// Returns the replacement string from the user input. The replacement
// string is the portion of the input that does not contain the keyword.
// For example, the replacement string for "b blah" is blah.
// If |trim_leading_whitespace| is true then leading whitespace in
// replacement string will be trimmed.
static base::string16 SplitReplacementStringFromInput(
const base::string16& input,
bool trim_leading_whitespace);
// Returns the matching substituting keyword for |input|, or NULL if there
// is no keyword for the specified input. If the matching keyword was found,
// updates |input|'s text and cursor position.
static const TemplateURL* GetSubstitutingTemplateURLForInput(
TemplateURLService* model,
AutocompleteInput* input);
// If |text| corresponds (in the sense of
// TemplateURLModel::CleanUserInputKeyword()) to an enabled, substituting
// keyword, returns that keyword; returns the empty string otherwise.
base::string16 GetKeywordForText(const base::string16& text) const;
// Creates a fully marked-up AutocompleteMatch for a specific keyword.
AutocompleteMatch CreateVerbatimMatch(const base::string16& text,
const base::string16& keyword,
const AutocompleteInput& input);
// AutocompleteProvider:
virtual void Start(const AutocompleteInput& input,
bool minimal_changes) OVERRIDE;
virtual void Stop(bool clear_cached_results) OVERRIDE;
private:
class ScopedEndExtensionKeywordMode;
friend class ScopedEndExtensionKeywordMode;
virtual ~KeywordProvider();
// Extracts the keyword from |input| into |keyword|. Any remaining characters
// after the keyword are placed in |remaining_input|. Returns true if |input|
// is valid and has a keyword. This makes use of SplitKeywordFromInput to
// extract the keyword and remaining string, and uses
// TemplateURLService::CleanUserInputKeyword to remove unnecessary characters.
// In general use this instead of SplitKeywordFromInput.
// Leading whitespace in |*remaining_input| will be trimmed.
static bool ExtractKeywordFromInput(const AutocompleteInput& input,
base::string16* keyword,
base::string16* remaining_input);
// Determines the relevance for some input, given its type, whether the user
// typed the complete keyword, and whether the user is in "prefer keyword
// matches" mode, and whether the keyword supports replacement.
// If |allow_exact_keyword_match| is false, the relevance for complete
// keywords that support replacements is degraded.
static int CalculateRelevance(AutocompleteInput::Type type,
bool complete,
bool support_replacement,
bool prefer_keyword,
bool allow_exact_keyword_match);
// Creates a fully marked-up AutocompleteMatch from the user's input.
// If |relevance| is negative, calculate a relevance based on heuristics.
AutocompleteMatch CreateAutocompleteMatch(
const TemplateURL* template_url,
const AutocompleteInput& input,
size_t prefix_length,
const base::string16& remaining_input,
bool allowed_to_be_default_match,
int relevance);
// Fills in the "destination_url" and "contents" fields of |match| with the
// provided user input and keyword data.
void FillInURLAndContents(const base::string16& remaining_input,
const TemplateURL* element,
AutocompleteMatch* match) const;
void EnterExtensionKeywordMode(const std::string& extension_id);
void MaybeEndExtensionKeywordMode();
// content::NotificationObserver interface.
virtual void Observe(int type,
const content::NotificationSource& source,
const content::NotificationDetails& details) OVERRIDE;
TemplateURLService* GetTemplateURLService() const;
// Model for the keywords. This is only non-null when testing, otherwise the
// TemplateURLService from the Profile is used.
TemplateURLService* model_;
// Identifies the current input state. This is incremented each time the
// autocomplete edit's input changes in any way. It is used to tell whether
// suggest results from the extension are current.
int current_input_id_;
// The input state at the time we last asked the extension for suggest
// results.
AutocompleteInput extension_suggest_last_input_;
// We remember the last suggestions we've received from the extension in case
// we need to reset our matches without asking the extension again.
std::vector<AutocompleteMatch> extension_suggest_matches_;
// If non-empty, holds the ID of the extension whose keyword is currently in
// the URL bar while the autocomplete popup is open.
std::string current_keyword_extension_id_;
content::NotificationRegistrar registrar_;
DISALLOW_COPY_AND_ASSIGN(KeywordProvider);
};
#endif // CHROME_BROWSER_AUTOCOMPLETE_KEYWORD_PROVIDER_H_