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// Copyright 2014 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 COMPONENTS_OMNIBOX_KEYWORD_PROVIDER_H_
#define COMPONENTS_OMNIBOX_KEYWORD_PROVIDER_H_
#include <string>
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/memory/scoped_ptr.h"
#include "components/metrics/proto/omnibox_input_type.pb.h"
#include "components/omnibox/autocomplete_input.h"
#include "components/omnibox/autocomplete_provider.h"
#include "components/omnibox/keyword_extensions_delegate.h"
class AutocompleteProviderListener;
class KeywordExtensionsDelegate;
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:
KeywordProvider(AutocompleteProviderListener* listener,
TemplateURLService* model);
void set_extensions_delegate(
scoped_ptr<KeywordExtensionsDelegate> extensions_delegate) {
extensions_delegate_ = extensions_delegate.Pass();
}
// 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:
void Start(const AutocompleteInput& input,
bool minimal_changes,
bool called_due_to_focus) override;
void Stop(bool clear_cached_results,
bool due_to_user_inactivity) override;
private:
friend class KeywordExtensionsDelegateImpl;
~KeywordProvider() override;
// 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(metrics::OmniboxInputType::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;
TemplateURLService* GetTemplateURLService() const;
AutocompleteProviderListener* listener_;
// Model for the keywords.
TemplateURLService* model_;
// Delegate to handle the extensions-only logic for KeywordProvider.
// NULL when extensions are not enabled. May be NULL for tests.
scoped_ptr<KeywordExtensionsDelegate> extensions_delegate_;
DISALLOW_COPY_AND_ASSIGN(KeywordProvider);
};
#endif // COMPONENTS_OMNIBOX_KEYWORD_PROVIDER_H_