chromium/components/omnibox/browser/keyword_provider.h

// Copyright 2014 The Chromium Authors
// 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_BROWSER_KEYWORD_PROVIDER_H_
#define COMPONENTS_OMNIBOX_BROWSER_KEYWORD_PROVIDER_H_

#include <stddef.h>

#include <memory>
#include <string>
#include <utility>

#include "base/compiler_specific.h"
#include "base/memory/raw_ptr.h"
#include "components/omnibox/browser/autocomplete_input.h"
#include "components/omnibox/browser/autocomplete_provider.h"
#include "components/omnibox/browser/keyword_extensions_delegate.h"
#include "third_party/metrics_proto/omnibox_input_type.pb.h"

class AutocompleteProviderClient;
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 {};

#endif  // COMPONENTS_OMNIBOX_BROWSER_KEYWORD_PROVIDER_H_