text: // 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.
  
  #include "chrome/browser/autocomplete/history_provider.h"
  
  #include <string>
  
  #include "base/string_util.h"
  #include "base/utf_string_conversions.h"
  #include "chrome/browser/autocomplete/autocomplete_input.h"
  #include "chrome/browser/autocomplete/autocomplete_match.h"
  #include "chrome/browser/autocomplete/autocomplete_provider_listener.h"
  #include "chrome/browser/history/history.h"
  #include "chrome/browser/history/history_service_factory.h"
  #include "chrome/browser/net/url_fixer_upper.h"
  #include "chrome/browser/profiles/profile.h"
  #include "chrome/common/url_constants.h"
  #include "googleurl/src/url_util.h"
  
  HistoryProvider::HistoryProvider(AutocompleteProviderListener* listener,
                                   Profile* profile,
                                   AutocompleteProvider::Type type)
      : AutocompleteProvider(listener, profile, type),
        always_prevent_inline_autocomplete_(false) {
  }
  
  void HistoryProvider::DeleteMatch(const AutocompleteMatch& match) {
    DCHECK(done_);
    DCHECK(profile_);
    DCHECK(match.deletable);
  
    HistoryService* const history_service =
        HistoryServiceFactory::GetForProfile(profile_, Profile::EXPLICIT_ACCESS);
  
    // Delete the match from the history DB.
    DCHECK(history_service);
    DCHECK(match.destination_url.is_valid());
    history_service->DeleteURL(match.destination_url);
    DeleteMatchFromMatches(match);
  }
  
  HistoryProvider::~HistoryProvider() {}
  
  void HistoryProvider::DeleteMatchFromMatches(const AutocompleteMatch& match) {
    bool found = false;
    for (ACMatches::iterator i(matches_.begin()); i != matches_.end(); ++i) {
      if (i->destination_url == match.destination_url && i->type == match.type) {
        found = true;
        if (i->is_history_what_you_typed_match || i->starred) {
          // We can't get rid of What-You-Typed or Bookmarked matches,
          // but we can make them look like they have no backing data.
          i->deletable = false;
          i->description.clear();
          i->description_class.clear();
        } else {
          matches_.erase(i);
        }
        break;
      }
    }
    DCHECK(found) << "Asked to delete a URL that isn't in our set of matches";
    listener_->OnProviderUpdate(true);
  }
  
  // static
  bool HistoryProvider::FixupUserInput(AutocompleteInput* input) {
    const string16& input_text = input->text();
    // Fixup and canonicalize user input.
    // NOTE: This purposefully doesn't take input.desired_tld() into account; if
    // it did, then holding "ctrl" would change all the results from the provider,
    // not just the What You Typed Result.
    const GURL canonical_gurl(URLFixerUpper::FixupURL(UTF16ToUTF8(input_text),
                                                      std::string()));
    std::string canonical_gurl_str(canonical_gurl.possibly_invalid_spec());
    if (canonical_gurl_str.empty()) {
      // This probably won't happen, but there are no guarantees.
      return false;
    }
  
    // If the user types a number, GURL will convert it to a dotted quad.
    // However, if the parser did not mark this as a URL, then the user probably
    // didn't intend this interpretation.  Since this can break history matching
    // for hostname beginning with numbers (e.g. input of "17173" will be matched
    // against "0.0.67.21" instead of the original "17173", failing to find
    // "17173.com"), swap the original hostname in for the fixed-up one.
    if ((input->type() != AutocompleteInput::URL) &&
        canonical_gurl.HostIsIPAddress()) {
      std::string original_hostname =
          UTF16ToUTF8(input_text.substr(input->parts().host.begin,
                                        input->parts().host.len));
      const url_parse::Parsed& parts =
          canonical_gurl.parsed_for_possibly_invalid_spec();
      // parts.host must not be empty when HostIsIPAddress() is true.
      DCHECK(parts.host.is_nonempty());
      canonical_gurl_str.replace(parts.host.begin, parts.host.len,
                                 original_hostname);
    }
    string16 output = UTF8ToUTF16(canonical_gurl_str);
    // Don't prepend a scheme when the user didn't have one.  Since the fixer
    // upper only prepends the "http" scheme, that's all we need to check for.
    if (canonical_gurl.SchemeIs(chrome::kHttpScheme) &&
        !url_util::FindAndCompareScheme(UTF16ToUTF8(input_text),
                                        chrome::kHttpScheme, NULL))
      TrimHttpPrefix(&output);
  
    // Make the number of trailing slashes on the output exactly match the input.
    // Examples of why not doing this would matter:
    // * The user types "a" and has this fixed up to "a/".  Now no other sites
    //   beginning with "a" will match.
    // * The user types "file:" and has this fixed up to "file://".  Now inline
    //   autocomplete will append too few slashes, resulting in e.g. "file:/b..."
    //   instead of "file:///b..."
    // * The user types "http:/" and has this fixed up to "http:".  Now inline
    //   autocomplete will append too many slashes, resulting in e.g.
    //   "http:///c..." instead of "http://c...".
    // NOTE: We do this after calling TrimHttpPrefix() since that can strip
    // trailing slashes (if the scheme is the only thing in the input).  It's not
    // clear that the result of fixup really matters in this case, but there's no
    // harm in making sure.
    const size_t last_input_nonslash =
        input_text.find_last_not_of(ASCIIToUTF16("/\\"));
    const size_t num_input_slashes = (last_input_nonslash == string16::npos) ?
        input_text.length() : (input_text.length() - 1 - last_input_nonslash);
    const size_t last_output_nonslash =
        output.find_last_not_of(ASCIIToUTF16("/\\"));
    const size_t num_output_slashes =
        (last_output_nonslash == string16::npos) ?
        output.length() : (output.length() - 1 - last_output_nonslash);
    if (num_output_slashes < num_input_slashes)
      output.append(num_input_slashes - num_output_slashes, '/');
    else if (num_output_slashes > num_input_slashes)
      output.erase(output.length() - num_output_slashes + num_input_slashes);
  
    url_parse::Parsed parts;
    URLFixerUpper::SegmentURL(output, &parts);
    // TODO: This function does not take into account the cursor position while
    // running various normalizations, including a call to FixupURL(). In order
    // to make it work properly, we need to ensure that all logic above is
    // cursor-aware and offsets the input cursor accordingly.
    // For now we simply pretend that the cursor was not set at all.
    // See http://crbug/163932 for more details.
    input->UpdateText(output, string16::npos, parts);
    return !output.empty();
  }
  
  // static
  size_t HistoryProvider::TrimHttpPrefix(string16* url) {
    // Find any "http:".
    if (!HasHTTPScheme(*url))
      return 0;
    size_t scheme_pos =
        url->find(ASCIIToUTF16(chrome::kHttpScheme) + char16(':'));
    DCHECK_NE(string16::npos, scheme_pos);
  
    // Erase scheme plus up to two slashes.
    size_t prefix_end = scheme_pos + strlen(chrome::kHttpScheme) + 1;
    const size_t after_slashes = std::min(url->length(), prefix_end + 2);
    while ((prefix_end < after_slashes) && ((*url)[prefix_end] == '/'))
      ++prefix_end;
    url->erase(scheme_pos, prefix_end - scheme_pos);
    return (scheme_pos == 0) ? prefix_end : 0;
  }
  
  // static
  bool HistoryProvider::PreventInlineAutocomplete(
      const AutocompleteInput& input) {
    return input.prevent_inline_autocomplete() ||
        always_prevent_inline_autocomplete_ ||
        (!input.text().empty() &&
         IsWhitespace(input.text()[input.text().length() - 1]));
  }
  