Embed address normalization rewriting rules.

components/autofill/core/browser/address_rewriter.cc

+// Copyright 2016 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 "components/autofill/core/browser/address_rewriter.h"
+
+#include <memory>
+#include <unordered_map>
+
+#include "base/i18n/case_conversion.h"
+#include "base/memory/singleton.h"
+#include "base/strings/utf_string_conversions.h"
+#include "third_party/re2/src/re2/re2.h"
+
+namespace autofill {
+namespace {
+
+// Import in the internal rule table symbols. The data is defined in
+// components/autofill/core/browser/address_rewriter_rules.cc
+using internal::Rule;
+using internal::RegionInfo;
+using internal::kRuleTable;
+using internal::kRuleTableSize;
+
+// Aliases for the types used by the compiled rules cache.
+using CompiledRule = std::pair<std::unique_ptr<re2::RE2>, re2::StringPiece>;
+using CompiledRuleVector = std::vector<CompiledRule>;
+using CompiledRuleCache = std::unordered_map<std::string, CompiledRuleVector>;
+
+// Helper function to find the rules associated with |region|. Note that this
+// requires that kRuleTable be sorted by region.
+static const RegionInfo* GetRegionInfo(const base::StringPiece& region) {
+  const RegionInfo* begin = kRuleTable;
+  const RegionInfo* end = kRuleTable + kRuleTableSize;
+  const RegionInfo* iter = std::lower_bound(begin, end, region);
+  if (iter != end && region == iter->region)
+    return iter;
+  return nullptr;
+}
+
+// The cache of compiled string replacement rules, keyed by region. This class
+// is a singleton that compiles the rules for a given region the first time
+// they are requested.
+class Cache {
+ public:
+  // Return the singleton instance of the cache.
+  static Cache* GetInstance() { return base::Singleton<Cache>::get(); }
+
+  // If the rules for |region| have already been compiled and cached, return a
+  // pointer to them. Otherwise, find the rules for |region| (returning nullptr
+  // if there are no such rules exist), compile them, cache them, and return a
+  // pointer to the cached rules.
+  const CompiledRuleVector* GetRulesForRegion(const std::string& region) {
+    // Take the lock so that we don't update the data cache concurrently. Note
+    // that the returned data is const and can be concurrently accessed, just
+    // not the data cache.
+    base::AutoLock auto_lock(lock_);
+
+    // If we find a cached set of rules, return a pointer to the data.
+    CompiledRuleCache::iterator cache_iter = data_.find(region);
+    if (cache_iter != data_.end())
+      return &cache_iter->second;
+
+    // Cache miss. Look for the raw rules. If none, then return nullptr.
+    const RegionInfo* region_info = GetRegionInfo(region);
+    if (region_info == nullptr)
+      return nullptr;
+
+    // Add a new rule vector the the cache and populate it with compiled rules.
+    re2::RE2::Options options;
+    options.set_utf8(true);
+    options.set_word_boundary(true);
+    CompiledRuleVector& compiled_rules = data_[region];
+    compiled_rules.reserve(region_info->num_rules);
+    for (size_t i = 0; i < region_info->num_rules; ++i) {
+      const Rule& rule = region_info->rules[i];
+      std::unique_ptr<re2::RE2> pattern(new re2::RE2(rule.pattern, options));
+      re2::StringPiece rewrite(rule.rewrite);
+      compiled_rules.emplace_back(std::move(pattern), std::move(rewrite));
+    }
+
+    // Return a pointer to the data.
+    return &compiled_rules;
+  }
+
+ private:
+  Cache() {}
+
+  // Synchronizes access to |data_|, ensuring that a given set of rules is
+  // only compiled once.
+  base::Lock lock_;
+
+  // The cache of compiled rules, keyed by region.
+  CompiledRuleCache data_;
+
+  friend struct base::DefaultSingletonTraits<Cache>;
+  DISALLOW_COPY_AND_ASSIGN(Cache);
+};
+
+}  // namespace
+
+AddressRewriter AddressRewriter::ForCountryCode(
+    const base::string16& country_code) {
+  const std::string region =
+      base::UTF16ToUTF8(base::i18n::ToUpper(country_code));
+  const CompiledRuleVector* rules =
+      Cache::GetInstance()->GetRulesForRegion(region);
+  AddressRewriter rewriter;
+  rewriter.impl_ = rules;
+  return rewriter;
+}
+
+base::string16 AddressRewriter::Rewrite(const base::string16& text) const {
+  if (impl_ == nullptr)
+    return base::CollapseWhitespace(text, true);
+
+  // Apply all of the string replacement rules. We don't have to worry about
+  // whitespace during these passes because the patterns are all whitespace
+  // tolerant regular expressions.
+  std::string utf8_text = base::UTF16ToUTF8(text);
+  for (const auto& rule : *static_cast<const CompiledRuleVector*>(impl_)) {
+    RE2::GlobalReplace(&utf8_text, *rule.first, rule.second);
+  }
+
+  // Collapse whitespace before returning the final value.
+  return base::UTF8ToUTF16(base::CollapseWhitespaceASCII(utf8_text, true));
+}
+
+}  // namespace autofill