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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_REGEXES_H_
#define COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_REGEXES_H_
#include <map>
#include <memory>
#include <string>
#include <string_view>
#include <vector>
#include "base/no_destructor.h"
#include "base/sequence_checker.h"
#include "base/synchronization/lock.h"
#include "base/types/strong_alias.h"
#include "third_party/icu/source/i18n/unicode/regex.h"
namespace autofill {
using ThreadSafe = base::StrongAlias<struct ThreadSafeTag, bool>;
// Compiles a case-insensitive regular expression.
//
// The return icu::RegexPattern is thread-safe (because it's const and icu
// guarantees thread-safety of the const functions). In particularly this
// includes icu::RegexPattern::matcher().
//
// May also be used to initialize `static base::NoDestructor<icu::RegexPattern>`
// function-scope variables.
std::unique_ptr<const icu::RegexPattern> CompileRegex(
std::u16string_view regex);
// Returns true if `regex` is found in `input`.
// If `groups` is non-null, it gets resized and the found capture groups
// are written into it.
// Thread-safe.
bool MatchesRegex(std::u16string_view input,
const icu::RegexPattern& regex_pattern,
std::vector<std::u16string>* groups = nullptr);
// Calls MatchesRegex() after compiling the `regex` on the first call and
// retrieving it from a static variable in subsequent calls.
//
// This function is thread-safe.
template <const char16_t regex[]>
bool MatchesRegex(std::u16string_view input,
std::vector<std::u16string>* groups = nullptr) {
static base::NoDestructor<std::unique_ptr<const icu::RegexPattern>>
regex_pattern(CompileRegex(regex));
return MatchesRegex(input, **regex_pattern, groups);
}
// Splits `input` into up to `max_groups` segments. Returns a vector of segments
// in case of success or `std::nullopt` otherwise.
std::optional<std::vector<std::u16string>> SplitByRegex(
std::u16string_view input,
const icu::RegexPattern& regex_pattern,
size_t max_groups);
// A cache of compiled regex patterns. It can be configured to be thread-safe
// (using a mutex) or not (in which case it uses a sequence checker).
class AutofillRegexCache {
public:
explicit AutofillRegexCache(ThreadSafe thread_safe);
~AutofillRegexCache();
AutofillRegexCache(const AutofillRegexCache&) = delete;
AutofillRegexCache& operator=(const AutofillRegexCache&) = delete;
// Returns the compiled regex corresponding to `regex`.
// This function is thread-safe if `thread_safe_`.
// The returned object is thread-safe in any case (because it's const).
// Although the returned pointer is guaranteed to be non-nullptr, we do not
// return a reference to avoid accidental copies.
const icu::RegexPattern* GetRegexPattern(std::u16string_view regex);
private:
// `MatchesPattern()` uses the lock if `thread_safe_`. Otherwise, it validates
// the sequence.
ThreadSafe thread_safe_{false};
base::Lock lock_;
SEQUENCE_CHECKER(sequence_checker_);
// Maps regex strings to their corresponding compiled regex patterns.
std::
map<std::u16string, std::unique_ptr<const icu::RegexPattern>, std::less<>>
cache_;
};
} // namespace autofill
#endif // COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_REGEXES_H_
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