| // Copyright 2012 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef BASE_UUID_H_ |
| #define BASE_UUID_H_ |
| |
| #include <stdint.h> |
| |
| #include <compare> |
| #include <iosfwd> |
| #include <string> |
| |
| #include "base/base_export.h" |
| #include "base/containers/span.h" |
| #include "base/strings/string_piece.h" |
| #include "base/types/pass_key.h" |
| #include "build/build_config.h" |
| |
| namespace content { |
| class FileSystemAccessManagerImpl; |
| } |
| |
| namespace base { |
| |
| class BASE_EXPORT Uuid { |
| public: |
| // Length in bytes of the input required to format the input as a Uuid in the |
| // form of version 4. |
| static constexpr size_t kGuidV4InputLength = 16; |
| |
| // Generate a 128-bit random Uuid in the form of version 4. see RFC 4122, |
| // section 4.4. The format of Uuid version 4 must be |
| // xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx, where y is one of [8, 9, a, b]. The |
| // hexadecimal values "a" through "f" are output as lower case characters. |
| // A cryptographically secure random source will be used, but consider using |
| // UnguessableToken for greater type-safety if Uuid format is unnecessary. |
| static Uuid GenerateRandomV4(); |
| |
| // Formats a sequence of 16 random bytes as a Uuid in the form of version 4. |
| // `input` must: |
| // - have been randomly generated (e.g. created from an UnguessableToken), and |
| // - be of length 16 (this is checked at compile-time). |
| // Despite taking 128 bits of randomness, certain bits will always be |
| // masked over to adhere to the V4 Uuid format. |
| // Useful in cases where an opaque identifier that is generated from stable |
| // inputs needs to be formatted as a V4 Uuid. Currently only exposed to the |
| // File System Access API to return a V4 Uuid for the getUniqueId() method. |
| static Uuid FormatRandomDataAsV4( |
| base::span<const uint8_t, kGuidV4InputLength> input, |
| base::PassKey<content::FileSystemAccessManagerImpl> pass_key); |
| static Uuid FormatRandomDataAsV4ForTesting( |
| base::span<const uint8_t, kGuidV4InputLength> input); |
| |
| // Returns a valid Uuid if the input string conforms to the Uuid format, and |
| // an invalid Uuid otherwise. Note that this does NOT check if the hexadecimal |
| // values "a" through "f" are in lower case characters. |
| static Uuid ParseCaseInsensitive(StringPiece input); |
| static Uuid ParseCaseInsensitive(StringPiece16 input); |
| |
| // Similar to ParseCaseInsensitive(), but all hexadecimal values "a" through |
| // "f" must be lower case characters. |
| static Uuid ParseLowercase(StringPiece input); |
| static Uuid ParseLowercase(StringPiece16 input); |
| |
| // Constructs an invalid Uuid. |
| Uuid(); |
| |
| Uuid(const Uuid& other); |
| Uuid& operator=(const Uuid& other); |
| Uuid(Uuid&& other); |
| Uuid& operator=(Uuid&& other); |
| |
| bool is_valid() const { return !lowercase_.empty(); } |
| |
| // Returns the Uuid in a lowercase string format if it is valid, and an empty |
| // string otherwise. The returned value is guaranteed to be parsed by |
| // ParseLowercase(). |
| // |
| // NOTE: While AsLowercaseString() is currently a trivial getter, callers |
| // should not treat it as such. When the internal type of base::Uuid changes, |
| // this will be a non-trivial converter. See the TODO above `lowercase_` for |
| // more context. |
| const std::string& AsLowercaseString() const; |
| |
| // Invalid Uuids are equal. |
| friend bool operator==(const Uuid&, const Uuid&) = default; |
| // Uuids are 128bit chunks of data so must be indistinguishable if equivalent. |
| friend std::strong_ordering operator<=>(const Uuid&, const Uuid&) = default; |
| |
| private: |
| static Uuid FormatRandomDataAsV4Impl( |
| base::span<const uint8_t, kGuidV4InputLength> input); |
| |
| // TODO(crbug.com/1026195): Consider using a different internal type. |
| // Most existing representations of Uuids in the codebase use std::string, |
| // so matching the internal type will avoid inefficient string conversions |
| // during the migration to base::Uuid. |
| // |
| // The lowercase form of the Uuid. Empty for invalid Uuids. |
| std::string lowercase_; |
| }; |
| |
| // For runtime usage only. Do not store the result of this hash, as it may |
| // change in future Chromium revisions. |
| struct BASE_EXPORT UuidHash { |
| size_t operator()(const Uuid& uuid) const; |
| }; |
| |
| // Stream operator so Uuid objects can be used in logging statements. |
| BASE_EXPORT std::ostream& operator<<(std::ostream& out, const Uuid& uuid); |
| |
| } // namespace base |
| |
| #endif // BASE_UUID_H_ |