| // 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_GUID_H_ |
| #define BASE_GUID_H_ |
| |
| #include <stdint.h> |
| |
| #include <iosfwd> |
| #include <string> |
| |
| #include "base/base_export.h" |
| #include "base/containers/span.h" |
| #include "base/hash/hash.h" |
| #include "base/strings/string_piece.h" |
| #include "base/types/pass_key.h" |
| #include "build/build_config.h" |
| |
| namespace content { |
| class FileSystemAccessManagerImpl; |
| } |
| |
| namespace base { |
| |
| // DEPRECATED, use GUID::GenerateRandomV4() instead. |
| BASE_EXPORT std::string GenerateGUID(); |
| |
| // DEPRECATED, use GUID::ParseCaseInsensitive() and GUID::is_valid() instead. |
| BASE_EXPORT bool IsValidGUID(StringPiece input); |
| BASE_EXPORT bool IsValidGUID(StringPiece16 input); |
| |
| // DEPRECATED, use GUID::ParseLowercase() and GUID::is_valid() instead. |
| BASE_EXPORT bool IsValidGUIDOutputString(StringPiece input); |
| |
| // For unit testing purposes only. Do not use outside of tests. |
| BASE_EXPORT std::string RandomDataToGUIDString(const uint64_t bytes[2]); |
| |
| class BASE_EXPORT GUID { |
| public: |
| // Length in bytes of the input required to format the input as a GUID in the |
| // form of version 4. |
| static constexpr size_t kGuidV4InputLength = 16; |
| |
| // Generate a 128-bit random GUID in the form of version 4. see RFC 4122, |
| // section 4.4. The format of GUID 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 GUID format is unnecessary. |
| static GUID GenerateRandomV4(); |
| |
| // Formats a sequence of 16 random bytes as a GUID 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 GUID format. |
| // Useful in cases where an opaque identifier that is generated from stable |
| // inputs needs to be formatted as a V4 GUID. Currently only exposed to the |
| // File System Access API to return a V4 GUID for the getUniqueId() method. |
| static GUID FormatRandomDataAsV4( |
| base::span<const uint8_t, kGuidV4InputLength> input, |
| base::PassKey<content::FileSystemAccessManagerImpl> pass_key); |
| static GUID FormatRandomDataAsV4ForTesting( |
| base::span<const uint8_t, kGuidV4InputLength> input); |
| |
| // Returns a valid GUID if the input string conforms to the GUID format, and |
| // an invalid GUID otherwise. Note that this does NOT check if the hexadecimal |
| // values "a" through "f" are in lower case characters. |
| static GUID ParseCaseInsensitive(StringPiece input); |
| static GUID ParseCaseInsensitive(StringPiece16 input); |
| |
| // Similar to ParseCaseInsensitive(), but all hexadecimal values "a" through |
| // "f" must be lower case characters. |
| static GUID ParseLowercase(StringPiece input); |
| static GUID ParseLowercase(StringPiece16 input); |
| |
| // Constructs an invalid GUID. |
| GUID(); |
| |
| GUID(const GUID& other); |
| GUID& operator=(const GUID& other); |
| GUID(GUID&& other); |
| GUID& operator=(GUID&& other); |
| |
| bool is_valid() const { return !lowercase_.empty(); } |
| |
| // Returns the GUID 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::GUID changes, |
| // this will be a non-trivial converter. See the TODO above `lowercase_` for |
| // more context. |
| const std::string& AsLowercaseString() const; |
| |
| // Invalid GUIDs are equal. |
| bool operator==(const GUID& other) const; |
| bool operator!=(const GUID& other) const; |
| bool operator<(const GUID& other) const; |
| bool operator<=(const GUID& other) const; |
| bool operator>(const GUID& other) const; |
| bool operator>=(const GUID& other) const; |
| |
| private: |
| static GUID FormatRandomDataAsV4Impl( |
| base::span<const uint8_t, kGuidV4InputLength> input); |
| |
| // TODO(crbug.com/1026195): Consider using a different internal type. |
| // Most existing representations of GUIDs in the codebase use std::string, |
| // so matching the internal type will avoid inefficient string conversions |
| // during the migration to base::GUID. |
| // |
| // The lowercase form of the GUID. Empty for invalid GUIDs. |
| 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 GUIDHash { |
| size_t operator()(const GUID& guid) const { |
| // TODO(crbug.com/1026195): Avoid converting to string to take the hash when |
| // the internal type is migrated to a non-string type. |
| return FastHash(guid.AsLowercaseString()); |
| } |
| }; |
| |
| // Stream operator so GUID objects can be used in logging statements. |
| BASE_EXPORT std::ostream& operator<<(std::ostream& out, const GUID& guid); |
| |
| } // namespace base |
| |
| #endif // BASE_GUID_H_ |