ArenaBytes

common/BUILD

@@ -960,3 +960,49 @@ cc_test(
         "@com_google_protobuf//:protobuf",
     ],
 )
+
+cc_library(
+    name = "arena_bytes",
+    hdrs = ["arena_bytes.h"],
+    deps = [
+        "@com_google_absl//absl/base",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/base:nullability",
+        "@com_google_absl//absl/strings:string_view",
+    ],
+)
+
+cc_test(
+    name = "arena_bytes_test",
+    srcs = ["arena_bytes_test.cc"],
+    deps = [
+        ":arena_bytes",
+        "//internal:testing",
+        "@com_google_absl//absl/hash",
+        "@com_google_absl//absl/hash:hash_testing",
+        "@com_google_absl//absl/strings:string_view",
+    ],
+)
+
+cc_library(
+    name = "arena_bytes_pool",
+    hdrs = ["arena_bytes_pool.h"],
+    deps = [
+        ":arena_bytes",
+        "//internal:string_pool",
+        "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/base:nullability",
+        "@com_google_absl//absl/strings:string_view",
+        "@com_google_protobuf//:protobuf",
+    ],
+)
+
+cc_test(
+    name = "arena_bytes_pool_test",
+    srcs = ["arena_bytes_pool_test.cc"],
+    deps = [
+        ":arena_bytes_pool",
+        "//internal:testing",
+        "@com_google_protobuf//:protobuf",
+    ],
+)

common/arena_bytes.h

@@ -0,0 +1,252 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef THIRD_PARTY_CEL_CPP_COMMON_ARENA_BYTES_H_
+#define THIRD_PARTY_CEL_CPP_COMMON_ARENA_BYTES_H_
+
+#include <cstddef>
+#include <iterator>
+#include <string>
+#include <type_traits>
+
+#include "absl/base/attributes.h"
+#include "absl/base/casts.h"
+#include "absl/base/macros.h"
+#include "absl/base/nullability.h"
+#include "absl/strings/string_view.h"
+
+namespace cel {
+
+class ArenaBytesPool;
+
+// Bug in current Abseil LTS. Fixed in
+// https://github.com/abseil/abseil-cpp/commit/fd7713cb9a97c49096211ff40de280b6cebbb21c
+// which is not yet in an LTS.
+#if defined(__clang__) && (!defined(__clang_major__) || __clang_major__ >= 13)
+#define CEL_ATTRIBUTE_ARENA_BYTES_VIEW ABSL_ATTRIBUTE_VIEW
+#else
+#define CEL_ATTRIBUTE_ARENA_BYTES_VIEW
+#endif
+
+// `ArenaBytes` is a read-only string which is either backed by a static string
+// literal or owned by the `ArenaBytesPool` that created it. It is compatible
+// with `absl::string_view` and is implicitly convertible to it.
+class CEL_ATTRIBUTE_ARENA_BYTES_VIEW ArenaBytes final {
+ private:
+  template <size_t N>
+  static constexpr bool IsStringLiteral(const char (&string)[N]) {
+    static_assert(N > 0);
+    for (size_t i = 0; i < N - 1; ++i) {
+      if (string[i] == '\0') {
+        return false;
+      }
+    }
+    return string[N - 1] == '\0';
+  }
+
+ public:
+  using traits_type = std::char_traits<char>;
+  using value_type = char;
+  using pointer = char*;
+  using const_pointer = const char*;
+  using reference = char&;
+  using const_reference = const char&;
+  using const_iterator = const_pointer;
+  using iterator = const_iterator;
+  using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+  using reverse_iterator = const_reverse_iterator;
+  using size_type = size_t;
+  using difference_type = ptrdiff_t;
+
+  using absl_internal_is_view = std::true_type;
+
+  template <size_t N>
+  static constexpr ArenaBytes Static(const char (&bytes)[N])
+#if ABSL_HAVE_ATTRIBUTE(enable_if)
+      __attribute__((enable_if(IsStringLiteral(bytes),
+                               "chosen when 'bytes' is a string literal")))
+#endif
+  {
+    static_assert(N > 0);
+    static_assert(N - 1 <= absl::string_view().max_size());
+    return ArenaBytes(bytes);
+  }
+
+  ArenaBytes() = default;
+  ArenaBytes(const ArenaBytes&) = default;
+  ArenaBytes& operator=(const ArenaBytes&) = default;
+
+  constexpr size_type size() const { return size_; }
+
+  constexpr bool empty() const { return size() == 0; }
+
+  constexpr size_type max_size() const {
+    return absl::string_view().max_size();
+  }
+
+  constexpr absl::Nonnull<const_pointer> data() const { return data_; }
+
+  constexpr const_reference front() const {
+    ABSL_ASSERT(!empty());
+    return data()[0];
+  }
+
+  constexpr const_reference back() const {
+    ABSL_ASSERT(!empty());
+    return data()[size() - 1];
+  }
+
+  constexpr const_reference operator[](size_type index) const {
+    ABSL_ASSERT(index < size());
+    return data()[index];
+  }
+
+  constexpr void remove_prefix(size_type n) {
+    ABSL_ASSERT(n <= size());
+    data_ += n;
+    size_ -= n;
+  }
+
+  constexpr void remove_suffix(size_type n) {
+    ABSL_ASSERT(n <= size());
+    size_ -= n;
+  }
+
+  constexpr const_iterator begin() const { return data(); }
+
+  constexpr const_iterator cbegin() const { return begin(); }
+
+  constexpr const_iterator end() const { return data() + size(); }
+
+  constexpr const_iterator cend() const { return end(); }
+
+  constexpr const_reverse_iterator rbegin() const {
+    return std::make_reverse_iterator(end());
+  }
+
+  constexpr const_reverse_iterator crbegin() const { return rbegin(); }
+
+  constexpr const_reverse_iterator rend() const {
+    return std::make_reverse_iterator(begin());
+  }
+
+  constexpr const_reverse_iterator crend() const { return rend(); }
+
+  // NOLINTNEXTLINE(google-explicit-constructor)
+  constexpr operator absl::string_view() const {
+    return absl::string_view(data(), size());
+  }
+
+ private:
+  friend class ArenaBytesPool;
+
+  constexpr explicit ArenaBytes(absl::string_view value)
+      : data_(value.data()), size_(static_cast<size_type>(value.size())) {
+    ABSL_ASSERT(value.data() != nullptr);
+    ABSL_ASSERT(value.size() <= max_size());
+  }
+
+  absl::Nonnull<const char*> data_ = "";
+  size_type size_ = 0;
+};
+
+constexpr bool operator==(ArenaBytes lhs, ArenaBytes rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) ==
+         absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator==(ArenaBytes lhs, absl::string_view rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) == rhs;
+}
+
+constexpr bool operator==(absl::string_view lhs, ArenaBytes rhs) {
+  return lhs == absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator!=(ArenaBytes lhs, ArenaBytes rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) !=
+         absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator!=(ArenaBytes lhs, absl::string_view rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) != rhs;
+}
+
+constexpr bool operator!=(absl::string_view lhs, ArenaBytes rhs) {
+  return lhs != absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator<(ArenaBytes lhs, ArenaBytes rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) <
+         absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator<(ArenaBytes lhs, absl::string_view rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) < rhs;
+}
+
+constexpr bool operator<(absl::string_view lhs, ArenaBytes rhs) {
+  return lhs < absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator<=(ArenaBytes lhs, ArenaBytes rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) <=
+         absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator<=(ArenaBytes lhs, absl::string_view rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) <= rhs;
+}
+
+constexpr bool operator<=(absl::string_view lhs, ArenaBytes rhs) {
+  return lhs <= absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator>(ArenaBytes lhs, ArenaBytes rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) >
+         absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator>(ArenaBytes lhs, absl::string_view rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) > rhs;
+}
+
+constexpr bool operator>(absl::string_view lhs, ArenaBytes rhs) {
+  return lhs > absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator>=(ArenaBytes lhs, ArenaBytes rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) >=
+         absl::implicit_cast<absl::string_view>(rhs);
+}
+
+constexpr bool operator>=(ArenaBytes lhs, absl::string_view rhs) {
+  return absl::implicit_cast<absl::string_view>(lhs) >= rhs;
+}
+
+constexpr bool operator>=(absl::string_view lhs, ArenaBytes rhs) {
+  return lhs >= absl::implicit_cast<absl::string_view>(rhs);
+}
+
+template <typename H>
+H AbslHashValue(H state, ArenaBytes arena_string) {
+  return H::combine(std::move(state),
+                    absl::implicit_cast<absl::string_view>(arena_string));
+}
+
+#undef CEL_ATTRIBUTE_ARENA_BYTES_VIEW
+
+}  // namespace cel
+
+#endif  // THIRD_PARTY_CEL_CPP_COMMON_ARENA_BYTES_H_

common/arena_bytes_pool.h

@@ -0,0 +1,64 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef THIRD_PARTY_CEL_CPP_COMMON_ARENA_BYTES_POOL_H_
+#define THIRD_PARTY_CEL_CPP_COMMON_ARENA_BYTES_POOL_H_
+
+#include <memory>
+
+#include "absl/base/attributes.h"
+#include "absl/base/nullability.h"
+#include "absl/strings/string_view.h"
+#include "common/arena_bytes.h"
+#include "internal/string_pool.h"
+#include "google/protobuf/arena.h"
+
+namespace cel {
+
+class ArenaBytesPool;
+
+absl::Nonnull<std::unique_ptr<ArenaBytesPool>> NewArenaBytesPool(
+    absl::Nonnull<google::protobuf::Arena*> arena ABSL_ATTRIBUTE_LIFETIME_BOUND);
+
+class ArenaBytesPool final {
+ public:
+  ArenaBytesPool(const ArenaBytesPool&) = delete;
+  ArenaBytesPool(ArenaBytesPool&&) = delete;
+  ArenaBytesPool& operator=(const ArenaBytesPool&) = delete;
+  ArenaBytesPool& operator=(ArenaBytesPool&&) = delete;
+
+  ArenaBytes InternBytes(absl::string_view bytes) {
+    return ArenaBytes(strings_.InternString(bytes));
+  }
+
+  ArenaBytes InternBytes(ArenaBytes) = delete;
+
+ private:
+  friend absl::Nonnull<std::unique_ptr<ArenaBytesPool>> NewArenaBytesPool(
+      absl::Nonnull<google::protobuf::Arena*>);
+
+  explicit ArenaBytesPool(absl::Nonnull<google::protobuf::Arena*> arena)
+      : strings_(arena) {}
+
+  internal::StringPool strings_;
+};
+
+inline absl::Nonnull<std::unique_ptr<ArenaBytesPool>> NewArenaBytesPool(
+    absl::Nonnull<google::protobuf::Arena*> arena ABSL_ATTRIBUTE_LIFETIME_BOUND) {
+  return std::unique_ptr<ArenaBytesPool>(new ArenaBytesPool(arena));
+}
+
+}  // namespace cel
+
+#endif  // THIRD_PARTY_CEL_CPP_COMMON_ARENA_BYTES_POOL_H_