Export of internal Abseil changes

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0c8282d75798c77733eee6167870bcc6acc0bfc1 by Evan Brown <ezb@google.com>:

Provide mutable access to the key in node handles using std::launder when compiled with C++17 or later.

Also, document why we can't provide mutable access to the key without C++17.

Note: we use Policy::mutable_key() because btree already uses Policy::key() internally to get const key access, and we want to avoid calling std::launder unless we need mutable access to the key.
PiperOrigin-RevId: 326519000

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8018d0c3044400f0a731b0d2d00b606742c98818 by Xiaoyi Zhang <zhangxy@google.com>:

Move `Status` internal symbols from the public header into an internal header file.

PiperOrigin-RevId: 326471847

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87a7644864ba7c003b0611898aaba1b71c840376 by Abseil Team <absl-team@google.com>:

Avoid a costly divide (the division accounts for 10% of the time spent in the function).

When the division is signed, the compiler has to generate a div. When it is unsigned, it can generate a shift: https://godbolt.org/z/vGfTv4. As per the test above the div, we know that the value is unsigned.

PiperOrigin-RevId: 326453275
GitOrigin-RevId: 0c8282d75798c77733eee6167870bcc6acc0bfc1
Change-Id: I0a953558358055ab3dc6a533d8930698509b1195

4 files changed, 54 insertions, 21 deletions

diff --git a/absl/status/BUILD.bazel b/absl/status/BUILD.bazel
index d164252d..c4c5e497 100644
--- a/absl/status/BUILD.bazel
+++ b/absl/status/BUILD.bazel
@@ -31,6 +31,7 @@ licenses(["notice"])  # Apache 2.0
 cc_library(
     name = "status",
     srcs = [
+        "internal/status_internal.h",
         "status.cc",
         "status_payload_printer.cc",
     ],
diff --git a/absl/status/CMakeLists.txt b/absl/status/CMakeLists.txt
index c041d695..b48989d1 100644
--- a/absl/status/CMakeLists.txt
+++ b/absl/status/CMakeLists.txt
@@ -19,6 +19,7 @@ absl_cc_library(
   HDRS
     "status.h"
   SRCS
+    "internal/status_internal.h"
     "status.cc"
     "status_payload_printer.h"
     "status_payload_printer.cc"
diff --git a/absl/status/internal/status_internal.h b/absl/status/internal/status_internal.h
new file mode 100644
index 00000000..1f82b8e4
--- /dev/null
+++ b/absl/status/internal/status_internal.h
@@ -0,0 +1,51 @@
+// Copyright 2019 The Abseil Authors.
+//
+// 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 ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
+#define ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
+
+#include <string>
+
+#include "absl/container/inlined_vector.h"
+#include "absl/strings/cord.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+enum class StatusCode : int;
+
+namespace status_internal {
+
+// Container for status payloads.
+struct Payload {
+  std::string type_url;
+  absl::Cord payload;
+};
+
+using Payloads = absl::InlinedVector<Payload, 1>;
+
+// Reference-counted representation of Status data.
+struct StatusRep {
+  std::atomic<int32_t> ref;
+  absl::StatusCode code;
+  std::string message;
+  std::unique_ptr<status_internal::Payloads> payloads;
+};
+
+absl::StatusCode MapToLocalCode(int value);
+}  // namespace status_internal
+
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
diff --git a/absl/status/status.h b/absl/status/status.h
index 42530621..8097b05a 100644
--- a/absl/status/status.h
+++ b/absl/status/status.h
@@ -18,6 +18,7 @@
 #include <string>
 
 #include "absl/container/inlined_vector.h"
+#include "absl/status/internal/status_internal.h"
 #include "absl/strings/cord.h"
 #include "absl/types/optional.h"
 
@@ -164,27 +165,6 @@ std::string StatusCodeToString(StatusCode code);
 // Streams StatusCodeToString(code) to `os`.
 std::ostream& operator<<(std::ostream& os, StatusCode code);
 
-namespace status_internal {
-
-// Container for status payloads.
-struct Payload {
-  std::string type_url;
-  absl::Cord payload;
-};
-
-using Payloads = absl::InlinedVector<Payload, 1>;
-
-// Reference-counted representation of Status data.
-struct StatusRep {
-  std::atomic<int32_t> ref;
-  absl::StatusCode code;
-  std::string message;
-  std::unique_ptr<status_internal::Payloads> payloads;
-};
-
-absl::StatusCode MapToLocalCode(int value);
-}  // namespace status_internal
-
 class ABSL_MUST_USE_RESULT Status final {
  public:
   // Creates an OK status with no message or payload.