Change absl::Status implementation to be amenable to [[clang:trivial_abi]] annotation.

This moves the implementation of most methods from absl::Status to absl::status_internal::StatusRep, and ensures that no calls to absl::Status methods are in a cc file.

Stub implementations checking only inlined rep properties and calling no-op (RepToPointer) or out of line methods exist in status.h

PiperOrigin-RevId: 566187430
Change-Id: I356ec29c0970ffe82eac2a5d98850e647fcd5ea5

1 files changed, 48 insertions, 10 deletions

diff --git a/absl/status/internal/status_internal.h b/absl/status/internal/status_internal.h
index f22c611d..a445ce37 100644
--- a/absl/status/internal/status_internal.h
+++ b/absl/status/internal/status_internal.h
@@ -14,13 +14,18 @@
 #ifndef ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
 #define ABSL_STATUS_INTERNAL_STATUS_INTERNAL_H_
 
+#include <atomic>
+#include <cstdint>
 #include <memory>
 #include <string>
 #include <utility>
 
 #include "absl/base/attributes.h"
+#include "absl/base/config.h"
 #include "absl/container/inlined_vector.h"
 #include "absl/strings/cord.h"
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
 
 #ifndef SWIG
 // Disabled for SWIG as it doesn't parse attributes correctly.
@@ -44,6 +49,7 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 
 enum class StatusCode : int;
+enum class StatusToStringMode : int;
 
 namespace status_internal {
 
@@ -56,22 +62,54 @@ struct Payload {
 using Payloads = absl::InlinedVector<Payload, 1>;
 
 // Reference-counted representation of Status data.
-struct StatusRep {
+class StatusRep {
+ public:
   StatusRep(absl::StatusCode code_arg, absl::string_view message_arg,
             std::unique_ptr<status_internal::Payloads> payloads_arg)
-      : ref(int32_t{1}),
-        code(code_arg),
-        message(message_arg),
-        payloads(std::move(payloads_arg)) {}
-
-  std::atomic<int32_t> ref;
-  absl::StatusCode code;
+      : ref_(int32_t{1}),
+        code_(code_arg),
+        message_(message_arg),
+        payloads_(std::move(payloads_arg)) {}
+
+  absl::StatusCode code() const { return code_; }
+  const std::string& message() const { return message_; }
+
+  // Ref and unref are const to allow access through a const pointer, and are
+  // used during copying operations.
+  void Ref() const { ref_.fetch_add(1, std::memory_order_relaxed); }
+  void Unref() const;
+
+  // Payload methods correspond to the same methods in absl::Status.
+  absl::optional<absl::Cord> GetPayload(absl::string_view type_url) const;
+  void SetPayload(absl::string_view type_url, absl::Cord payload);
+  struct EraseResult {
+    bool erased;
+    uintptr_t new_rep;
+  };
+  EraseResult ErasePayload(absl::string_view type_url);
+  void ForEachPayload(
+      absl::FunctionRef<void(absl::string_view, const absl::Cord&)> visitor)
+      const;
+
+  std::string ToString(StatusToStringMode mode) const;
+
+  bool operator==(const StatusRep& other) const;
+  bool operator!=(const StatusRep& other) const { return !(*this == other); }
+
+  // Returns an equivalent heap allocated StatusRep with refcount 1.
+  //
+  // `this` is not safe to be used after calling as it may have been deleted.
+  StatusRep* CloneAndUnref() const;
+
+ private:
+  mutable std::atomic<int32_t> ref_;
+  absl::StatusCode code_;
 
   // As an internal implementation detail, we guarantee that if status.message()
   // is non-empty, then the resulting string_view is null terminated.
   // This is required to implement 'StatusMessageAsCStr(...)'
-  std::string message;
-  std::unique_ptr<status_internal::Payloads> payloads;
+  std::string message_;
+  std::unique_ptr<status_internal::Payloads> payloads_;
 };
 
 absl::StatusCode MapToLocalCode(int value);