Introduce Global() to replace NoDestructor.

`Global()` is simpler to use, especially if construction requires more code than
specifying constructor arguments: it does not require to name a variable and to
remember about `static`.

PiperOrigin-RevId: 631019686

python/riegeli/bytes/BUILD

@@ -16,7 +16,7 @@ cc_library(
         "//python/riegeli/base:utils",
         "//riegeli/base:arithmetic",
         "//riegeli/base:assert",
-        "//riegeli/base:no_destructor",
+        "//riegeli/base:global",
         "//riegeli/base:object",
         "//riegeli/base:types",
         "//riegeli/bytes:buffer_options",
@@ -41,7 +41,7 @@ cc_library(
         "//python/riegeli/base:utils",
         "//riegeli/base:arithmetic",
         "//riegeli/base:assert",
-        "//riegeli/base:no_destructor",
+        "//riegeli/base:global",
         "//riegeli/base:object",
         "//riegeli/base:types",
         "//riegeli/bytes:buffer_options",

python/riegeli/bytes/python_reader.cc

@@ -37,7 +37,7 @@
 #include "python/riegeli/base/utils.h"
 #include "riegeli/base/arithmetic.h"
 #include "riegeli/base/assert.h"
-#include "riegeli/base/no_destructor.h"
+#include "riegeli/base/global.h"
 #include "riegeli/base/types.h"
 #include "riegeli/bytes/buffered_reader.h"
 
@@ -52,9 +52,10 @@ PythonReader::PythonReader(PyObject* src, Options options)
   if (options.assumed_pos() != absl::nullopt) {
     set_limit_pos(*options.assumed_pos());
     // `supports_random_access_` is left as `false`.
-    static const NoDestructor<absl::Status> status(absl::UnimplementedError(
-        "PythonReader::Options::assumed_pos() excludes random access"));
-    random_access_status_ = *status;
+    random_access_status_ = Global([] {
+      return absl::UnimplementedError(
+          "PythonReader::Options::assumed_pos() excludes random access");
+    });
   } else {
     static constexpr Identifier id_seekable("seekable");
     const PythonPtr seekable_result(
@@ -71,9 +72,10 @@ PythonReader::PythonReader(PyObject* src, Options options)
     if (seekable_is_true == 0) {
       // Random access is not supported. Assume 0 as the initial position.
       // `supports_random_access_` is left as `false`.
-      static const NoDestructor<absl::Status> status(absl::UnimplementedError(
-          "seekable() is False which excludes random access"));
-      random_access_status_ = *status;
+      random_access_status_ = Global([] {
+        return absl::UnimplementedError(
+            "seekable() is False which excludes random access");
+      });
       return;
     }
     static constexpr Identifier id_tell("tell");

python/riegeli/bytes/python_writer.cc

@@ -36,7 +36,7 @@
 #include "python/riegeli/base/utils.h"
 #include "riegeli/base/arithmetic.h"
 #include "riegeli/base/assert.h"
-#include "riegeli/base/no_destructor.h"
+#include "riegeli/base/global.h"
 #include "riegeli/base/types.h"
 #include "riegeli/bytes/buffered_writer.h"
 
@@ -52,9 +52,10 @@ PythonWriter::PythonWriter(PyObject* dest, Options options)
   if (options.assumed_pos() != absl::nullopt) {
     set_start_pos(*options.assumed_pos());
     // `supports_random_access_` is left as `false`.
-    static const NoDestructor<absl::Status> status(absl::UnimplementedError(
-        "PythonWriter::Options::assumed_pos() excludes random access"));
-    random_access_status_ = *status;
+    random_access_status_ = Global([] {
+      return absl::UnimplementedError(
+          "PythonWriter::Options::assumed_pos() excludes random access");
+    });
   } else {
     static constexpr Identifier id_seekable("seekable");
     const PythonPtr seekable_result(
@@ -71,9 +72,10 @@ PythonWriter::PythonWriter(PyObject* dest, Options options)
     if (seekable_is_true == 0) {
       // Random access is not supported. Assume 0 as the initial position.
       // `supports_random_access_` is left as `false`.
-      static const NoDestructor<absl::Status> status(absl::UnimplementedError(
-          "seekable() is False which excludes random access"));
-      random_access_status_ = *status;
+      random_access_status_ = Global([] {
+        return absl::UnimplementedError(
+            "seekable() is False which excludes random access");
+      });
       return;
     }
     static constexpr Identifier id_tell("tell");

riegeli/base/BUILD

@@ -23,8 +23,9 @@ cc_library(
 )
 
 cc_library(
-    name = "no_destructor",
-    hdrs = ["no_destructor.h"],
+    name = "global",
+    hdrs = ["global.h"],
+    deps = ["@com_google_absl//absl/meta:type_traits"],
 )
 
 cc_library(
@@ -127,7 +128,7 @@ cc_library(
     hdrs = ["zeros.h"],
     deps = [
         ":cord_utils",
-        ":no_destructor",
+        ":global",
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/strings:cord",
     ],
@@ -410,10 +411,10 @@ cc_library(
         ":buffering",
         ":compare",
         ":cord_utils",
+        ":global",
         ":initializer",
         ":memory_estimator",
         ":new_aligned",
-        ":no_destructor",
         ":shared_buffer",
         ":shared_ptr",
         ":sized_shared_buffer",
@@ -466,7 +467,7 @@ cc_library(
     visibility = ["//riegeli:__subpackages__"],
     deps = [
         ":assert",
-        ":no_destructor",
+        ":global",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/functional:any_invocable",
         "@com_google_absl//absl/synchronization",
@@ -480,7 +481,7 @@ cc_library(
     hdrs = ["background_cleaning.h"],
     deps = [
         ":assert",
-        ":no_destructor",
+        ":global",
         ":parallelism",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/synchronization",
@@ -497,7 +498,7 @@ cc_library(
         ":assert",
         ":background_cleaning",
         ":compare",
-        ":no_destructor",
+        ":global",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:inlined_vector",

riegeli/base/background_cleaning.h

@@ -21,7 +21,7 @@
 #include "absl/synchronization/mutex.h"
 #include "absl/time/clock.h"
 #include "absl/time/time.h"
-#include "riegeli/base/no_destructor.h"
+#include "riegeli/base/global.h"
 
 namespace riegeli {
 
@@ -83,8 +83,7 @@ class BackgroundCleaner {
 
   // Returns a default global `BackgroundCleaner`.
   static BackgroundCleaner& global() {
-    static NoDestructor<BackgroundCleaner> kStaticBackgroundCleaner;
-    return *kStaticBackgroundCleaner;
+    return Global<BackgroundCleaner>([] {});
   }
 
   // Registers the cleanee, allowing `ScheduleCleaning()` calls.

riegeli/base/chain.cc

@@ -38,11 +38,11 @@
 #include "riegeli/base/buffering.h"
 #include "riegeli/base/compare.h"
 #include "riegeli/base/cord_utils.h"
+#include "riegeli/base/global.h"
 #include "riegeli/base/intrusive_shared_ptr.h"
 #include "riegeli/base/maker.h"
 #include "riegeli/base/memory_estimator.h"
 #include "riegeli/base/new_aligned.h"
-#include "riegeli/base/no_destructor.h"
 #include "riegeli/base/shared_buffer.h"
 #include "riegeli/base/sized_shared_buffer.h"
 #include "riegeli/base/string_utils.h"
@@ -2715,9 +2715,9 @@ Chain ChainOfZeros(size_t length) {
   const absl::string_view kArrayOfZeros = ArrayOfZeros();
   Chain result;
   while (length >= kArrayOfZeros.size()) {
-    static const NoDestructor<Chain> kChainBlockOfZeros(
-        Chain::FromExternal(riegeli::Maker<ZeroRef>(), kArrayOfZeros));
-    result.Append(*kChainBlockOfZeros);
+    result.Append(Global([] {
+      return Chain::FromExternal(riegeli::Maker<ZeroRef>(), ArrayOfZeros());
+    }));
     length -= kArrayOfZeros.size();
   }
   if (length > 0) {