Export of internal Abseil changes

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93c607726d663800b4bfa472cba043fd3f5d0e97 by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 389158822

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55b3bb50bbc168567c6ba25d07df2c2c39e864af by Martijn Vels <mvels@google.com>:

Change CordRepRing alternative implementation to CordRepBtree alternative.

This changes makes CordRepBtree (BTREE) the alternative to CordRepConcat (CONCAT) trees, enabled through the internal / experimental 'cord_btree_enabled' latch.

PiperOrigin-RevId: 389030571

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d6fc346143606c096bca8eb5029e4c429ac6e305 by Todd Lipcon <tlipcon@google.com>:

Fix a small typo in SequenceLock doc comment

PiperOrigin-RevId: 388972936

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e46f9245dce8b4150e3ca2664e0cf42b75f90a83 by Martijn Vels <mvels@google.com>:

Add 'shallow' validation mode to CordRepBtree which will be the default for internal assertions.

PiperOrigin-RevId: 388753606

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b5e74f163b490beb006f848ace67bb650433fe13 by Martijn Vels <mvels@google.com>:

Add btree statistics to CordzInfo, and reduce rounding errors

PiperOrigin-RevId: 388715878

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105bcbf80de649937e693b29b18220f9e6841a51 by Evan Brown <ezb@google.com>:

Skip length checking when constructing absl::string_view from `const char*`.
The length check causes unnecessary code bloat.

PiperOrigin-RevId: 388271741

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bed595158f24839efe49c65ae483f797d79fe0ae by Derek Mauro <dmauro@google.com>:

Internal change

PiperOrigin-RevId: 387713428
GitOrigin-RevId: 93c607726d663800b4bfa472cba043fd3f5d0e97
Change-Id: I2a4840f5ffcd7f70b7d7d45cce66f23c42cf565f

1 files changed, 43 insertions, 0 deletions

diff --git a/absl/strings/internal/cord_rep_btree_test.cc b/absl/strings/internal/cord_rep_btree_test.cc
index 7a0b7811..073a7d45 100644
--- a/absl/strings/internal/cord_rep_btree_test.cc
+++ b/absl/strings/internal/cord_rep_btree_test.cc
@@ -24,6 +24,7 @@
 #include "gtest/gtest.h"
 #include "absl/base/config.h"
 #include "absl/base/internal/raw_logging.h"
+#include "absl/cleanup/cleanup.h"
 #include "absl/strings/internal/cord_internal.h"
 #include "absl/strings/internal/cord_rep_test_util.h"
 #include "absl/strings/str_cat.h"
@@ -1346,6 +1347,48 @@ TEST(CordRepBtreeTest, AssertValid) {
   CordRep::Unref(tree);
 }
 
+TEST(CordRepBtreeTest, CheckAssertValidShallowVsDeep) {
+  // Restore exhaustive validation on any exit.
+  const bool exhaustive_validation = cord_btree_exhaustive_validation.load();
+  auto cleanup = absl::MakeCleanup([exhaustive_validation] {
+    cord_btree_exhaustive_validation.store(exhaustive_validation);
+  });
+
+  // Create a tree of at least 2 levels, and mess with the original flat, which
+  // should go undetected in shallow mode as the flat is too far away, but
+  // should be detected in forced non-shallow mode.
+  CordRep* flat = MakeFlat("abc");
+  CordRepBtree* tree = CordRepBtree::Create(flat);
+  constexpr size_t max_cap = CordRepBtree::kMaxCapacity;
+  const size_t n = max_cap * max_cap * 2;
+  for (size_t i = 0; i < n; ++i) {
+    tree = CordRepBtree::Append(tree, MakeFlat("Hello world"));
+  }
+  flat->length = 100;
+
+  cord_btree_exhaustive_validation.store(false);
+  EXPECT_FALSE(CordRepBtree::IsValid(tree));
+  EXPECT_TRUE(CordRepBtree::IsValid(tree, true));
+  EXPECT_FALSE(CordRepBtree::IsValid(tree, false));
+  CordRepBtree::AssertValid(tree);
+  CordRepBtree::AssertValid(tree, true);
+#if defined(GTEST_HAS_DEATH_TEST)
+  EXPECT_DEBUG_DEATH(CordRepBtree::AssertValid(tree, false), ".*");
+#endif
+
+  cord_btree_exhaustive_validation.store(true);
+  EXPECT_FALSE(CordRepBtree::IsValid(tree));
+  EXPECT_FALSE(CordRepBtree::IsValid(tree, true));
+  EXPECT_FALSE(CordRepBtree::IsValid(tree, false));
+#if defined(GTEST_HAS_DEATH_TEST)
+  EXPECT_DEBUG_DEATH(CordRepBtree::AssertValid(tree), ".*");
+  EXPECT_DEBUG_DEATH(CordRepBtree::AssertValid(tree, true), ".*");
+#endif
+
+  flat->length = 3;
+  CordRep::Unref(tree);
+}
+
 }  // namespace
 }  // namespace cord_internal
 ABSL_NAMESPACE_END