Export of internal Abseil changes

--
8726480d631a3736347f542dab5628d5e2ace3c1 by Mark Barolak <mbar@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 323414814

--
abc4a382a29fb857432e0e13a8c21ebe808f9828 by Abseil Team <absl-team@google.com>:

Fix buffer overflow when the result of demangling doesn't fit.

PiperOrigin-RevId: 323392968

--
7ed3e514519a971322d0a3333c7e85ed1f2a5f71 by Gennadiy Rozental <rogeeff@google.com>:

Move ABSL_DEPRECATED and ABSL_FALLTHROUGH_INTENDED from base.h into attribute.h.

PiperOrigin-RevId: 323137526

--
fc0afdb0792d565065d25feb9680972218355f90 by Xiaoyi Zhang <zhangxy@google.com>:

Add documentation for `absl::StatusCode`.

PiperOrigin-RevId: 323065623
GitOrigin-RevId: 8726480d631a3736347f542dab5628d5e2ace3c1
Change-Id: I9d39650e49ff265cd2dafee302013694e97c813f

5 files changed, 204 insertions, 86 deletions

diff --git a/absl/base/attributes.h b/absl/base/attributes.h
index c4fd81b..2cf4b1e 100644
--- a/absl/base/attributes.h
+++ b/absl/base/attributes.h
@@ -594,6 +594,85 @@
 #define ABSL_ATTRIBUTE_FUNC_ALIGN(bytes)
 #endif
 
+// ABSL_FALLTHROUGH_INTENDED
+//
+// Annotates implicit fall-through between switch labels, allowing a case to
+// indicate intentional fallthrough and turn off warnings about any lack of a
+// `break` statement. The ABSL_FALLTHROUGH_INTENDED macro should be followed by
+// a semicolon and can be used in most places where `break` can, provided that
+// no statements exist between it and the next switch label.
+//
+// Example:
+//
+//  switch (x) {
+//    case 40:
+//    case 41:
+//      if (truth_is_out_there) {
+//        ++x;
+//        ABSL_FALLTHROUGH_INTENDED;  // Use instead of/along with annotations
+//                                    // in comments
+//      } else {
+//        return x;
+//      }
+//    case 42:
+//      ...
+//
+// Notes: when compiled with clang in C++11 mode, the ABSL_FALLTHROUGH_INTENDED
+// macro is expanded to the [[clang::fallthrough]] attribute, which is analysed
+// when  performing switch labels fall-through diagnostic
+// (`-Wimplicit-fallthrough`). See clang documentation on language extensions
+// for details:
+// https://clang.llvm.org/docs/AttributeReference.html#fallthrough-clang-fallthrough
+//
+// When used with unsupported compilers, the ABSL_FALLTHROUGH_INTENDED macro
+// has no effect on diagnostics. In any case this macro has no effect on runtime
+// behavior and performance of code.
+#ifdef ABSL_FALLTHROUGH_INTENDED
+#error "ABSL_FALLTHROUGH_INTENDED should not be defined."
+#endif
+
+// TODO(zhangxy): Use c++17 standard [[fallthrough]] macro, when supported.
+#if defined(__clang__) && defined(__has_warning)
+#if __has_feature(cxx_attributes) && __has_warning("-Wimplicit-fallthrough")
+#define ABSL_FALLTHROUGH_INTENDED [[clang::fallthrough]]
+#endif
+#elif defined(__GNUC__) && __GNUC__ >= 7
+#define ABSL_FALLTHROUGH_INTENDED [[gnu::fallthrough]]
+#endif
+
+#ifndef ABSL_FALLTHROUGH_INTENDED
+#define ABSL_FALLTHROUGH_INTENDED \
+  do {                            \
+  } while (0)
+#endif
+
+// ABSL_DEPRECATED()
+//
+// Marks a deprecated class, struct, enum, function, method and variable
+// declarations. The macro argument is used as a custom diagnostic message (e.g.
+// suggestion of a better alternative).
+//
+// Examples:
+//
+//   class ABSL_DEPRECATED("Use Bar instead") Foo {...};
+//
+//   ABSL_DEPRECATED("Use Baz() instead") void Bar() {...}
+//
+//   template <typename T>
+//   ABSL_DEPRECATED("Use DoThat() instead")
+//   void DoThis();
+//
+// Every usage of a deprecated entity will trigger a warning when compiled with
+// clang's `-Wdeprecated-declarations` option. This option is turned off by
+// default, but the warnings will be reported by clang-tidy.
+#if defined(__clang__) && __cplusplus >= 201103L
+#define ABSL_DEPRECATED(message) __attribute__((deprecated(message)))
+#endif
+
+#ifndef ABSL_DEPRECATED
+#define ABSL_DEPRECATED(message)
+#endif
+
 // ABSL_CONST_INIT
 //
 // A variable declaration annotated with the `ABSL_CONST_INIT` attribute will
diff --git a/absl/base/macros.h b/absl/base/macros.h
index ea1da65..02dd9ff 100644
--- a/absl/base/macros.h
+++ b/absl/base/macros.h
@@ -55,85 +55,6 @@ auto ArraySizeHelper(const T (&array)[N]) -> char (&)[N];
 ABSL_NAMESPACE_END
 }  // namespace absl
 
-// ABSL_FALLTHROUGH_INTENDED
-//
-// Annotates implicit fall-through between switch labels, allowing a case to
-// indicate intentional fallthrough and turn off warnings about any lack of a
-// `break` statement. The ABSL_FALLTHROUGH_INTENDED macro should be followed by
-// a semicolon and can be used in most places where `break` can, provided that
-// no statements exist between it and the next switch label.
-//
-// Example:
-//
-//  switch (x) {
-//    case 40:
-//    case 41:
-//      if (truth_is_out_there) {
-//        ++x;
-//        ABSL_FALLTHROUGH_INTENDED;  // Use instead of/along with annotations
-//                                    // in comments
-//      } else {
-//        return x;
-//      }
-//    case 42:
-//      ...
-//
-// Notes: when compiled with clang in C++11 mode, the ABSL_FALLTHROUGH_INTENDED
-// macro is expanded to the [[clang::fallthrough]] attribute, which is analysed
-// when  performing switch labels fall-through diagnostic
-// (`-Wimplicit-fallthrough`). See clang documentation on language extensions
-// for details:
-// https://clang.llvm.org/docs/AttributeReference.html#fallthrough-clang-fallthrough
-//
-// When used with unsupported compilers, the ABSL_FALLTHROUGH_INTENDED macro
-// has no effect on diagnostics. In any case this macro has no effect on runtime
-// behavior and performance of code.
-#ifdef ABSL_FALLTHROUGH_INTENDED
-#error "ABSL_FALLTHROUGH_INTENDED should not be defined."
-#endif
-
-// TODO(zhangxy): Use c++17 standard [[fallthrough]] macro, when supported.
-#if defined(__clang__) && defined(__has_warning)
-#if __has_feature(cxx_attributes) && __has_warning("-Wimplicit-fallthrough")
-#define ABSL_FALLTHROUGH_INTENDED [[clang::fallthrough]]
-#endif
-#elif defined(__GNUC__) && __GNUC__ >= 7
-#define ABSL_FALLTHROUGH_INTENDED [[gnu::fallthrough]]
-#endif
-
-#ifndef ABSL_FALLTHROUGH_INTENDED
-#define ABSL_FALLTHROUGH_INTENDED \
-  do {                            \
-  } while (0)
-#endif
-
-// ABSL_DEPRECATED()
-//
-// Marks a deprecated class, struct, enum, function, method and variable
-// declarations. The macro argument is used as a custom diagnostic message (e.g.
-// suggestion of a better alternative).
-//
-// Examples:
-//
-//   class ABSL_DEPRECATED("Use Bar instead") Foo {...};
-//
-//   ABSL_DEPRECATED("Use Baz() instead") void Bar() {...}
-//
-//   template <typename T>
-//   ABSL_DEPRECATED("Use DoThat() instead")
-//   void DoThis();
-//
-// Every usage of a deprecated entity will trigger a warning when compiled with
-// clang's `-Wdeprecated-declarations` option. This option is turned off by
-// default, but the warnings will be reported by clang-tidy.
-#if defined(__clang__) && __cplusplus >= 201103L
-#define ABSL_DEPRECATED(message) __attribute__((deprecated(message)))
-#endif
-
-#ifndef ABSL_DEPRECATED
-#define ABSL_DEPRECATED(message)
-#endif
-
 // ABSL_BAD_CALL_IF()
 //
 // Used on a function overload to trap bad calls: any call that matches the
diff --git a/absl/debugging/internal/demangle.cc b/absl/debugging/internal/demangle.cc
index fc262e5..5f54ef3 100644
--- a/absl/debugging/internal/demangle.cc
+++ b/absl/debugging/internal/demangle.cc
@@ -409,6 +409,7 @@ static bool IsFunctionCloneSuffix(const char *str) {
 
 static bool EndsWith(State *state, const char chr) {
   return state->parse_state.out_cur_idx > 0 &&
+         state->parse_state.out_cur_idx < state->out_end_idx &&
          chr == state->out[state->parse_state.out_cur_idx - 1];
 }
 
@@ -421,8 +422,10 @@ static void MaybeAppendWithLength(State *state, const char *const str,
     if (str[0] == '<' && EndsWith(state, '<')) {
       Append(state, " ", 1);
     }
-    // Remember the last identifier name for ctors/dtors.
-    if (IsAlpha(str[0]) || str[0] == '_') {
+    // Remember the last identifier name for ctors/dtors,
+    // but only if we haven't yet overflown the buffer.
+    if (state->parse_state.out_cur_idx < state->out_end_idx &&
+        (IsAlpha(str[0]) || str[0] == '_')) {
       state->parse_state.prev_name_idx = state->parse_state.out_cur_idx;
       state->parse_state.prev_name_length = length;
     }
diff --git a/absl/status/status.h b/absl/status/status.h
index 967e606..4253062 100644
--- a/absl/status/status.h
+++ b/absl/status/status.h
@@ -24,24 +24,137 @@
 namespace absl {
 ABSL_NAMESPACE_BEGIN
 
+// Sometimes multiple error codes may apply.  Services should return
+// the most specific error code that applies.  For example, prefer
+// `kOutOfRange` over `kFailedPrecondition` if both codes apply.
+// Similarly prefer `kNotFound` or `kAlreadyExists` over `kFailedPrecondition`.
 enum class StatusCode : int {
+  // Not an error; returned on success
   kOk = 0,
+
+  // The operation was cancelled, typically by the caller.
   kCancelled = 1,
+
+  // Unknown error. For example, errors raised by APIs that do not return
+  // enough error information may be converted to this error.
   kUnknown = 2,
+
+  // The client specified an invalid argument. Note that this differs
+  // from `kFailedPrecondition`. `kInvalidArgument` indicates arguments
+  // that are problematic regardless of the state of the system
+  // (such as a malformed file name).
   kInvalidArgument = 3,
+
+  // The deadline expired before the operation could complete. For operations
+  // that change the state of the system, this error may be returned
+  // even if the operation has completed successfully. For example, a
+  // successful response from a server could have been delayed long
+  // enough for the deadline to expire.
   kDeadlineExceeded = 4,
+
+  // Some requested entity (such as file or directory) was not found.
+  //
+  // Note to server developers: if a request is denied for an entire class
+  // of users, such as gradual feature rollout or undocumented whitelist,
+  // `kNotFound` may be used. If a request is denied for some users within
+  // a class of users, such as user-based access control, `kPermissionDenied`
+  // must be used.
   kNotFound = 5,
+
+  // The entity that a client attempted to create (such as file or directory)
+  // already exists.
   kAlreadyExists = 6,
+
+  // The caller does not have permission to execute the specified
+  // operation. `kPermissionDenied` must not be used for rejections
+  // caused by exhausting some resource (use `kResourceExhausted`
+  // instead for those errors). `kPermissionDenied` must not be
+  // used if the caller can not be identified (use `kUnauthenticated`
+  // instead for those errors). This error code does not imply the
+  // request is valid or the requested entity exists or satisfies
+  // other pre-conditions.
   kPermissionDenied = 7,
+
+  // Some resource has been exhausted, perhaps a per-user quota, or
+  // perhaps the entire file system is out of space.
   kResourceExhausted = 8,
+
+  // The operation was rejected because the system is not in a state
+  // required for the operation's execution. For example, the directory
+  // to be deleted is non-empty, an rmdir operation is applied to
+  // a non-directory, etc.
+  //
+  // A litmus test that may help a service implementer in deciding
+  // between `kFailedPrecondition`, `kAborted`, and `kUnavailable`:
+  //  (a) Use `kUnavailable` if the client can retry just the failing call.
+  //  (b) Use `kAborted` if the client should retry at a higher-level
+  //      (such as when a client-specified test-and-set fails, indicating the
+  //      client should restart a read-modify-write sequence).
+  //  (c) Use `kFailedPrecondition` if the client should not retry until
+  //      the system state has been explicitly fixed. For example, if an "rmdir"
+  //      fails because the directory is non-empty, `kFailedPrecondition`
+  //      should be returned since the client should not retry unless
+  //      the files are deleted from the directory.
   kFailedPrecondition = 9,
+
+  // The operation was aborted, typically due to a concurrency issue such as
+  // a sequencer check failure or transaction abort.
+  //
+  // See litmus test above for deciding between `kFailedPrecondition`,
+  // `kAborted`, and `kUnavailable`.
   kAborted = 10,
+
+  // The operation was attempted past the valid range, such as seeking or
+  // reading past end-of-file.
+  //
+  // Unlike `kInvalidArgument`, this error indicates a problem that may
+  // be fixed if the system state changes. For example, a 32-bit file
+  // system will generate `kInvalidArgument` if asked to read at an
+  // offset that is not in the range [0,2^32-1], but it will generate
+  // `kOutOfRange` if asked to read from an offset past the current
+  // file size.
+  //
+  // There is a fair bit of overlap between `kFailedPrecondition` and
+  // `kOutOfRange`.  We recommend using `kOutOfRange` (the more specific
+  // error) when it applies so that callers who are iterating through
+  // a space can easily look for an `kOutOfRange` error to detect when
+  // they are done.
   kOutOfRange = 11,
+
+  // The operation is not implemented or is not supported/enabled in this
+  // service.
   kUnimplemented = 12,
+
+  // Internal errors. This means that some invariants expected by the
+  // underlying system have been broken. This error code is reserved
+  // for serious errors.
   kInternal = 13,
+
+  // The service is currently unavailable. This is most likely a
+  // transient condition, which can be corrected by retrying with
+  // a backoff. Note that it is not always safe to retry
+  // non-idempotent operations.
+  //
+  // See litmus test above for deciding between `kFailedPrecondition`,
+  // `kAborted`, and `kUnavailable`.
   kUnavailable = 14,
+
+  // Unrecoverable data loss or corruption.
   kDataLoss = 15,
+
+  // The request does not have valid authentication credentials for the
+  // operation.
   kUnauthenticated = 16,
+
+  // An extra enum entry to prevent people from writing code that
+  // fails to compile when a new code is added.
+  //
+  // Nobody should ever reference this enumeration entry. In particular,
+  // if you write C++ code that switches on this enumeration, add a default:
+  // case instead of a case that mentions this enumeration entry.
+  //
+  // Nobody should rely on the value (currently 20) listed here.  It
+  // may change in the future.
   kDoNotUseReservedForFutureExpansionUseDefaultInSwitchInstead_ = 20
 };
 
diff --git a/absl/time/internal/cctz/src/time_zone_info.cc b/absl/time/internal/cctz/src/time_zone_info.cc
index 7ccda11..c7bf044 100644
--- a/absl/time/internal/cctz/src/time_zone_info.cc
+++ b/absl/time/internal/cctz/src/time_zone_info.cc
@@ -365,8 +365,10 @@ bool TimeZoneInfo::ExtendTransitions() {
   std::int_fast64_t jan1_time = jan1 - civil_second();
   int jan1_weekday = ToPosixWeekday(get_weekday(jan1));
 
-  Transition dst = {0, dst_ti, civil_second(), civil_second()};
-  Transition std = {0, std_ti, civil_second(), civil_second()};
+  Transition dst = {0, static_cast<uint_least8_t>(dst_ti), civil_second(),
+                    civil_second()};
+  Transition std = {0, static_cast<uint_least8_t>(std_ti), civil_second(),
+                    civil_second()};
   for (const year_t limit = last_year_ + 400;; ++last_year_) {
     auto dst_trans_off = TransOffset(leap_year, jan1_weekday, posix.dst_start);
     auto std_trans_off = TransOffset(leap_year, jan1_weekday, posix.dst_end);
@@ -725,9 +727,9 @@ bool TimeZoneInfo::Load(const std::string& name) {
 
   // Find and use a ZoneInfoSource to load the named zone.
   auto zip = cctz_extension::zone_info_source_factory(
-      name, [](const std::string& name) -> std::unique_ptr<ZoneInfoSource> {
-        if (auto zip = FileZoneInfoSource::Open(name)) return zip;
-        if (auto zip = AndroidZoneInfoSource::Open(name)) return zip;
+      name, [](const std::string& n) -> std::unique_ptr<ZoneInfoSource> {
+        if (auto z = FileZoneInfoSource::Open(n)) return z;
+        if (auto z = AndroidZoneInfoSource::Open(n)) return z;
         return nullptr;
       });
   return zip != nullptr && Load(zip.get());