-- d6748c733a70cd74ad9b76a0c9cd6b3fe2cecacf by Xiaoyi Zhang <zhangxy@google.com>: Remove empty block, to address alerts reported in https://github.com/abseil/abseil-cpp/issues/368. PiperOrigin-RevId: 265099887 -- 232e2036b5668d6d1296b881f9347756d84541ee by Derek Mauro <dmauro@google.com>: Make the Linux Bazel CI scripts test with the exception mode explicitly set. PiperOrigin-RevId: 265092105 -- 942a40696c2c9b833be03e92d22a6ede7bccb6d4 by Xiaoyi Zhang <zhangxy@google.com>: Import https://github.com/abseil/abseil-cpp/pull/372. Suppress the unused variable warning on GCC, i.e. "-Wunused-variable". PiperOrigin-RevId: 265063925 -- 7ef90796b52cbdc260afc77cf47206f9356471d0 by Xiaoyi Zhang <zhangxy@google.com>: Add quotes to `ABSL_COMMON_INCLUDE_DIRS` since it's a list and may contain a `;`. This addresses https://github.com/abseil/abseil-cpp/issues/373. PiperOrigin-RevId: 265059077 -- 43f3ae742e00b83672ad6c5bc5b17fdb8f9fe6fe by Gennadiy Rozental <rogeeff@google.com>: Internal re-organization PiperOrigin-RevId: 264913945 -- 6a2adf9c08ee1d98cc6b2855a676345c6495294a by Andy Soffer <asoffer@google.com>: Publicly expose type names for uniform interval tags as in, for example, absl::IntervalClosedClosedTag, and add equality comparison operators. PiperOrigin-RevId: 264861162 -- 3c90c6e05fd61d56b419cd2d39dab8f17b8711b8 by Abseil Team <absl-team@google.com>: Add validity check on returned frame pointer. PiperOrigin-RevId: 264858823 -- 2db87e0cfa0c6bea7ba81684b834cb8a73b7d748 by Gennadiy Rozental <rogeeff@google.com>: Add MUST_USE_RESULT attribute to absl::GetFlag to prevent accidental misuse. PiperOrigin-RevId: 264782762 GitOrigin-RevId: d6748c733a70cd74ad9b76a0c9cd6b3fe2cecacf Change-Id: I169e9c5358e4f63000c1255e806d26b8afecf5ffpull/376/head
Abseil Team
5 years ago
committed by
Xiaoyi Zhang
parent
0302d1e5fa
commit
2d2d7fbc28
24 changed files with 549 additions and 392 deletions
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//
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// Copyright 2019 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/flags/internal/flag.h" |
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#include "absl/synchronization/mutex.h" |
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namespace absl { |
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namespace flags_internal { |
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// If the flag has a mutation callback this function invokes it. While the
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// callback is being invoked the primary flag's mutex is unlocked and it is
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// re-locked back after call to callback is completed. Callback invocation is
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// guarded by flag's secondary mutex instead which prevents concurrent
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// callback invocation. Note that it is possible for other thread to grab the
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// primary lock and update flag's value at any time during the callback
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// invocation. This is by design. Callback can get a value of the flag if
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// necessary, but it might be different from the value initiated the callback
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// and it also can be different by the time the callback invocation is
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// completed. Requires that *primary_lock be held in exclusive mode; it may be
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// released and reacquired by the implementation.
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void InvokeCallback(absl::Mutex* primary_mu, absl::Mutex* callback_mu, |
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FlagCallback cb) EXCLUSIVE_LOCKS_REQUIRED(primary_mu) { |
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if (!cb) return; |
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// When executing the callback we need the primary flag's mutex to be
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// unlocked so that callback can retrieve the flag's value.
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primary_mu->Unlock(); |
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{ |
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absl::MutexLock lock(callback_mu); |
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cb(); |
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} |
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primary_mu->Lock(); |
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} |
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} // namespace flags_internal
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} // namespace absl
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