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- // Copyright (c) 2012 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef BASE_DEBUG_CRASH_LOGGING_H_
- #define BASE_DEBUG_CRASH_LOGGING_H_
- #include <stddef.h>
- #include <iosfwd>
- #include <memory>
- #include <type_traits>
- #include "base/base_export.h"
- #include "base/memory/raw_ptr.h"
- #include "base/strings/string_number_conversions.h"
- #include "base/strings/string_piece.h"
- namespace base {
- namespace debug {
- // A crash key is an annotation that is carried along with a crash report, to
- // provide additional debugging information beyond a stack trace. Crash keys
- // have a name and a string value.
- //
- // The preferred API is //components/crash/core/common:crash_key, however not
- // all clients can hold a direct dependency on that target. The API provided
- // in this file indirects the dependency and adds some convenience helpers that
- // make the API a bit less clunky.
- //
- // TODO(dcheng): Some of the nicer APIs should probably be upstreamed into
- // //components/crash.
- //
- // Preferred usage when a crash key value only needs to be set within a scope:
- //
- // SCOPED_CRASH_KEY_STRING32("category", "name", "value");
- // base::debug::DumpWithoutCrashing();
- //
- // If the crash key is pre-allocated elsewhere, but the value only needs to be
- // set within a scope:
- //
- // base::debug::ScopedCrashKeyString scoper(
- // GetCrashKeyForComponent(),
- // "value");
- //
- // Otherwise, if the crash key needs to persist (e.g. the actual crash dump is
- // triggered some time later asynchronously):
- //
- // static auto* const crash_key = base::debug::AllocateCrashKeyString(
- // "name", base::debug::CrashKeySize::Size32);
- // base::debug::SetCrashKeyString(crash_key);
- //
- // // Do other work before calling `base::debug::DumpWithoutCrashing()` later.
- //
- // ***WARNING***
- //
- // Do *not* write this:
- //
- // base::debug::SetCrashKeyString(
- // base::debug::AllocateCrashKeyString(
- // "name", base::debug::CrashKeySize::Size32),
- // "value");
- //
- // As this will leak a heap allocation every time the crash key is set!
- // The maximum length for a crash key's value must be one of the following
- // pre-determined values.
- enum class CrashKeySize {
- Size32 = 32,
- Size64 = 64,
- Size256 = 256,
- Size1024 = 1024,
- };
- struct CrashKeyString;
- // Allocates a new crash key with the specified |name| with storage for a
- // value up to length |size|. This will return null if the crash key system is
- // not initialized.
- //
- // Note: this internally allocates, so the returned pointer should always
- // be cached in a variable with static storage duration, e.g.:
- // static auto* const crash_key = base::debug::AllocateCrashKeyString(...);
- BASE_EXPORT CrashKeyString* AllocateCrashKeyString(const char name[],
- CrashKeySize size);
- // Stores |value| into the specified |crash_key|. The |crash_key| may be null
- // if AllocateCrashKeyString() returned null. If |value| is longer than the
- // size with which the key was allocated, it will be truncated.
- BASE_EXPORT void SetCrashKeyString(CrashKeyString* crash_key,
- base::StringPiece value);
- // Clears any value that was stored in |crash_key|. The |crash_key| may be
- // null.
- BASE_EXPORT void ClearCrashKeyString(CrashKeyString* crash_key);
- // Outputs current (i.e. allocated and non-empty) crash keys to `out`.
- BASE_EXPORT void OutputCrashKeysToStream(std::ostream& out);
- // A scoper that sets the specified key to value for the lifetime of the
- // object, and clears it on destruction.
- class BASE_EXPORT ScopedCrashKeyString {
- public:
- ScopedCrashKeyString(CrashKeyString* crash_key, base::StringPiece value);
- ScopedCrashKeyString(ScopedCrashKeyString&& other);
- ~ScopedCrashKeyString();
- // Disallow copy and assign.
- ScopedCrashKeyString(const ScopedCrashKeyString&) = delete;
- ScopedCrashKeyString& operator=(const ScopedCrashKeyString&) = delete;
- // Disallow move assign to keep the time at which the crash key is cleared
- // easy to reason about. Assigning over an existing instance would
- // automatically clear the key instead of at the destruction of the object.
- ScopedCrashKeyString& operator=(ScopedCrashKeyString&&) = delete;
- private:
- raw_ptr<CrashKeyString> crash_key_;
- };
- // Internal helpers for the SCOPED_CRASH_KEY_... helper macros defined below.
- //
- // The static_assert that checks the length of |key_name| is a compile-time
- // equivalent of the DCHECK in crash_reporter::internal::CrashKeyStringImpl::Set
- // that restricts the name of a crash key to 40 characters.
- #define SCOPED_CRASH_KEY_STRING_INTERNAL2(category, name, nonce, data, \
- key_size) \
- static_assert(::std::size(category "-" name) < 40, \
- "Crash key names must be shorter than 40 characters."); \
- ::base::debug::ScopedCrashKeyString scoped_crash_key_helper##nonce( \
- [] { \
- static auto* const key = ::base::debug::AllocateCrashKeyString( \
- category "-" name, key_size); \
- return key; \
- }(), \
- (data))
- // This indirection is needed to expand __COUNTER__.
- #define SCOPED_CRASH_KEY_STRING_INTERNAL(category, name, nonce, data, \
- key_size) \
- SCOPED_CRASH_KEY_STRING_INTERNAL2(category, name, nonce, data, key_size)
- // Helper macros for putting a local variable crash key on the stack before
- // causing a crash or calling CrashWithoutDumping(). `category` and `name`
- // should be string literals.
- //
- // SCOPED_CRASH_KEY_STRING32("MyCategory", "key_name", "value");
- //
- // will set the crash key annotation named "MyCategory-key_name" to "value"
- // while in scope.
- #define SCOPED_CRASH_KEY_STRING32(category, name, data) \
- SCOPED_CRASH_KEY_STRING_INTERNAL(category, name, __COUNTER__, (data), \
- ::base::debug::CrashKeySize::Size32)
- #define SCOPED_CRASH_KEY_STRING64(category, name, data) \
- SCOPED_CRASH_KEY_STRING_INTERNAL(category, name, __COUNTER__, (data), \
- ::base::debug::CrashKeySize::Size64)
- #define SCOPED_CRASH_KEY_STRING256(category, name, data) \
- SCOPED_CRASH_KEY_STRING_INTERNAL(category, name, __COUNTER__, (data), \
- ::base::debug::CrashKeySize::Size256)
- #define SCOPED_CRASH_KEY_STRING1024(category, name, data) \
- SCOPED_CRASH_KEY_STRING_INTERNAL(category, name, __COUNTER__, (data), \
- ::base::debug::CrashKeySize::Size1024)
- #define SCOPED_CRASH_KEY_BOOL(category, name, data) \
- static_assert(std::is_same<std::decay_t<decltype(data)>, bool>::value, \
- "SCOPED_CRASH_KEY_BOOL must be passed a boolean value."); \
- SCOPED_CRASH_KEY_STRING32(category, name, (data) ? "true" : "false")
- #define SCOPED_CRASH_KEY_NUMBER(category, name, data) \
- SCOPED_CRASH_KEY_STRING32(category, name, ::base::NumberToString(data))
- ////////////////////////////////////////////////////////////////////////////////
- // The following declarations are used to initialize the crash key system
- // in //base by providing implementations for the above functions.
- // The virtual interface that provides the implementation for the crash key
- // API. This is implemented by a higher-layer component, and the instance is
- // set using the function below.
- class CrashKeyImplementation {
- public:
- virtual ~CrashKeyImplementation() = default;
- virtual CrashKeyString* Allocate(const char name[], CrashKeySize size) = 0;
- virtual void Set(CrashKeyString* crash_key, base::StringPiece value) = 0;
- virtual void Clear(CrashKeyString* crash_key) = 0;
- virtual void OutputCrashKeysToStream(std::ostream& out) = 0;
- };
- // Initializes the crash key system in base by replacing the existing
- // implementation, if it exists, with |impl|. The |impl| is copied into base.
- BASE_EXPORT void SetCrashKeyImplementation(
- std::unique_ptr<CrashKeyImplementation> impl);
- // The base structure for a crash key, storing the allocation metadata.
- struct CrashKeyString {
- constexpr CrashKeyString(const char name[], CrashKeySize size)
- : name(name), size(size) {}
- const char* const name;
- const CrashKeySize size;
- };
- } // namespace debug
- } // namespace base
- #endif // BASE_DEBUG_CRASH_LOGGING_H_
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