/*
 * Copyright (c) 2015-2016 Apple Inc. All rights reserved.
 */

#ifndef __OS_LOG_H__
#define __OS_LOG_H__

#include <stdint.h>
#include <stdbool.h>
#include <mach-o/loader.h>
#include <os/availability.h>
#include <os/base.h>
#include <os/object.h>
#include <os/trace.h>

#if !__has_builtin(__builtin_os_log_format)
#error using os/log.h requires Xcode 8 or later
#endif

__BEGIN_DECLS

#if OS_OBJECT_SWIFT3
OS_OBJECT_DECL_SWIFT(os_log);
#elif OS_OBJECT_USE_OBJC
OS_OBJECT_DECL(os_log);
#elif defined(__has_ptrcheck)
typedef struct os_log_s *__single os_log_t;
#else
typedef struct os_log_s *os_log_t;
#endif /* OS_OBJECT_USE_OBJC */

/*!
 * @const OS_LOG_DISABLED
 *
 * @discussion
 * Use this to disable a specific log message.
 */
#if OS_LOG_TARGET_HAS_10_13_FEATURES
#define OS_LOG_DISABLED OS_OBJECT_GLOBAL_OBJECT(os_log_t, _os_log_disabled)
API_AVAILABLE(macosx(10.13), ios(11.0), watchos(4.0), tvos(11.0))
OS_EXPORT
struct os_log_s _os_log_disabled;
#else
#define OS_LOG_DISABLED ((os_log_t _Nonnull)NULL)
#endif

/*!
 * @const OS_LOG_DEFAULT
 *
 * @discussion
 * Use this to log a message in accordance with current system settings.
 */
#define OS_LOG_DEFAULT OS_OBJECT_GLOBAL_OBJECT(os_log_t, _os_log_default)
API_AVAILABLE(macos(10.11), ios(9.0), watchos(2.0), tvos(9.0))
OS_EXPORT
struct os_log_s _os_log_default;

/*!
 * @enum os_log_type_t
 *
 * @discussion
 * Supported log message types.
 *
 * @constant OS_LOG_TYPE_DEFAULT
 * Equivalent type for "os_log()" messages, i.e., default messages that are
 * always captured to memory or disk.
 *
 * @constant OS_LOG_TYPE_INFO
 * Equivalent type for "os_log_info()" messages, i.e., additional informational
 * messages.
 *
 * @constant OS_LOG_TYPE_DEBUG
 * Equivalent type for "os_log_debug()" messages, i.e., debug messages.
 *
 * @constant OS_LOG_TYPE_ERROR
 * Equivalent type for "os_log_error()" messages, i.e., messages indicating
 * error conditions.
 *
 * @constant OS_LOG_TYPE_FAULT
 * Equivalent type for "os_log_fault()" messages, i.e., messages indicating
 * that an unexpected condition occurred that likely indicates the presence of a
 * bug.
 */
OS_ENUM(os_log_type, uint8_t,
    OS_LOG_TYPE_DEFAULT = 0x00,
    OS_LOG_TYPE_INFO    = 0x01,
    OS_LOG_TYPE_DEBUG   = 0x02,
    OS_LOG_TYPE_ERROR   = 0x10,
    OS_LOG_TYPE_FAULT   = 0x11,
);

/*!
 * @function os_log_create
 *
 * @abstract
 * Creates a log object to be used with other log related functions.
 *
 * @discussion
 * Creates a log object to be used with other log related functions.  The
 * log object serves two purposes:  (1) tag related messages by subsystem
 * and category name for easy filtering, and (2) control logging system
 * behavior for messages.
 *
 * @param subsystem
 * The identifier of the given subsystem should be in reverse DNS form
 * (i.e., com.company.mysubsystem).
 *
 * @param category
 * The category within the given subsystem that specifies the settings for
 * the log object.
 *
 * @result
 * Returns an os_log_t value to be passed to other os_log API calls.  The
 * logging runtime maintains a global collection of all os_log_t objects, one
 * per subsystem/category pair.  The os_log_t for a given subsystem/category is
 * created upon the first call to os_log_create and any subsequent calls return
 * the same object.  These objects are never deallocated, so dynamic creation
 * (e.g. on a per-operation basis) is generally inappropriate.
 *
 * A value will always be returned to allow for dynamic enablement.
 */
API_AVAILABLE(macos(10.12), ios(10.0), watchos(3.0), tvos(10.0))
OS_EXPORT OS_NOTHROW OS_WARN_RESULT OS_OBJECT_RETURNS_RETAINED OS_NONNULL_ALL
os_log_t
os_log_create(const char *subsystem, const char *category);

/*!
 * @function os_log_info_enabled
 *
 * @abstract
 * Returns if additional information is enabled
 *
 * @discussion
 * Returns if additional information is enabled
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @result
 * Returns ‘true’ if info log messages are enabled.
 */
#define os_log_info_enabled(log) os_log_type_enabled(log, OS_LOG_TYPE_INFO)

/*!
 * @function os_log_debug_enabled
 *
 * @abstract
 * Returns if debug log messages are enabled for a particular log object.
 *
 * @discussion
 * Returns if debug log messages are enabled for a particular log object.
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @result
 * Returns ‘true’ if debug log messages are enabled.
 */
#define os_log_debug_enabled(log)  os_log_type_enabled(log, OS_LOG_TYPE_DEBUG)

/*!
 * @function os_log_with_type
 *
 * @abstract
 * Log a message using a specific type.
 *
 * @discussion
 * Will log a message with the provided os_log_type_t.
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @param type
 * Pass a valid type from os_log_type_t.
 *
 * @param format
 * A format string to generate a human-readable log message when the log
 * line is decoded.  This string must be a constant string, not dynamically
 * generated.  Supports all standard printf types in addition to %@ (objects).
 */
#define os_log_with_type(log, type, format, ...) __extension__({ \
    os_log_t _log_tmp = (log); \
    os_log_type_t _type_tmp = (type); \
    if (os_log_type_enabled(_log_tmp, _type_tmp)) { \
        OS_LOG_CALL_WITH_FORMAT(_os_log_impl, \
                (&__dso_handle, _log_tmp, _type_tmp), format, ##__VA_ARGS__); \
    } \
})

/*!
 * @function os_log
 *
 * @abstract
 * Insert a log message into the Unified Logging and Tracing system.
 *
 * @discussion
 * Insert a log message into the Unified Logging and Tracing system in
 * accordance with the preferences specified by the provided log object.
 * These messages cannot be disabled and therefore always captured either
 * to memory or disk.
 *
 * When an os_activity_id_t is present, the log message will also be scoped by
 * that identifier.  Activities provide granular filtering of log messages
 * across threads and processes.
 *
 * There is a physical cap of 1024 bytes per log line for dynamic content,
 * such as %s and %@, that can be written to the persistence store.
 * All content exceeding the limit will be truncated before it is
 * written to disk.
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @param format
 * A format string to generate a human-readable log message when the log
 * line is decoded.  This string must be a constant string, not dynamically
 * generated.  Supports all standard printf types and %@ (objects).
 */
#define os_log(log, format, ...) \
        os_log_with_type(log, OS_LOG_TYPE_DEFAULT, format, ##__VA_ARGS__)


/*!
 * @function os_log_info
 *
 * @abstract
 * Insert an additional information log message into the Unified Logging
 * and Tracing system.
 *
 * @discussion
 * Insert a log message into the Unified Logging and Tracing system in
 * accordance with the preferences specified by the provided log object.
 *
 * When an os_activity_id_t is present, the log message will also be scoped by
 * that identifier.  Activities provide granular filtering of log messages
 * across threads and processes.
 *
 * There is a physical cap of 256 bytes per entry for dynamic content,
 * i.e., %s and %@, that can be written to the persistence store.  As such,
 * all content exceeding the limit will be truncated before written to disk.
 * Live streams will continue to show the full content.
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @param format
 * A format string to generate a human-readable log message when the log
 * line is decoded.  This string must be a constant string, not dynamically
 * generated.  Supports all standard printf types and %@ (objects).
 */
#define os_log_info(log, format, ...) \
        os_log_with_type(log, OS_LOG_TYPE_INFO, format, ##__VA_ARGS__)

/*!
 * @function os_log_debug
 *
 * @abstract
 * Insert a debug log message into the Unified Logging and Tracing system.
 *
 * @discussion
 * Insert a debug log message into the Unified Logging and Tracing system in
 * accordance with the preferences specified by the provided log object.
 *
 * When an os_activity_id_t is present, the log message will also be scoped by
 * that identifier.  Activities provide granular filtering of log messages
 * across threads and processes.
 *
 * There is a physical cap of 256 bytes per entry for dynamic content,
 * i.e., %s and %@, that can be written to the persistence store.  As such,
 * all content exceeding the limit will be truncated before written to disk.
 * Live streams will continue to show the full content.
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @param format
 * A format string to generate a human-readable log message when the log
 * line is decoded.  This string must be a constant string, not dynamically
 * generated.  Supports all standard printf types and %@ (objects).
 */
#if OS_LOG_TARGET_HAS_10_15_FEATURES
#define os_log_debug(log, format, ...) __extension__({ \
    os_log_t _log_tmp = (log); \
    os_log_type_t _type_tmp = OS_LOG_TYPE_DEBUG; \
    if (os_log_type_enabled(_log_tmp, _type_tmp)) { \
        OS_LOG_CALL_WITH_FORMAT(_os_log_debug_impl, \
                (&__dso_handle, _log_tmp, _type_tmp), format, ##__VA_ARGS__); \
    } \
})
#else
#define os_log_debug(log, format, ...) \
        os_log_with_type(log, OS_LOG_TYPE_DEBUG, format, ##__VA_ARGS__)
#endif // OS_LOG_TARGET_HAS_10_15_FEATURES

/*!
 * @function os_log_error
 *
 * @abstract
 * Insert an error log message into the Unified Logging and Tracing system.
 *
 * @discussion
 * Insert an error log message into the Unified Logging and Tracing system.
 *
 * When an os_activity_id_t is present, the log message will also be scoped by
 * that identifier.  Activities provide granular filtering of log messages
 * across threads and processes.
 *
 * There is a physical cap of 256 bytes per entry for dynamic content,
 * i.e., %s and %@, that can be written to the persistence store.  As such,
 * all content exceeding the limit will be truncated before written to disk.
 * Live streams will continue to show the full content.
 *
 * Note, in a debugger, it is possible to set a breakpoint on _os_log_error_impl
 * to break on any error being emitted.
 *
 * A common use of os_log_error is to log failures from system calls and
 * library functions, including the value of errno.  Like other system calls
 * and library functions, the os_log functions do not preserve the value of
 * errno across calls.  errno can change even if the log message is logged
 * successfully.  Consider saving errno into a local variable before calling
 * os_log, if you still need errno's value afterward.
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @param format
 * A format string to generate a human-readable log message when the log
 * line is decoded.  This string must be a constant string, not dynamically
 * generated.  Supports all standard printf types and %@ (objects).
 */
#if OS_LOG_TARGET_HAS_10_13_FEATURES
#define os_log_error(log, format, ...) __extension__({ \
    os_log_t _log_tmp = (log); \
    os_log_type_t _type_tmp = OS_LOG_TYPE_ERROR; \
    if (os_log_type_enabled(_log_tmp, _type_tmp)) { \
        OS_LOG_CALL_WITH_FORMAT(_os_log_error_impl, \
                (&__dso_handle, _log_tmp, _type_tmp), format, ##__VA_ARGS__); \
    } \
})
#else
#define os_log_error(log, format, ...) \
        os_log_with_type(log, OS_LOG_TYPE_ERROR, format, ##__VA_ARGS__)
#endif // OS_LOG_TARGET_HAS_10_13_FEATURES

/*!
 * @function os_log_fault
 *
 * @abstract
 * Insert a fault log message into the Unified Logging and Tracing system.
 *
 * @discussion
 * Log a fault message into the Unified Logging and Tracing system.
 *
 * Faults should be used to report conditions which indicate the
 * presence of a bug.  Faults will gather more expensive contextual information
 * and record it for later inspection.  They may also be reported to other
 * debugging tools for display or aggregation.
 *
 * Note that faults should only be used for unexpected error conditions in
 * which there's a clear and safe recovery path. 
 *
 * When an os_activity_id_t is present, the log message will also be scoped by
 * that identifier.  Activities provide granular filtering of log messages
 * across threads and processes.
 *
 * There is a physical cap of 256 bytes per entry for dynamic content,
 * i.e., %s and %@, that can be written to the persistence store.  As such,
 * all content exceeding the limit will be truncated before written to disk.
 * Live streams will continue to show the full content.
 *
 * When composing user provided strings libtrace will cap the size in total of
 * format specifiers. See libtrace/libtrace/format_internal.h for details.
 * Libtrace will also truncate the total composed message to a length of
 * EXIT_REASON_PAYLOAD_MAX_LEN bytes, which is the kernel's maximum limit
 * for fault message length. See xnu/osfmk/kern/kcdata.h for details.
 * Libtrace will truncate all fault payloads regardless of oversize messages
 * being enabled before calling into the kernel.
 *
 * Note, in a debugger, it is possible to set a breakpoint on _os_log_fault_impl
 * to break on any fault being emitted.
 *
 * @param log
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @param format
 * A format string to generate a human-readable log message when the log
 * line is decoded.  This string must be a constant string, not dynamically
 * generated.  Supports all standard printf types and %@ (objects).
 */
#if OS_LOG_TARGET_HAS_10_13_FEATURES
#define os_log_fault(log, format, ...) __extension__({ \
    os_log_t _log_tmp = (log); \
    os_log_type_t _type_tmp = OS_LOG_TYPE_FAULT; \
    if (os_log_type_enabled(_log_tmp, _type_tmp)) { \
        OS_LOG_CALL_WITH_FORMAT(_os_log_fault_impl, \
                (&__dso_handle, _log_tmp, _type_tmp), format, ##__VA_ARGS__); \
    } \
})
#else
#define os_log_fault(log, format, ...) \
        os_log_with_type(log, OS_LOG_TYPE_FAULT, format, ##__VA_ARGS__)
#endif // OS_LOG_TARGET_HAS_10_13_FEATURES

/*!
 * @function os_log_type_enabled
 *
 * @abstract
 * Evaluate if a specific log type is enabled before doing work
 *
 * @discussion
 * Evaluate if a specific log type is enabled before doing work
 *
 * @param oslog
 * Pass OS_LOG_DEFAULT or a log object previously created with os_log_create.
 *
 * @param type
 * Pass a valid type from os_log_type_t.
 *
 * @result
 * Will return a boolean.
 */
API_AVAILABLE(macos(10.12), ios(10.0), watchos(3.0), tvos(10.0))
OS_EXPORT OS_NOTHROW OS_WARN_RESULT OS_PURE
bool
os_log_type_enabled(os_log_t oslog, os_log_type_t type);

/*!
 * @function _os_log_impl
 *
 * @abstract
 * Internal function that takes compiler generated encoding and captures the necessary content.
 */
API_AVAILABLE(macos(10.12), ios(10.0), watchos(3.0), tvos(10.0))
OS_EXPORT OS_NOTHROW OS_NOT_TAIL_CALLED
void
_os_log_impl(void *dso, os_log_t log, os_log_type_t type,
        const char *format, uint8_t *buf, uint32_t size);

/*!
 * @function _os_log_debug_impl
 *
 * @abstract
 * Internal function that is taken for any debug log emitted in the system.
 */
API_AVAILABLE(macos(10.15), ios(13.0), tvos(13.0), watchos(6.0))
OS_EXPORT OS_NOTHROW OS_NOT_TAIL_CALLED OS_COLD
void
_os_log_debug_impl(void *dso, os_log_t log, os_log_type_t type,
        const char *format, uint8_t *buf, uint32_t size);

/*!
 * @function _os_log_error_impl
 *
 * @abstract
 * Internal function that is taken for any error emitted in the system.
 */
API_AVAILABLE(macos(10.13), ios(11.0), tvos(11.0), watchos(4.0))
OS_EXPORT OS_NOTHROW OS_NOT_TAIL_CALLED OS_COLD
void
_os_log_error_impl(void *dso, os_log_t log, os_log_type_t type,
        const char *format, uint8_t *buf, uint32_t size);

/*!
 * @function _os_log_fault_impl
 *
 * @abstract
 * Internal function that is taken for any fault emitted in the system.
 */
API_AVAILABLE(macos(10.13), ios(11.0), tvos(11.0), watchos(4.0))
OS_EXPORT OS_NOTHROW OS_NOT_TAIL_CALLED OS_COLD
void
_os_log_fault_impl(void *dso, os_log_t log, os_log_type_t type,
        const char *format, uint8_t *buf, uint32_t size);

/*
 * Support for older iteration of API for source compatibility only...
 */

API_DEPRECATED("no longer supported, use os_log_debug(OS_LOG_DEFAULT, ...)",
        macos(10.11,10.12), ios(9.0,10.0), watchos(2.0,3.0), tvos(9.0,10.0))
OS_EXPORT OS_NOTHROW OS_NOT_TAIL_CALLED
void
_os_log_internal(void *dso, os_log_t log, os_log_type_t type, const char *message, ...);

API_AVAILABLE(macos(10.11), ios(9.0), watchos(2.0), tvos(9.0))
OS_EXPORT OS_NOTHROW OS_WARN_RESULT OS_OBJECT_RETURNS_RETAINED OS_NOT_TAIL_CALLED OS_NONNULL_ALL
os_log_t
_os_log_create(void *dso, const char *subsystem, const char *category);

API_DEPRECATED("no longer suppored - always returns true",
        macos(10.11,10.12), ios(9.0,10.0), watchos(2.0,3.0), tvos(9.0,10.0))
OS_EXPORT OS_NOTHROW OS_WARN_RESULT
bool
os_log_is_enabled(os_log_t log);

API_DEPRECATED_WITH_REPLACEMENT("os_log_debug_enabled",
        macos(10.11,10.12), ios(9.0,10.0), watchos(2.0,3.0), tvos(9.0,10.0))
OS_EXPORT OS_NOTHROW OS_WARN_RESULT
bool
os_log_is_debug_enabled(os_log_t log);

API_DEPRECATED("no longer supported - use os_log with per-parameter privacy options",
        macos(10.11,10.12), ios(9.0,10.0), watchos(2.0,3.0), tvos(9.0,10.0))
OS_NOTHROW OS_ALWAYS_INLINE
static inline void
_os_log_sensitive_deprecated(void) { }

#define os_log_sensitive(log, format, ...) __extension__({              \
    os_log_with_type(log, OS_LOG_TYPE_DEFAULT, format, ##__VA_ARGS__);  \
    _os_log_sensitive_deprecated();                                     \
})

#define os_log_sensitive_debug(log, format, ...) __extension__({        \
    os_log_with_type(log, OS_LOG_TYPE_DEBUG, format, ##__VA_ARGS__);    \
    _os_log_sensitive_deprecated();                                     \
})

#if !OS_LOG_TARGET_HAS_10_12_FEATURES
#undef os_log_with_type
#define os_log_with_type(log, type, format, ...) __extension__({ \
    _Pragma("clang diagnostic push") \
    _Pragma("clang diagnostic error \"-Wformat\"") \
    _Static_assert(__builtin_constant_p(format), "format argument must be a string constant"); \
    _os_log_internal(&__dso_handle, log, type, format, ##__VA_ARGS__); \
    _Pragma("clang diagnostic pop") \
})

#undef os_log_debug_enabled
#define os_log_debug_enabled(...) os_log_is_debug_enabled(__VA_ARGS__)

#undef os_log_create
#define os_log_create(subsystem, category) \
        _os_log_create(&__dso_handle, subsystem, category)
#endif // !OS_LOG_TARGET_HAS_10_12_FEATURES

__END_DECLS

#endif // !__OS_LOG_H__