ball_loggermanagerconfiguration.h

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/// @file ball_loggermanagerconfiguration.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// ball_loggermanagerconfiguration.h                                  -*-C++-*-
#ifndef INCLUDED_BALL_LOGGERMANAGERCONFIGURATION
#define INCLUDED_BALL_LOGGERMANAGERCONFIGURATION
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup ball_loggermanagerconfiguration ball_loggermanagerconfiguration
/// @brief  Provide a constrained-attribute class for the logger manager.
/// @addtogroup bal
/// @{
/// @addtogroup ball
/// @{
/// @addtogroup ball_loggermanagerconfiguration
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#ball_loggermanagerconfiguration-purpose"> Purpose</a>
/// * <a href="#ball_loggermanagerconfiguration-classes"> Classes </a>
/// * <a href="#ball_loggermanagerconfiguration-description"> Description </a>
///   * <a href="#ball_loggermanagerconfiguration-thread-safety"> Thread Safety </a>
///   * <a href="#ball_loggermanagerconfiguration-usage"> Usage </a>
///     * <a href="#ball_loggermanagerconfiguration-example-1-basic-usage"> Example 1: Basic Usage </a>
///
/// # Purpose {#ball_loggermanagerconfiguration-purpose}
/// Provide a constrained-attribute class for the logger manager.
///
/// # Classes {#ball_loggermanagerconfiguration-classes}
///
/// -  ball::LoggerManagerConfiguration: configuration spec for a logger manager
///
/// @see  ball_loggermanagerdefaults
///
/// # Description {#ball_loggermanagerconfiguration-description}
/// This component provides a constrained-attribute class that
/// contains a set of attributes (objects and parameters) of particular use to
/// logger managers.  The constraints are actively maintained by the class.  In
/// particular, the "set" methods for constrained values will fail if their
/// arguments are not consistent with the constraints.  Also, the constructor
/// does not take any constrained arguments, but rather sets those values to
/// valid defaults unconditionally.  This behavior avoids "silent failures",
/// since the constructor cannot explicitly return a status value.
///
/// The attributes of a `ball::LoggerManagerConfiguration` object and their
/// constraints are given, respectively, in two tables below.  Before listing
/// the attributes, however, we list the types that are provided by the
/// `ball::LoggerManagerConfiguration` class to simply the definition of some of
/// the attributes:
/// @code
/// TYPE                                         'typedef' alias
/// ------------------------------------------   ------------------------------
/// bsl::function<void(ball::UserFields *)>      UserFieldsPopulatorCallback
///
/// bsl::function<void(bsl::string *, const char *)>
///                                              CategoryNameFilterCallback
///
/// bsl::function<void(int *, int *, int *, int *, const char *)>
///                                              DefaultThresholdLevelsCallback
/// @endcode
/// The attributes contained by a `ball::LoggerManagerConfiguration` object
/// follow:
/// @code
/// TYPE                                         NAME
/// ------------------------------------------   ------------------------------
/// ball::LoggerManagerDefaults                  defaults
///
/// UserFieldsPopulatorCallback                  userFieldsPopulatorCallback
///
/// CategoryNameFilterCallback                   categoryNameFilterCallback
///
/// DefaultThresholdLevelsCallback               defaultThresholdLevelsCallback
///
/// LogOrder                                     logOrder
///
/// TriggerMarkers                               triggerMarkers
///
/// NAME                            DESCRIPTION
/// -------------------             -------------------------------------------
/// defaults                        constrained defaults for buffer size and
///                                 thresholds
///
/// userFieldsPopulatorCallback     populates user-defined fields in a log
///                                 record
///
/// categoryNameFilterCallback      invoked on category names, e.g., to re-map
///                                 characters
///
/// defaultThresholdLevelsCallback  sets category severity threshold levels (by
///                                 default)
///
/// logOrder                        defines the order in which log messages are
///                                 published for Trigger and Trigger-All
///                                 events; default is LIFO (last-in first-out)
///
/// triggerMarkers                  defines whether text will be written to the
///                                 log to indicate whether a series of log
///                                 records were logged due to either a Trigger
///                                 or Trigger-All event; if this attribute is
///                                 'e_BEGIN_END_MARKERS', then
///                                 "BEGIN RECORD DUMP" and "END RECORD DUMP"
///                                 will be written before and after each
///                                 sequence of records logged due to a Trigger
///                                 or Trigger-All event; default is
///                                 'e_BEGIN_END_MARKERS'.
/// @endcode
/// The constraints are as follows:
/// @code
///   NAME                             CONSTRAINT
/// +--------------------------------+--------------------------------+
/// | defaults                       | (a constrained-attribute type) |
/// +--------------------------------+--------------------------------+
/// | userFieldsPopulatorCallback    | (none)                         |
/// +--------------------------------+--------------------------------+
/// | categoryNameFilterCallback     | (none)                         |
/// +--------------------------------+--------------------------------+
/// | defaultThresholdLevelsCallback | (none)                         |
/// +--------------------------------+--------------------------------+
/// | logOrder                       | (none)                         |
/// +--------------------------------+--------------------------------+
/// | triggerMarkers                 | (none)                         |
/// +--------------------------------+--------------------------------+
/// @endcode
/// For convenience, the `ball::LoggerManagerConfiguration` interface contains
/// manipulators and accessors to configure and inspect the value of its
/// contained `ball::LoggerManagerDefaults` object; these methods are identical
/// to those of `ball::LoggerManagerDefaults`.  See the
/// @ref ball_loggermanagerdefaults  component for details on the defaults and
/// their constraints.
///
/// ## Thread Safety {#ball_loggermanagerconfiguration-thread-safety}
///
///
/// This constrained-attribute component is *thread-safe* but not
/// *thread-enabled*, and requires explicit synchronization in the user space.
/// Note that any of the contained user-defined callbacks may be invoked from
/// *any* thread, and the user must account for that.
///
/// ## Usage {#ball_loggermanagerconfiguration-usage}
///
///
/// This section illustrates intended use of this component.
///
/// ### Example 1: Basic Usage {#ball_loggermanagerconfiguration-example-1-basic-usage}
///
///
/// First, we define a simple function that will serve as a
/// `UserFieldsPopulatorCallback`, a callback that will be invoked for each
/// logged message to populate user defined fields for the log record:
/// @code
/// void exampleCallback(ball::UserFields *fields)
/// {
///     fields->appendString("example user field value");
/// }
/// @endcode
/// Next, we define a function `inititialize` in which we will create and
/// configure a `ball::LoggerManagerConfiguration` object (see
/// @ref ball_loggermanager  for an example of how to create the logger-manager
/// singleton object):
/// @code
/// void initializeConfiguration(bool verbose)
/// {
///   ball::LoggerManagerConfiguration config;
///
/// @endcode
/// Then, we configure the default record buffer size, logger buffer size, and
/// the various logging thresholds (see @ref ball_loggermanager  for more
/// information on the various threshold levels):
/// @code
///   if (0 != config.setDefaultRecordBufferSizeIfValid(32768) ||
///       0 != config.setDefaultLoggerBufferSizeIfValid(1024)  ||
///       0 != config.setDefaultThresholdLevelsIfValid(0, 64, 0, 0)) {
///      bsl::cerr << "Failed set log configuration defaults." << bsl::endl;
///      bsl::exit(-1);
///   }
///
///   assert(32768 == config.defaultRecordBufferSize());
///   assert( 1024 == config.defaultLoggerBufferSize());
///   assert(    0 == config.defaultRecordLevel());
///   assert(   64 == config.defaultPassLevel());
///   assert(    0 == config.defaultTriggerLevel());
///   assert(    0 == config.defaultTriggerAllLevel());
/// @endcode
/// Next, we populate the remaining attributes of our configuration object (note
/// that the following methods cannot fail and return `void`):
/// @code
///   config.setUserFieldsPopulatorCallback(&exampleCallback);
///   config.setLogOrder(ball::LoggerManagerConfiguration::e_FIFO);
///   config.setTriggerMarkers(ball::LoggerManagerConfiguration::e_NO_MARKERS);
/// @endcode
/// Now, we verify the options are configured correctly:
/// @code
///   assert(ball::LoggerManagerConfiguration::e_FIFO == config.logOrder());
///   assert(ball::LoggerManagerConfiguration::e_NO_MARKERS
///                                                == config.triggerMarkers());
/// @endcode
/// Finally, we print the configuration value to `stdout` and return:
/// @code
///   if (verbose) {
///     bsl::cout << config << bsl::endl;
///   }
/// }
/// @endcode
/// This produces the following (multi-line) output:
/// @code
/// [
///     Defaults:
///     [
///         recordBufferSize : 32768
///         loggerBufferSize : 1024
///         recordLevel      : 0
///         passLevel        : 64
///         triggerLevel     : 0
///         triggerAllLevel  : 0
///     ]
///     User Fields Populator functor is not null
///     Category Name Filter functor is null
///     Default Threshold Callback functor is null
///     Logging order is FIFO
///     Trigger markers are NO_MARKERS
/// ]
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bal
 * @{
 */
/** @addtogroup ball
 * @{
 */
/** @addtogroup ball_loggermanagerconfiguration
 * @{
 */
 
#include <balscm_version.h>
 
#include <ball_loggermanagerdefaults.h>
 
#include <bslma_allocator.h>
#include <bslma_usesbslmaallocator.h>
 
#include <bslmf_nestedtraitdeclaration.h>
 
#include <bsl_functional.h>
#include <bsl_iosfwd.h>
#include <bsl_string.h>
 
 
namespace ball {
 
class UserFields;
 
                    // ================================
                    // class LoggerManagerConfiguration
                    // ================================
 
/// This class provides constrained configuration parameters for a logger
/// manager.  The constraints are maintained as class invariants; it is not
/// possible to obtain an invalid object through this interface.
///
/// This class support *in-core* *value-semantic* operations, including
/// copy construction, assignment, and equality comparison; `ostream`
/// printing is supported, but in a modified form to handle functors, and
/// BDEX serialization cannot be supported at all.  (A precise operational
/// definition of when two instances have the same (in-core) value can be
/// found in the description of `operator==` for the class.)  This class is
/// *exception* *neutral* with no guarantee of rollback: If an exception is
/// thrown during the invocation of a method on a pre-existing instance, the
/// object is left in a valid state, but its value is undefined.  In no
/// event is memory leaked.  Finally, *aliasing* (e.g., using all or part of
/// an object as both source and destination) is supported in all cases.
///
/// See @ref ball_loggermanagerconfiguration 
class LoggerManagerConfiguration {
 
  public:
    // PUBLIC TYPES
 
    /// `UserFieldsPopulatorCallback` is the type of a user-supplied
    /// callback functor used to populate the user-defined fields in each
    /// log record.
    typedef bsl::function<void(ball::UserFields *)>
                                                   UserFieldsPopulatorCallback;
 
    /// `CategoryNameFilterCallback` is the type of the user-supplied
    /// functor that translates external category names to internal names.
    typedef bsl::function<void(bsl::string *, const char *)>
                                                    CategoryNameFilterCallback;
 
    /// `DefaultThresholdLevelsCallback` is the type of the functor that
    /// determines default threshold levels for categories added to the
    /// registry by the `setCategory(const char *)` method.
    typedef bsl::function<void(int *, int *, int *, int *, const char *)>
                                                DefaultThresholdLevelsCallback;
 
    enum LogOrder {
        // The 'LogOrder' enumeration defines the order in which messages will
        // be published to the underlying observer in the case of Trigger and
        // Trigger-All events.
 
        e_FIFO,  // oldest logged messages are published first
        e_LIFO   // newest logged messages are published first
 
#ifndef BDE_OMIT_INTERNAL_DEPRECATED
      , BAEL_FIFO = e_FIFO
      , BAEL_LIFO = e_LIFO
      , FIFO = e_FIFO
      , LIFO = e_LIFO
#endif // BDE_OMIT_INTERNAL_DEPRECATED
    };
 
    /// The `TriggerMarkers` enumeration defines whether text will be
    /// written to the log to indicate whether a series of log records were
    /// logged due to either a Trigger or Trigger-All event.  If this
    /// attribute is `e_BEGIN_END_MARKERS`, then "BEGIN RECORD DUMP" and
    /// "END RECORD DUMP" will be written before and after each sequence of
    /// records logged due to a Trigger or Trigger-All event.  The default
    /// value of this attribute is `e_BEGIN_END_MARKERS`.
    enum TriggerMarkers {
        e_NO_MARKERS,        // don't print any markers
 
        e_BEGIN_END_MARKERS  // print "BEGIN RECORD DUMP" and
                             // "END RECORD DUMP" markers (default)
 
#ifndef BDE_OMIT_INTERNAL_DEPRECATED
      , BAEL_NO_MARKERS        = e_NO_MARKERS
      , BAEL_BEGIN_END_MARKERS = e_BEGIN_END_MARKERS
 
      , NO_MARKERS             = e_NO_MARKERS
      , BEGIN_END_MARKERS      = e_BEGIN_END_MARKERS
#endif // BDE_OMIT_INTERNAL_DEPRECATED
    };
 
  private:
    // DATA
    LoggerManagerDefaults d_defaults;             // default buffer size for
                                                  // logger (for macros) and
                                                  // set of constrained default
                                                  // severity threshold levels
                                                  // for logger manager
 
    UserFieldsPopulatorCallback
                          d_userPopulator;        // user callback to add
                                                  // optional user-defined
                                                  // fields to a log record
 
    CategoryNameFilterCallback
                          d_categoryNameFilter;   // callback to modify input
                                                  // category names for
                                                  // internal storage
 
    DefaultThresholdLevelsCallback
                          d_defaultThresholdsCb;  // callback to supply default
                                                  // severity thresholds for
                                                  // categories
 
    LogOrder              d_logOrder;             // logging order
 
    TriggerMarkers        d_triggerMarkers;       // trigger marker
 
    bslma::Allocator     *d_allocator_p;          // memory allocator (held,
                                                  // not owned)
 
    // FRIENDS
    friend bsl::ostream& operator<<(bsl::ostream&,
                                    const LoggerManagerConfiguration&);
 
    friend bool operator==(const LoggerManagerConfiguration&,
                           const LoggerManagerConfiguration&);
 
  public:
    // CLASS METHODS
 
    /// Return `true` if the specified `numBytes` is a valid default-logger
    /// record-buffer size value, and `false` otherwise.  `numBytes` is
    /// valid if `0 < numBytes`.
    static bool isValidDefaultRecordBufferSize(int numBytes);
 
    /// Return `true` if the specified `numBytes` is a valid default
    /// logger-message-buffer size value, and `false` otherwise.  `numBytes`
    /// is valid if `0 < numBytes`.
    static bool isValidDefaultLoggerBufferSize(int numBytes);
 
    /// Return `true` if each of the specified `recordLevel`, `passLevel`,
    /// `triggerLevel`, and `triggerAllLevel` values is a valid default
    /// severity threshold level, and `false` otherwise.  Valid severity
    /// threshold levels are in the range `[0 .. 255]`.
    static bool areValidDefaultThresholdLevels(int recordLevel,
                                               int passLevel,
                                               int triggerLevel,
                                               int triggerAllLevel);
 
    // TRAITS
    BSLMF_NESTED_TRAIT_DECLARATION(LoggerManagerConfiguration,
                                   bslma::UsesBslmaAllocator);
 
    // CREATORS
 
    /// Create a logger manager configuration constrained-attribute object
    /// having valid default values for all attributes.  Optionally specify
    /// a `basicAllocator` used to supply memory.  If `basicAllocator` is 0,
    /// the currently installed default allocator is used.
    explicit LoggerManagerConfiguration(bslma::Allocator *basicAllocator = 0);
 
    /// Create a logger manager configuration constrained-attribute object
    /// having the in-core value of the specified `original` object.
    /// Optionally specify a `basicAllocator` used to supply memory.  If
    /// `basicAllocator` is 0, the currently installed default allocator is
    /// used.
    LoggerManagerConfiguration(
                        const LoggerManagerConfiguration&  original,
                        bslma::Allocator                  *basicAllocator = 0);
 
    /// Destroy this object.
     ~LoggerManagerConfiguration() = default;
 
    // MANIPULATORS
 
    /// Assign to this logger manager configuration constrained-attribute
    /// object the in-core value of the specified `rhs` object.
    LoggerManagerConfiguration& operator=(
                                        const LoggerManagerConfiguration& rhs);
 
    /// Set the default values attribute of this object to the specified
    /// `defaults`.  Note that, since `defaults` is itself a
    /// constrained-attribute object, this method cannot fail.
    void setDefaultValues(const LoggerManagerDefaults& defaults);
 
    /// Set the default-logger record-buffer size attribute of the
    /// `LoggerManagerDefaults` attribute of this object to the specified
    /// `numBytes` if `0 < numBytes`.  Return 0 on success, and a non-zero
    /// value otherwise with no effect on this object.
    int setDefaultRecordBufferSizeIfValid(int numBytes);
 
    /// Set the default logger-message-buffer size attribute of the
    /// `LoggerManagerDefaults` attribute of this object to the specified
    /// `numBytes` if `0 < numBytes`.  Return 0 on success, and a non-zero
    /// value otherwise with no effect on this object.
    int setDefaultLoggerBufferSizeIfValid(int numBytes);
 
    /// Set the passthrough severity threshold level attribute of the
    /// `LoggerManagerDefaults` attribute of this object to the specified
    /// `passLevel`, if it is in the range `[0 .. 255]`, and set all the
    /// other threshold levels (recordLevel, triggerLevel, triggerAllLevel)
    /// to 0.  Return 0 on success, and a non-zero value otherwise with no
    /// effect on this object.
    int setDefaultThresholdLevelsIfValid(int passLevel);
 
    /// Set the quadruplet of default severity threshold level attributes of
    /// the `LoggerManagerDefaults` attribute of this object to the
    /// specified `recordLevel`, `passLevel`, `triggerLevel`, and
    /// `triggerAllLevel` values if each level is in the range `[0 .. 255]`.
    /// Return 0 on success, and a non-zero value otherwise with no effect
    /// on this object.
    int setDefaultThresholdLevelsIfValid(int recordLevel,
                                         int passLevel,
                                         int triggerLevel,
                                         int triggerAllLevel);
 
    /// Set the user-fields populator callback attribute of this object to
    /// the specified `populatorCallback`.
    void setUserFieldsPopulatorCallback(
                         const UserFieldsPopulatorCallback& populatorCallback);
 
    /// Set the category name-filter callback functor attribute of this
    /// object to the specified `nameFilter`.  Note that this method cannot
    /// fail, and that `nameFilter` can be a "null" (i.e., unpopulated)
    /// functor object.
    void setCategoryNameFilterCallback(
                                 const CategoryNameFilterCallback& nameFilter);
 
    /// Set the default thresholds callback functor attribute of this object
    /// to the specified `thresholdsCb`.  Note that this method cannot fail,
    /// and that `thresholdsCb` can be a "null" (i.e., unpopulated) functor
    /// object.
    void setDefaultThresholdLevelsCallback(
                           const DefaultThresholdLevelsCallback& thresholdsCb);
 
    /// Set the log order attribute of this object to the specified `value`.
    void setLogOrder(LogOrder value);
 
    /// Set the trigger marker attribute of this object to the specified
    /// `value`.
    void setTriggerMarkers(TriggerMarkers value);
 
    // ACCESSORS
 
    /// Return a reference to the non-modifiable defaults object attribute
    /// of this object.
    const LoggerManagerDefaults& defaults() const;
 
    /// Return the default-logger record-buffer size attribute of the
    /// `LoggerManagerDefaults` attribute of this object.
    int defaultRecordBufferSize() const;
 
    /// Return the default logger-message-buffer size attribute of the
    /// `LoggerManagerDefaults` attribute of this object.
    int defaultLoggerBufferSize() const;
 
    /// Return the default Record threshold level attribute of the
    /// `LoggerManagerDefaults` attribute of this object.
    int defaultRecordLevel() const;
 
    /// Return the default Pass threshold level attribute of the
    /// `LoggerManagerDefaults` attribute of this object.
    int defaultPassLevel() const;
 
    /// Return the default Trigger threshold level attribute of the
    /// `LoggerManagerDefaults` attribute of this object.
    int defaultTriggerLevel() const;
 
    /// Return the default Trigger-All threshold level attribute of the
    /// `LoggerManagerDefaults` attribute of this object.
    int defaultTriggerAllLevel() const;
 
    /// Return a reference providing non-modifiable access to the
    /// user-fields populator functor attribute of this object.
    const UserFieldsPopulatorCallback& userFieldsPopulatorCallback() const;
 
    /// Return a reference to the non-modifiable category name filter
    /// functor attribute of this object.
    const CategoryNameFilterCallback& categoryNameFilterCallback() const;
 
    /// Return a reference to the non-modifiable default severity-level
    /// thresholds functor attribute of this object.
    const DefaultThresholdLevelsCallback&
                                        defaultThresholdLevelsCallback() const;
 
    /// Return the log order attribute of this object.  See attributes
    /// description for effects of the log order.
    LogOrder logOrder() const;
 
    /// Return the trigger marker attribute of this object.  See attributes
    /// description for effects of the trigger markers.
    TriggerMarkers triggerMarkers() const;
 
    /// Format a reasonable representation of this object to the specified
    /// output `stream` at the (absolute value of) the optionally specified
    /// indentation `level` and return a reference to `stream`.  If `level`
    /// is specified, optionally specify `spacesPerLevel`, the number of
    /// spaces per indentation level for this and all of its nested objects.
    /// If `level` is negative, suppress indentation of the first line.  If
    /// `spacesPerLevel` is negative, suppress all indentation AND format
    /// the entire output on one line.  If `stream` is not valid on entry,
    /// this operation has no effect.  The format will indicate whether the
    /// contained functors are or are not "null", but will not otherwise
    /// attempt to represent functor "values".
    bsl::ostream& print(bsl::ostream& stream,
                        int           level          = 0,
                        int           spacesPerLevel = 4) const;
};
 
// FREE OPERATORS
 
/// Return `true` if the specified `lhs` and `rhs` attribute objects have
/// the same (in-core) value, and `false` otherwise.  Two attribute objects
/// objects have the same in-core value if each respective attribute has the
/// same in-core value.  Note that functor attributes must have identically
/// the same representation to have the same in-core value.
bool operator==(const LoggerManagerConfiguration& lhs,
                const LoggerManagerConfiguration& rhs);
 
/// Return `true` if the specified `lhs` and `rhs` attribute objects do not
/// have the same (in-core) value, and `false` otherwise.  Two attribute
/// objects do not have the same in-core value if one or more respective
/// attributes differ in in-core values.  Note that functor attributes will
/// have different in-core values if their representations are not
/// identical.
bool operator!=(const LoggerManagerConfiguration& lhs,
                const LoggerManagerConfiguration& rhs);
 
/// Write a reasonable representation of the specified `configuration`
/// object to the specified output `stream`, indicating whether the
/// contained functors are or are not "null".
bsl::ostream& operator<<(bsl::ostream&                     stream,
                         const LoggerManagerConfiguration& configuration);
 
}  // close package namespace
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2015 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */