go.mway.dev/chrono@v0.6.1-0.20240126030049-189c5aef20d2/clock/options.go (about)

     1  // Copyright (c) 2023 Matt Way
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to
     5  // deal in the Software without restriction, including without limitation the
     6  // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
     7  // sell copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    18  // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
    19  // IN THE THE SOFTWARE.
    20  
    21  package clock
    22  
    23  import (
    24  	"time"
    25  
    26  	"go.mway.dev/chrono"
    27  )
    28  
    29  // A TimeFunc is a function that returns time as a [time.Time] object.
    30  type TimeFunc = func() time.Time
    31  
    32  // DefaultTimeFunc returns a new [TimeFunc] that uses [time.Now] to tell time.
    33  func DefaultTimeFunc() TimeFunc {
    34  	return time.Now
    35  }
    36  
    37  // A NanotimeFunc is a function that returns time as integer nanoseconds.
    38  type NanotimeFunc = func() int64
    39  
    40  // DefaultNanotimeFunc returns a new [NanotimeFunc] that uses [chrono.Nanotime]
    41  // to tell time.
    42  func DefaultNanotimeFunc() NanotimeFunc {
    43  	return chrono.Nanotime
    44  }
    45  
    46  // Options configure a [Clock].
    47  type Options struct {
    48  	// TimeFunc configures the [TimeFunc] for a [Clock].
    49  	// If both TimeFunc and NanotimeFunc are provided, NanotimeFunc is used.
    50  	TimeFunc TimeFunc
    51  	// NanotimeFunc configures the [NanotimeFunc] for a [Clock].
    52  	// If both TimeFunc and NanotimeFunc are provided, NanotimeFunc is used.
    53  	NanotimeFunc NanotimeFunc
    54  }
    55  
    56  // DefaultOptions returns a new [Options] with sane defaults.
    57  func DefaultOptions() Options {
    58  	return Options{
    59  		TimeFunc: DefaultTimeFunc(),
    60  	}
    61  }
    62  
    63  func (o Options) apply(opts *Options) {
    64  	if o.TimeFunc != nil {
    65  		opts.TimeFunc = o.TimeFunc
    66  	}
    67  
    68  	if o.NanotimeFunc != nil {
    69  		opts.NanotimeFunc = o.NanotimeFunc
    70  	}
    71  }
    72  
    73  // An Option configures a Clock.
    74  type Option interface {
    75  	apply(*Options)
    76  }
    77  
    78  type optionFunc func(*Options)
    79  
    80  func (f optionFunc) apply(o *Options) {
    81  	f(o)
    82  }
    83  
    84  // WithNanotimeFunc returns an [Option] that configures a [Clock] to use f as
    85  // its time function.
    86  func WithNanotimeFunc(f NanotimeFunc) Option {
    87  	return optionFunc(func(o *Options) {
    88  		o.NanotimeFunc = f
    89  		o.TimeFunc = nil
    90  	})
    91  }
    92  
    93  // WithTimeFunc returns an [Option] that configures a [Clock] to use f as its
    94  // time function.
    95  func WithTimeFunc(f TimeFunc) Option {
    96  	return optionFunc(func(o *Options) {
    97  		o.TimeFunc = f
    98  		o.NanotimeFunc = nil
    99  	})
   100  }