f3df6c8bc9
This prevents treating a flag that was explicitly set to the default as unchanged, since the explicit set is recorded in the new *cfgutil.ExplicitString flag type.
36 lines
1.4 KiB
Go
36 lines
1.4 KiB
Go
// Copyright (c) 2016 The btcsuite developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package cfgutil
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// ExplicitString is a string value implementing the flags.Marshaler and
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// flags.Unmarshaler interfaces so it may be used as a config struct field. It
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// records whether the value was explicitly set by the flags package. This is
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// useful when behavior must be modified depending on whether a flag was set by
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// the user or left as a default. Without recording this, it would be
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// impossible to determine whether flag with a default value was unmodified or
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// explicitly set to the default.
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type ExplicitString struct {
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Value string
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explicitlySet bool
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}
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// NewExplicitString creates a string flag with the provided default value.
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func NewExplicitString(defaultValue string) *ExplicitString {
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return &ExplicitString{Value: defaultValue, explicitlySet: false}
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}
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// ExplicitlySet returns whether the flag was explicitly set through the
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// flags.Unmarshaler interface.
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func (e *ExplicitString) ExplicitlySet() bool { return e.explicitlySet }
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// MarshalFlag implements the flags.Marshaler interface.
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func (e *ExplicitString) MarshalFlag() (string, error) { return e.Value, nil }
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// UnmarshalFlag implements the flags.Unmarshaler interface.
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func (e *ExplicitString) UnmarshalFlag(value string) error {
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e.Value = value
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e.explicitlySet = true
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return nil
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}
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