57 lines
1.3 KiB
V
57 lines
1.3 KiB
V
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module context
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import time
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// A ValueContext carries a key-value pair. It implements Value for that key and
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// delegates all other calls to the embedded Context.
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pub struct ValueContext {
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key string
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value voidptr
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mut:
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context Context
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}
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// with_value returns a copy of parent in which the value associated with key is
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// val.
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//
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// Use context Values only for request-scoped data that transits processes and
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// APIs, not for passing optional parameters to functions.
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//
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// The provided key must be comparable and should not be of type
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// string or any other built-in type to avoid collisions between
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// packages using context. Users of with_value should define their own
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// types for keys
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pub fn with_value(parent Context, key string, value voidptr) &ValueContext {
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if isnil(key) {
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panic('nil key')
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}
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return &ValueContext{
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context: parent
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key: key
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value: value
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}
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}
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pub fn (ctx ValueContext) deadline() ?time.Time {
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return ctx.context.deadline()
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}
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pub fn (ctx ValueContext) done() chan int {
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return ctx.context.done()
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}
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pub fn (ctx ValueContext) err() string {
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return ctx.context.err()
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}
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pub fn (ctx ValueContext) value(key string) ?voidptr {
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if ctx.key == key {
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return ctx.value
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}
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return ctx.context.value(key)
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}
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pub fn (ctx ValueContext) str() string {
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return context_name(ctx.context) + '.with_value'
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}
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