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Zakk
6e6a7deed9
One `updating` flag guarded thirteen handlers, reads included: while a subscription update or a latency test ran, GET /touch answered REQUEST_IN_PROGRESS, so refreshing the page during a test failed at random. A touch is a database read and needs no turn. The flag becomes a turn that only the state-changing handlers take, and a handler that finds it taken waits up to five seconds before answering REQUEST_IN_PROGRESS instead of refusing at once; a client that leaves while waiting is not answered.
36 lines
986 B
Go
36 lines
986 B
Go
package controller
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import (
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"fmt"
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"time"
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"github.com/gin-gonic/gin"
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"github.com/v2rayA/v2rayA/common"
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)
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var (
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// mutation serialises the requests that rewrite the store or restart
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// the core. Reads do not take it: a touch during a latency test is a
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// database read and needs no turn.
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mutation = make(chan struct{}, 1)
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mutationWait = 5 * time.Second
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processingErr = common.Coded("REQUEST_IN_PROGRESS", fmt.Errorf("the last request is being processed"), nil)
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)
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// beginMutation waits for the turn to change state. When it returns false
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// the request has been answered with REQUEST_IN_PROGRESS, or the client
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// went away.
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func beginMutation(ctx *gin.Context) (release func(), ok bool) {
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timer := time.NewTimer(mutationWait)
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defer timer.Stop()
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select {
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case mutation <- struct{}{}:
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return func() { <-mutation }, true
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case <-timer.C:
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common.ResponseError(ctx, processingErr)
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return nil, false
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case <-ctx.Request.Context().Done():
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return nil, false
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}
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}
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