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53 lines
1.1 KiB
Go
53 lines
1.1 KiB
Go
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package version
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import (
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"fmt"
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"io"
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"internal/trace/v2/event"
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"internal/trace/v2/event/go122"
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)
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// Version represents the version of a trace file.
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type Version uint32
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const (
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Go122 Version = 22
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)
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var versions = map[Version][]event.Spec{
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Go122: go122.Specs(),
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}
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// Specs returns the set of event.Specs for this version.
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func (v Version) Specs() []event.Spec {
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return versions[v]
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}
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func (v Version) Valid() bool {
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_, ok := versions[v]
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return ok
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}
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// headerFmt is the format of the header of all Go execution traces.
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const headerFmt = "go 1.%d trace\x00\x00\x00"
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// ReadHeader reads the version of the trace out of the trace file's
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// header, whose prefix must be present in v.
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func ReadHeader(r io.Reader) (Version, error) {
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var v Version
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_, err := fmt.Fscanf(r, headerFmt, &v)
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if err != nil {
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return v, fmt.Errorf("bad file format: not a Go execution trace?")
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}
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if !v.Valid() {
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return v, fmt.Errorf("unknown or unsupported trace version go 1.%d", v)
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}
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return v, nil
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}
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// WriteHeader writes a header for a trace version v to w.
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func WriteHeader(w io.Writer, v Version) (int, error) {
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return fmt.Fprintf(w, headerFmt, v)
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}
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