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Fix the scoping of "diff" so its value doesn't leak between loop iterations

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In the existing code, "diff" has function scope and the value from the
previous iteration may be used if it is not reset. This appears to be an
oversight. This commit changes its scope to the for loop body.

One confusing point is that the cursor movement escape sequences appear
to be necessary even if the requested movement is 0. I haven't been able
to figure out why this makes a difference.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This commit is contained in:
Aaron Lehmann 2015-12-07 17:01:47 -08:00
parent 5821bbd01d
commit 6e9a3453f7
1 changed files with 7 additions and 4 deletions
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7
jsonmessage/jsonmessage.go
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@ -152,9 +152,9 @@ func DisplayJSONMessagesStream(in io.Reader, out io.Writer, terminalFd uintptr,
var (
dec = json.NewDecoder(in)
ids = make(map[string]int)
diff = 0
)
for {
diff := 0
var jm JSONMessage
if err := dec.Decode(&jm); err != nil {
if err == io.EOF {
@ -180,11 +180,12 @@ func DisplayJSONMessagesStream(in io.Reader, out io.Writer, terminalFd uintptr,
if isTerminal {
fmt.Fprintf(out, "\n")
}
diff = 0
} else {
diff = len(ids) - line
}
if jm.ID != "" && isTerminal {
// NOTE: this appears to be necessary even if
// diff == 0.
// <ESC>[{diff}A = move cursor up diff rows
fmt.Fprintf(out, "%c[%dA", 27, diff)
}
@ -198,6 +199,8 @@ func DisplayJSONMessagesStream(in io.Reader, out io.Writer, terminalFd uintptr,
}
err := jm.Display(out, isTerminal)
if jm.ID != "" && isTerminal {
// NOTE: this appears to be necessary even if
// diff == 0.
// <ESC>[{diff}B = move cursor down diff rows
fmt.Fprintf(out, "%c[%dB", 27, diff)
}