| 1 | package shellrun |
| 2 | |
| 3 | import ( |
| 4 | "strings" |
| 5 | "unicode/utf8" |
| 6 | ) |
| 7 | |
| 8 | // completePrefix drops only a final partial rune. Interior invalid bytes retain |
| 9 | // their existing behavior; transport must not manufacture invalid boundary bytes. |
| 10 | func completePrefix(p []byte) []byte { |
| 11 | start := len(p) - 1 |
| 12 | for start >= 0 && !utf8.RuneStart(p[start]) { |
| 13 | start-- |
| 14 | } |
| 15 | if start >= 0 && !utf8.FullRune(p[start:]) { |
| 16 | return p[:start] |
| 17 | } |
| 18 | return p |
| 19 | } |
| 20 | |
| 21 | func completeTail(p []byte) []byte { |
| 22 | for len(p) > 0 && !utf8.RuneStart(p[0]) { |
| 23 | p = p[1:] |
| 24 | } |
| 25 | return completePrefix(p) |
| 26 | } |
| 27 | |
| 28 | // Flush finishes a progress stream after the owner has drained the child, |
| 29 | // including cancellation. An unfinished rune is represented once, not silently |
| 30 | // lost or emitted as several invalid JSON strings. |
| 31 | func (w *progressWriter) Flush() { |
| 32 | w.mu.Lock() |
| 33 | defer w.mu.Unlock() |
| 34 | if w.emit == nil || w.truncated { |
| 35 | return |
| 36 | } |
| 37 | w.writeUTF8(nil, true) |
| 38 | } |
| 39 | |
| 40 | func (w *progressWriter) writeUTF8(p []byte, final bool) { |
| 41 | // At most one additional rune is needed to detect truncation. Do not copy |
| 42 | // an arbitrarily large Write when joining it to a pending character. |
| 43 | p = p[:min(len(p), max(0, w.limit-w.forwarded)+utf8.UTFMax)] |
| 44 | if len(w.pending) > 0 { |
| 45 | p = append(w.pending, p...) |
| 46 | w.pending = nil |
| 47 | } |
| 48 | var out strings.Builder |
| 49 | truncated := false |
| 50 | for len(p) > 0 { |
| 51 | if !utf8.FullRune(p) { |
| 52 | if !final { |
| 53 | w.pending = append([]byte(nil), p...) |
| 54 | break |
| 55 | } |
| 56 | p = []byte(string(utf8.RuneError)) |
| 57 | } |
| 58 | r, size := utf8.DecodeRune(p) |
| 59 | encodedSize := size |
| 60 | if r == utf8.RuneError && size == 1 { |
| 61 | encodedSize = 3 |
| 62 | } |
| 63 | if w.forwarded+out.Len()+encodedSize > w.limit { |
| 64 | truncated = true |
| 65 | break |
| 66 | } |
| 67 | out.WriteRune(r) |
| 68 | p = p[size:] |
| 69 | } |
| 70 | if out.Len() > 0 { |
| 71 | w.forwarded += out.Len() |
| 72 | w.emit(out.String()) |
| 73 | } |
| 74 | if truncated { |
| 75 | w.truncated = true |
| 76 | w.pending = nil |
| 77 | if w.marker != "" { |
| 78 | w.emit(w.marker) |
| 79 | } |
| 80 | } |
| 81 | } |
| 82 |