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Diffstat (limited to 'src/layout/parser.go')
| -rw-r--r-- | src/layout/parser.go | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/src/layout/parser.go b/src/layout/parser.go new file mode 100644 index 0000000..024fabb --- /dev/null +++ b/src/layout/parser.go @@ -0,0 +1,124 @@ +package layout + +import ( + "bufio" + "io" + "log" + "strconv" + "strings" +) + +// The syntax for the layout specification is: +// ``` +// (rowspan:)?widget(/weight)? +// ``` +// 1. Each line is a row +// 2. Empty lines are skipped +// 3. Spaces are compressed +// 4. Legal widget names are: cpu, disk, mem, temp, batt, net, procs +// 5. Names are not case sensitive +// 4. The simplest row is a single widget, by name, e.g. +// ``` +// cpu +// ``` +// 5. Widgets with no weights have a weight of 1. +// 6. If multiple widgets are put on a row with no weights, they will all have +// the same width. +// 7. Weights are integers +// 8. A widget will have a width proportional to its weight divided by the +// total weight count of the row. E.g., +// ``` +// cpu net +// disk/2 mem/4 +// ``` +// The first row will have two widgets: the CPU and network widgets; each +// will be 50% of the total width wide. The second row will have two +// widgets: disk and memory; the first will be 2/6 ~= 33% wide, and the +// second will be 5/7 ~= 67% wide (or, memory will be twice as wide as disk). +// 9. If prefixed by a number and colon, the widget will span that number of +// rows downward. E.g. +// ``` +// 2:cpu +// mem +// ``` +// The CPU widget will be twice as high as the memory widget. Similarly, +// ``` +// mem 2:cpu +// net +// ``` +// memory and network will be in the same row as CPU, one over the other, +// and each half as high as CPU. +// 10. Negative, 0, or non-integer weights will be recorded as "1". Same for row spans. +// 11. Unrecognized widgets will cause the application to abort. +// 12. In rows with multi-row spanning widgets **and** weights, weights in +// lower rows are ignored. Put the weight on the widgets in that row, not +// in later (spanned) rows. +// 13. Widgets are filled in top down, left-to-right order. +// 14. The larges row span in a row defines the top-level row span; all smaller +// row spans constitude sub-rows in the row. For example, `cpu mem/3 net/5` +// means that net/5 will be 5 rows tall overall, and mem will compose 3 of +// them. If following rows do not have enough widgets to fill the gaps, +// spacers will be used. +func ParseLayout(i io.Reader) layout { + r := bufio.NewScanner(i) + rv := layout{Rows: make([][]widgetRule, 0)} + var lineNo int + for r.Scan() { + l := strings.TrimSpace(r.Text()) + if l == "" { + continue + } + row := make([]widgetRule, 0) + ws := strings.Fields(l) + weightTotal := 0 + for _, w := range ws { + wr := widgetRule{Weight: 1} + ks := strings.Split(w, "/") + rs := strings.Split(ks[0], ":") + var wid string + if len(rs) > 1 { + v, e := strconv.Atoi(rs[0]) + if e != nil { + log.Printf("Layout error on line %d: format must be INT:STRING/INT. Error parsing %s as a int. Word was %s. Using a row height of 1.", lineNo, rs[0], w) + v = 1 + } + if v < 1 { + v = 1 + } + wr.Height = v + wid = rs[1] + } else { + wr.Height = 1 + wid = rs[0] + } + wr.Widget = strings.ToLower(wid) + if len(ks) > 1 { + weight, e := strconv.Atoi(ks[1]) + if e != nil { + log.Printf("Layout error on line %d: format must be STRING/INT. Error parsing %s as a int. Word was %s. Using a weight of 1 for widget.", lineNo, ks[1], w) + weight = 1 + } + if weight < 1 { + weight = 1 + } + wr.Weight = float64(weight) + if len(ks) > 2 { + log.Printf("Layout warning on line %d: too many '/' in word %s; ignoring extra junk.", lineNo, w) + } + weightTotal += weight + } else { + weightTotal += 1 + } + row = append(row, wr) + } + // Prevent tricksy users from breaking their own computers + if weightTotal <= 1 { + weightTotal = 1 + } + for i, w := range row { + row[i].Weight = w.Weight / float64(weightTotal) + } + rv.Rows = append(rv.Rows, row) + } + return rv +} |