Add CLI helpers and BuildTree heuristic

The BuildTree implementation was in parallel-build-tools, which actually makes
sense to share in the compiler as can be used as another way to trigger
builds.

The CLI helpers were split in several CIs
implementations. This moves a new layout where we expose several
packages, as we will refactor things slowly.

pkg/compiler/buildtree.go

@@ -0,0 +1,140 @@
+// Copyright © 2021 Ettore Di Giacinto <mudler@mocaccino.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, see <http://www.gnu.org/licenses/>.
+
+package compiler
+
+import (
+	"encoding/json"
+	"sort"
+)
+
+func rankMapStringInt(values map[string]int) []string {
+	type kv struct {
+		Key   string
+		Value int
+	}
+	var ss []kv
+	for k, v := range values {
+		ss = append(ss, kv{k, v})
+	}
+	sort.Slice(ss, func(i, j int) bool {
+		return ss[i].Value > ss[j].Value
+	})
+	ranked := make([]string, len(values))
+	for i, kv := range ss {
+		ranked[i] = kv.Key
+	}
+	return ranked
+}
+
+type BuildTree struct {
+	order map[string]int
+}
+
+func (bt *BuildTree) Increase(s string) {
+	if bt.order == nil {
+		bt.order = make(map[string]int)
+	}
+	if _, ok := bt.order[s]; !ok {
+		bt.order[s] = 0
+	}
+
+	bt.order[s]++
+}
+
+func (bt *BuildTree) Reset(s string) {
+	if bt.order == nil {
+		bt.order = make(map[string]int)
+	}
+	bt.order[s] = 0
+}
+
+func (bt *BuildTree) Level(s string) int {
+	return bt.order[s]
+}
+
+func ints(input []int) []int {
+	u := make([]int, 0, len(input))
+	m := make(map[int]bool)
+
+	for _, val := range input {
+		if _, ok := m[val]; !ok {
+			m[val] = true
+			u = append(u, val)
+		}
+	}
+
+	return u
+}
+
+func (bt *BuildTree) AllInLevel(l int) []string {
+	var all []string
+	for k, v := range bt.order {
+		if v == l {
+			all = append(all, k)
+		}
+	}
+	return all
+}
+
+func (bt *BuildTree) Order(compilationTree map[string]map[string]interface{}) {
+	sentinel := false
+	for !sentinel {
+		sentinel = true
+
+	LEVEL:
+		for _, l := range bt.AllLevels() {
+
+			for _, j := range bt.AllInLevel(l) {
+				for _, k := range bt.AllInLevel(l) {
+					if j == k {
+						continue
+					}
+					if _, ok := compilationTree[j][k]; ok {
+						if bt.Level(j) == bt.Level(k) {
+							bt.Increase(j)
+							sentinel = false
+							break LEVEL
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+func (bt *BuildTree) AllLevels() []int {
+	var all []int
+	for _, v := range bt.order {
+		all = append(all, v)
+	}
+
+	sort.Sort(sort.IntSlice(all))
+
+	return ints(all)
+}
+
+func (bt *BuildTree) JSON() (string, error) {
+	type buildjob struct {
+		Jobs []string `json:"packages"`
+	}
+
+	result := []buildjob{}
+	for _, l := range bt.AllLevels() {
+		result = append(result, buildjob{Jobs: bt.AllInLevel(l)})
+	}
+	dat, err := json.Marshal(&result)
+	return string(dat), err
+}