Initial QSfera import

Server/vendor/github.com/olekukonko/tablewriter/pkg/twwidth/tab.go

@@ -0,0 +1,288 @@
+package twwidth
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+)
+
+type Tab rune
+
+const (
+	TabWidthDefault     = 8
+	TabString       Tab = '\t'
+)
+
+// IsTab returns true if t equals the default tab.
+func (t Tab) IsTab() bool {
+	return t == TabString
+}
+
+func (t Tab) Byte() byte {
+	return byte(t)
+}
+
+func (t Tab) Rune() rune {
+	return rune(t)
+}
+
+func (t Tab) String() string {
+	return string(t)
+}
+
+// IsTab returns true if r is a tab rune.
+func IsTab(r rune) bool {
+	return r == TabString.Rune()
+}
+
+type Tabinal struct {
+	once  sync.Once
+	width int
+	mu    sync.RWMutex
+}
+
+func (t *Tabinal) String() string {
+	return TabString.String()
+}
+
+// Size returns the current tab width, default if unset.
+func (t *Tabinal) Size() int {
+	t.once.Do(t.init)
+
+	t.mu.RLock()
+	w := t.width
+	t.mu.RUnlock()
+
+	if w <= 0 {
+		return TabWidthDefault
+	}
+	return w
+}
+
+// SetWidth sets the tab width if valid (1–32).
+func (t *Tabinal) SetWidth(w int) {
+	if w <= 0 || w > 32 {
+		return
+	}
+	t.mu.Lock()
+	t.width = w
+	t.mu.Unlock()
+}
+
+func (t *Tabinal) init() {
+	w := t.detect()
+	t.mu.Lock()
+	t.width = w
+	t.mu.Unlock()
+}
+
+// detect determines tab width using env, editorconfig, project, or term.
+func (t *Tabinal) detect() int {
+	if w := envInt("TABWIDTH"); w > 0 {
+		return clamp(w)
+	}
+	if w := envInt("TS"); w > 0 {
+		return clamp(w)
+	}
+	if w := envInt("VIM_TABSTOP"); w > 0 {
+		return clamp(w)
+	}
+	if w := editorConfigTabWidth(); w > 0 {
+		return w
+	}
+	if w := projectHeuristic(); w > 0 {
+		return w
+	}
+	if w := termHeuristic(); w > 0 {
+		return w
+	}
+	return 0
+}
+
+func editorConfigTabWidth() int {
+	dir, err := os.Getwd()
+	if err != nil {
+		return 0
+	}
+
+	for dir != "" && dir != "/" && dir != "." {
+		path := filepath.Join(dir, ".editorconfig")
+		if w := parseEditorConfig(path); w > 0 {
+			return clamp(w)
+		}
+		parent := filepath.Dir(dir)
+		if parent == dir {
+			break
+		}
+		dir = parent
+	}
+	return 0
+}
+
+// parseEditorConfig reads tab_width or indent_size from a file.
+func parseEditorConfig(path string) int {
+	f, err := os.Open(path)
+	if err != nil {
+		return 0
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	inMatch := false
+	globalWidth := 0
+
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") || strings.HasPrefix(line, ";") {
+			continue
+		}
+
+		if strings.HasPrefix(line, "[") && strings.HasSuffix(line, "]") {
+			pattern := line[1 : len(line)-1]
+			inMatch = pattern == "*"
+
+			knownExts := []string{".go", ".py", ".js", ".ts", ".java", ".rs"}
+			for _, ext := range knownExts {
+				if strings.Contains(pattern, ext) {
+					inMatch = true
+					break
+				}
+			}
+			continue
+		}
+
+		if !inMatch && globalWidth == 0 {
+			continue
+		}
+
+		parts := strings.SplitN(line, "=", 2)
+		if len(parts) != 2 {
+			continue
+		}
+		key := strings.TrimSpace(parts[0])
+		val := strings.TrimSpace(parts[1])
+
+		switch key {
+		case "tab_width":
+			if w, err := strconv.Atoi(val); err == nil && w > 0 {
+				if inMatch {
+					return clamp(w)
+				}
+				if globalWidth == 0 {
+					globalWidth = w
+				}
+			}
+		case "indent_size":
+			if val == "tab" {
+				continue
+			}
+			if w, err := strconv.Atoi(val); err == nil && w > 0 {
+				if inMatch {
+					return clamp(w)
+				}
+				if globalWidth == 0 {
+					globalWidth = w
+				}
+			}
+		}
+	}
+
+	return globalWidth
+}
+
+// projectHeuristic returns 4 for known project types.
+func projectHeuristic() int {
+	dir, err := os.Getwd()
+	if err != nil {
+		return 0
+	}
+
+	indicators := []string{
+		"go.mod", "go.sum",
+		"package.json", "package-lock.json", "yarn.lock", "pnpm-lock.yaml",
+		"setup.py", "pyproject.toml", "requirements.txt", "Pipfile",
+		"pom.xml", "build.gradle", "build.gradle.kts",
+		"Cargo.toml",
+		"composer.json",
+	}
+
+	for _, indicator := range indicators {
+		if _, err := os.Stat(filepath.Join(dir, indicator)); err == nil {
+			return 4
+		}
+	}
+
+	patterns := []string{"*.go", "*.py", "*.js", "*.ts", "*.java", "*.rs"}
+	for _, pattern := range patterns {
+		if matches, _ := filepath.Glob(filepath.Join(dir, pattern)); len(matches) > 0 {
+			return 4
+		}
+	}
+
+	return 0
+}
+
+// termHeuristic returns a default width based on the TERM variable.
+func termHeuristic() int {
+	termEnv := strings.ToLower(os.Getenv("TERM"))
+	if termEnv == "" {
+		return 0
+	}
+
+	if strings.Contains(termEnv, "vt52") {
+		return 2
+	}
+
+	if strings.Contains(termEnv, "xterm") ||
+		strings.Contains(termEnv, "screen") ||
+		strings.Contains(termEnv, "tmux") ||
+		strings.Contains(termEnv, "linux") ||
+		strings.Contains(termEnv, "ansi") ||
+		strings.Contains(termEnv, "rxvt") {
+		return TabWidthDefault
+	}
+
+	return 0
+}
+
+func clamp(w int) int {
+	if w <= 0 {
+		return 0
+	}
+	if w > 32 {
+		return 32
+	}
+	return w
+}
+
+var (
+	globalTab     *Tabinal
+	globalTabOnce sync.Once
+)
+
+// TabInstance returns the singleton Tabinal.
+func TabInstance() *Tabinal {
+	globalTabOnce.Do(func() {
+		globalTab = &Tabinal{}
+	})
+	return globalTab
+}
+
+// TabWidth returns the detected global tab width.
+func TabWidth() int {
+	return TabInstance().Size()
+}
+
+// SetTabWidth sets the global tab width.
+func SetTabWidth(w int) {
+	TabInstance().SetWidth(w)
+}
+
+func envInt(k string) int {
+	v := os.Getenv(k)
+	w, _ := strconv.Atoi(v)
+	return w
+}