vendor tsgo

tools/tsgo/internal/project/programcounter.go

@@ -0,0 +1,48 @@
+package project
+
+import (
+	"sync"
+
+	"github.com/microsoft/typescript-go/internal/compiler"
+)
+
+type programCounter struct {
+	mu   sync.Mutex
+	refs map[*compiler.Program]int32
+}
+
+// Ref increments the reference count for a program. If the program is not
+// yet tracked, it is added with a reference count of 1.
+func (c *programCounter) Ref(program *compiler.Program) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.refs == nil {
+		c.refs = make(map[*compiler.Program]int32)
+	}
+	c.refs[program]++
+}
+
+func (c *programCounter) Deref(program *compiler.Program) bool {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	count, ok := c.refs[program]
+	if !ok {
+		return false
+	}
+	count--
+	if count < 0 {
+		panic("program reference count went below zero")
+	}
+	if count == 0 {
+		delete(c.refs, program)
+		return true
+	}
+	c.refs[program] = count
+	return false
+}
+
+func (c *programCounter) Len() int {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return len(c.refs)
+}