Initial commit

pkg/openapi/diff.go

@@ -0,0 +1,63 @@
+package openapi
+
+import (
+	"bufio"
+	"io"
+	"strings"
+)
+
+// DiffBlock represents a single file change in a git diff.
+type DiffBlock struct {
+	File    string
+	Content string // The full diff content for this file
+}
+
+// DiffParser parses a stream of git diff output.
+type DiffParser struct {
+	onBlock func(DiffBlock)
+	current *DiffBlock
+	sb      strings.Builder
+}
+
+// NewDiffParser creates a new DiffParser.
+func NewDiffParser(onBlock func(DiffBlock)) *DiffParser {
+	return &DiffParser{onBlock: onBlock}
+}
+
+// Parse reads from r and calls onBlock for each completed diff block.
+func (p *DiffParser) Parse(r io.Reader) error {
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		p.Feed(scanner.Text())
+	}
+	p.Flush()
+	return scanner.Err()
+}
+
+// Feed processes a single line of diff output.
+func (p *DiffParser) Feed(line string) {
+	if strings.HasPrefix(line, "diff --git ") {
+		p.Flush()
+		p.current = &DiffBlock{}
+		// Extract file path from "diff --git a/path/to/file b/path/to/file"
+		parts := strings.Split(line, " ")
+		if len(parts) >= 4 {
+			p.current.File = strings.TrimPrefix(parts[3], "b/")
+		}
+	}
+
+	if p.current != nil {
+		p.sb.WriteString(line)
+		p.sb.WriteString("\n")
+	}
+}
+
+// Flush finalizes the current block and emits it.
+func (p *DiffParser) Flush() {
+	if p.current != nil {
+		p.current.Content = p.sb.String()
+		p.onBlock(*p.current)
+		p.current = nil
+		p.sb.Reset()
+	}
+}