Preserve code samples and watcher state during file updates

internal/vault/links.go

@@ -7,7 +7,7 @@ import (
 )
 
 // RewriteAssetLinks 在笔记改名后，把正文中指向旧图片目录（oldBase.assets/）的链接改为新目录。
-// 覆盖行内链接/图片 `](…)`、引用定义 `[x]: …` 与 HTML `src="…"`，跳过围栏代码块和行内代码。
+// 覆盖行内链接/图片 `](…)`、引用定义 `[x]: …` 与 HTML `src="…"`，跳过代码块和行内代码。
 func RewriteAssetLinks(content []byte, oldBase, newBase string) []byte {
 	oldRaw := regexp.QuoteMeta(oldBase + AssetsExt + "/")
 	oldEsc := regexp.QuoteMeta(EscapeLinkPath(oldBase+AssetsExt) + "/")
@@ -18,24 +18,120 @@ func RewriteAssetLinks(content []byte, oldBase, newBase string) []byte {
 
 	lines := bytes.SplitAfter(content, []byte("\n"))
 	var fence []byte // 当前所在围栏代码块的围栏字符串，nil 表示不在代码块中
+	var containers []linkContainer
+	paragraph := false
 	for i, line := range lines {
-		trimmed := bytes.TrimLeft(line, " ")
+		// 分类时展开制表符，替换仍作用于原始字节，不重新序列化 Markdown。
+		body := bytes.TrimRight(expandLinkTabs(line), "\r\n")
+		matched := 0
+		for _, container := range containers {
+			indent := len(body) - len(bytes.TrimLeft(body, " "))
+			if container.quote {
+				if indent > 3 || indent == len(body) || body[indent] != '>' {
+					break
+				}
+				body = body[indent+1:]
+				if len(body) > 0 && body[0] == ' ' {
+					body = body[1:]
+				}
+			} else if indent == len(body) {
+				body = nil // 空行不结束列表容器。
+			} else if indent >= container.indent {
+				body = body[container.indent:]
+			} else {
+				break
+			}
+			matched++
+		}
+		if matched < len(containers) {
+			containers = containers[:matched]
+			fence = nil // 容器结束时，其内部未闭合的代码块也结束。
+			// 段落允许省略引用或列表前缀的续行，不能把其缩进误认成代码。
+		}
 		if fence != nil {
-			if bytes.HasPrefix(trimmed, fence) && len(bytes.TrimSpace(bytes.TrimLeft(trimmed, string(fence[:1])))) == 0 {
+			trimmed := bytes.TrimLeft(body, " ")
+			if len(body)-len(trimmed) <= 3 && bytes.HasPrefix(trimmed, fence) && len(bytes.TrimSpace(bytes.TrimLeft(trimmed, string(fence[:1])))) == 0 {
 				fence = nil
 			}
 			continue
 		}
-		if f := fenceOpen(line); f != nil {
+		// 新的引用或列表可以嵌套；列表的后续行按其内容起始列剥离缩进。
-			fence = f
+		for {
+			indent := len(body) - len(bytes.TrimLeft(body, " "))
+			if indent > 3 || indent == len(body) {
+				break
+			}
+			rest := body[indent:]
+			if rest[0] == '>' {
+				containers = append(containers, linkContainer{quote: true})
+				body = rest[1:]
+				if len(body) > 0 && body[0] == ' ' {
+					body = body[1:]
+				}
+			} else if paragraphBoundary.Match(rest) {
+				break // 分隔线优先于列表标记。
+			} else if marker := listMarker.Find(rest); marker != nil {
+				mark := bytes.TrimRight(marker, " ")
+				// 有序列表只有从 1 开始且非空时才能打断段落。
+				if paragraph && (len(marker) == len(rest) || (mark[0] >= '0' && mark[0] <= '9' && !bytes.Equal(mark[:len(mark)-1], []byte("1")))) {
+					break
+				}
+				padding := len(marker) - len(mark)
+				if padding == 0 || padding > 4 {
+					padding = 1
+				}
+				width := indent + len(mark) + padding
+				containers = append(containers, linkContainer{indent: width})
+				body = body[min(width, len(body)):]
+			} else {
+				break
+			}
+			paragraph = false
+		}
+		trimmed := bytes.TrimLeft(body, " ")
+		if len(trimmed) == 0 {
+			paragraph = false
 			continue
 		}
+		// 缩进代码不能打断已有段落，列表容器自身的缩进不计入这四列。
+		if len(body)-len(trimmed) >= 4 && !paragraph {
+			continue
+		}
+		if f := fenceOpen(body); f != nil {
+			fence = f
+			paragraph = false
+			continue
+		}
+		paragraph = !paragraphBoundary.Match(trimmed) && !refDef.Match(trimmed)
 		line = refDef.ReplaceAll(line, repl)
 		lines[i] = replaceOutsideCode(line, inline, repl)
 	}
 	return bytes.Join(lines, nil)
 }
 
+type linkContainer struct {
+	quote  bool
+	indent int
+}
+
+var listMarker = regexp.MustCompile(`^(?:[-+*]|[0-9]{1,9}[.)])(?: +|$)`)
+var paragraphBoundary = regexp.MustCompile(`^(?:#{1,6}(?: |$)|(?:\* *){3,}$|(?:_ *){3,}$|(?:- *){3,}$|[=-]+ *$)`)
+
+func expandLinkTabs(line []byte) []byte {
+	if !bytes.ContainsRune(line, '\t') {
+		return line
+	}
+	var out []byte
+	for _, ch := range line {
+		if ch == '\t' {
+			out = append(out, bytes.Repeat([]byte(" "), 4-len(out)%4)...)
+		} else {
+			out = append(out, ch)
+		}
+	}
+	return out
+}
+
 // fenceOpen 识别围栏代码块起始行（至多 3 个空格缩进，3 个以上 ` 或 ~），返回围栏字符串
 func fenceOpen(line []byte) []byte {
 	indent := len(line) - len(bytes.TrimLeft(line, " "))

internal/vault/links_test.go

@@ -0,0 +1,53 @@
+package vault
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestRewriteAssetLinksPreservesCodeBlocks(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		code string
+	}{
+		{"缩进", "    ![](a.assets/code.png)\n"},
+		{"制表符", "\t![](a.assets/code.png)\n"},
+		{"引用围栏", "> ```markdown\n> ![](a.assets/code.png)\n> ```\n"},
+		{"引用缩进", ">     ![](a.assets/code.png)\n"},
+		{"列表围栏", "- ```markdown\n  ![](a.assets/code.png)\n  ```\n"},
+		{"列表缩进", "- 项目\n\n      ![](a.assets/code.png)\n"},
+		{"有序列表缩进", "10. 项目\n\n        ![](a.assets/code.png)\n"},
+		{"引用内嵌列表", "> - ```markdown\n>   ![](a.assets/code.png)\n>   ```\n"},
+		{"围栏内四格关闭标记", "```markdown\n    ```\n![](a.assets/code.png)\n```\n"},
+		{"标题后缩进代码", "# 标题\n    ![](a.assets/code.png)\n"},
+		{"分隔线后缩进代码", "* * *\n    ![](a.assets/code.png)\n"},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			input := tc.code + "\n![](a.assets/real.png)\n"
+			want := tc.code + "\n![](b.assets/real.png)\n"
+			if got := string(RewriteAssetLinks([]byte(input), "a", "b")); got != want {
+				t.Fatalf("代码示例应保持原样，真实链接应更新:\n got %q\nwant %q", got, want)
+			}
+		})
+	}
+}
+
+func TestRewriteAssetLinksInContainersAndParagraphs(t *testing.T) {
+	for _, input := range []string{
+		"> ![](a.assets/real.png)\n",
+		"- ![](a.assets/real.png)\n",
+		"- 项目\n\n    ![](a.assets/real.png)\n",
+		"- 项目\n  - 子项\n    ![](a.assets/real.png)\n",
+		"段落\n    ![](a.assets/real.png)\n",
+		"> 段落\n    ![](a.assets/real.png)\n",
+		"- 段落\n![](a.assets/real.png)\n    ![](a.assets/real.png)\n",
+		"10. 项目\n\n    ![](a.assets/real.png)\n",
+		"- 项目\n  - 子项\n    ```markdown\n    ![](a.assets/code.png)\n    ```\n\n  ![](a.assets/real.png)\n",
+		"> ```markdown\n> ![](a.assets/code.png)\n\n![](a.assets/real.png)\n",
+	} {
+		want := strings.ReplaceAll(input, "a.assets/real.png", "b.assets/real.png")
+		if got := string(RewriteAssetLinks([]byte(input), "a", "b")); got != want {
+			t.Errorf("容器缩进与段落续行不应被当作代码:\n got %q\nwant %q", got, want)
+		}
+	}
+}

internal/watch/watch.go

@@ -4,6 +4,9 @@ package watch
 
 import (
 	"context"
+	"errors"
+	"fmt"
+	"io/fs"
 	"log/slog"
 	"os"
 	"path/filepath"
@@ -139,9 +142,12 @@ func (w *Watcher) scan() (map[string]fileState, error) {
 				st.rev = old.rev
 			} else {
 				data, err := os.ReadFile(abs)
-				if err != nil {
+				if errors.Is(err, fs.ErrNotExist) {
 					continue // 扫描期间被删除，下一轮会处理
 				}
+				if err != nil {
+					return nil, fmt.Errorf("读取笔记 %s 失败: %w", e.Path, err)
+				}
 				st.rev = vault.Rev(data)
 			}
 		}

internal/watch/watch_test.go

@@ -6,8 +6,65 @@ import (
 	"sort"
 	"strings"
 	"testing"
+
+	"github.com/fsnotify/fsnotify"
+
+	"rawmark/internal/events"
+	"rawmark/internal/vault"
 )
 
+func TestUnreadableNotePreservesSnapshot(t *testing.T) {
+	if os.Geteuid() == 0 {
+		t.Skip("权限回归需要以非 root 用户运行")
+	}
+	v, err := vault.Open(t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	p := filepath.Join(v.Root(), "note.md")
+	if err := os.WriteFile(p, []byte("原文"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	fw, err := fsnotify.NewWatcher()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer fw.Close()
+	scans := 0
+	hub := events.NewHub()
+	w := &Watcher{v: v, fw: fw, hub: hub, snap: map[string]fileState{}, watched: map[string]bool{}, onScan: func(map[string]string) { scans++ }}
+	w.snap, err = w.scan()
+	if err != nil {
+		t.Fatal(err)
+	}
+	old := w.snap["note.md"].rev
+	ch, cancel := hub.Subscribe()
+	defer cancel()
+	if err := os.WriteFile(p, []byte("修改后的较长正文"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Chmod(p, 0); err != nil {
+		t.Fatal(err)
+	}
+	defer os.Chmod(p, 0o644)
+	w.rescan()
+	if w.snap["note.md"].rev != old || scans != 0 {
+		t.Fatal("读取失败不能提交不完整快照或更新索引")
+	}
+	select {
+	case msg := <-ch:
+		t.Fatalf("读取失败不能广播删除事件: %s", msg)
+	default:
+	}
+	if err := os.Chmod(p, 0o644); err != nil {
+		t.Fatal(err)
+	}
+	w.rescan()
+	if w.snap["note.md"].rev == old || scans != 1 {
+		t.Fatal("恢复读取权限后应同步新版本")
+	}
+}
+
 func TestDiff(t *testing.T) {
 	root := t.TempDir()
 	if err := os.Mkdir(filepath.Join(root, "d"), 0o755); err != nil {