sourcemaps

internal/sourcemaps/store.go

@@ -1,11 +1,13 @@
 package sourcemaps
 
 import (
+	"encoding/base64"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"regexp"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -28,7 +30,76 @@ func New(dir string) (*Resolver, error) {
 	if err := os.MkdirAll(dir, 0750); err != nil {
 		return nil, err
 	}
-	return &Resolver{dir: dir, maps: make(map[string]*sm.Consumer)}, nil
+	r := &Resolver{dir: dir, maps: make(map[string]*sm.Consumer)}
+	r.load()
+	return r, nil
+}
+
+// fileName encodes release and source reversibly so maps can be reloaded
+// from disk after a restart.
+func fileName(release, source string) string {
+	enc := base64.RawURLEncoding
+	return enc.EncodeToString([]byte(release)) + "." + enc.EncodeToString([]byte(normalize(source))) + ".map"
+}
+
+func parseFileName(name string) (release, source string, ok bool) {
+	parts := strings.Split(strings.TrimSuffix(name, ".map"), ".")
+	if len(parts) != 2 || !strings.HasSuffix(name, ".map") {
+		return "", "", false
+	}
+	rel, err1 := base64.RawURLEncoding.DecodeString(parts[0])
+	src, err2 := base64.RawURLEncoding.DecodeString(parts[1])
+	if err1 != nil || err2 != nil {
+		return "", "", false
+	}
+	return string(rel), string(src), true
+}
+
+// load restores previously uploaded maps; unreadable or legacy-named files are skipped.
+func (r *Resolver) load() {
+	entries, err := os.ReadDir(r.dir)
+	if err != nil {
+		return
+	}
+	for _, e := range entries {
+		release, source, ok := parseFileName(e.Name())
+		if !ok || e.IsDir() {
+			continue
+		}
+		b, err := os.ReadFile(filepath.Join(r.dir, e.Name()))
+		if err != nil {
+			continue
+		}
+		consumer, err := sm.Parse(source+".map", b)
+		if err != nil {
+			continue
+		}
+		r.maps[key(release, source)] = consumer
+	}
+}
+
+// Entry describes one loaded source map.
+type Entry struct {
+	Release string `json:"release"`
+	Source  string `json:"source"`
+}
+
+// List returns every loaded map, sorted by release then source.
+func (r *Resolver) List() []Entry {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	out := make([]Entry, 0, len(r.maps))
+	for k := range r.maps {
+		release, source, _ := strings.Cut(k, "\x00")
+		out = append(out, Entry{Release: release, Source: source})
+	}
+	sort.Slice(out, func(i, j int) bool {
+		if out[i].Release != out[j].Release {
+			return out[i].Release < out[j].Release
+		}
+		return out[i].Source < out[j].Source
+	})
+	return out
 }
 
 func key(release, source string) string { return release + "\x00" + normalize(source) }
@@ -53,7 +124,7 @@ func (r *Resolver) Upload(release, source string, body io.Reader) error {
 	if err != nil {
 		return fmt.Errorf("invalid source map: %w", err)
 	}
-	name := filepath.Join(r.dir, safe(release)+"-"+safe(normalize(source))+".map")
+	name := filepath.Join(r.dir, fileName(release, source))
 	if err := os.WriteFile(name, b, 0600); err != nil {
 		return err
 	}
@@ -104,3 +175,67 @@ func (r *Resolver) ResolveStack(release, stack string) string {
 	}
 	return strings.Join(lines, "\n")
 }
+
+// Frame is one parsed stack frame, with original-source details when a map
+// for its file was uploaded. Status explains why a frame is or is not mapped:
+// "mapped", "no-release", "no-map" (no map uploaded for this file/release) or
+// "unmapped" (a map exists but has no mapping for this position).
+type Frame struct {
+	Raw      string `json:"raw"`
+	Function string `json:"function,omitempty"`
+	File     string `json:"file"`
+	Line     int    `json:"line"`
+	Column   int    `json:"column"`
+	Status   string `json:"status"`
+
+	Source     string   `json:"source,omitempty"`
+	Name       string   `json:"name,omitempty"`
+	SrcLine    int      `json:"srcLine,omitempty"`
+	SrcColumn  int      `json:"srcColumn,omitempty"`
+	Context    []string `json:"context,omitempty"`    // original source lines around SrcLine
+	ContextTop int      `json:"contextTop,omitempty"` // 1-based line number of Context[0]
+}
+
+const frameContext = 6
+
+// ResolveFrames parses every frame in the stack and maps it through the
+// uploaded source maps, including surrounding original source when the map
+// embeds sourcesContent.
+func (r *Resolver) ResolveFrames(release, stack string) []Frame {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	var frames []Frame
+	for _, line := range strings.Split(stack, "\n") {
+		m := frameRE.FindStringSubmatch(line)
+		if m == nil {
+			continue
+		}
+		ln, _ := strconv.Atoi(m[3])
+		col, _ := strconv.Atoi(m[4])
+		fn := strings.TrimSpace(strings.TrimSuffix(strings.TrimPrefix(strings.TrimSpace(m[1]), "at "), "("))
+		f := Frame{Raw: strings.TrimSpace(line), Function: fn, File: m[2], Line: ln, Column: col, Status: "mapped"}
+		switch consumer := r.maps[key(release, m[2])]; {
+		case release == "":
+			f.Status = "no-release"
+		case consumer == nil:
+			f.Status = "no-map"
+		default:
+			source, name, sl, sc, ok := consumer.Source(ln, col)
+			if !ok {
+				f.Status = "unmapped"
+				break
+			}
+			f.Source, f.Name, f.SrcLine, f.SrcColumn = source, name, sl, sc
+			if content := consumer.SourceContent(source); content != "" {
+				src := strings.Split(content, "\n")
+				top := max(sl-frameContext, 1)
+				bottom := min(sl+frameContext, len(src))
+				if top <= bottom {
+					f.Context, f.ContextTop = src[top-1:bottom], top
+				}
+			}
+		}
+		frames = append(frames, f)
+	}
+	return frames
+}

internal/sourcemaps/store_test.go

@@ -0,0 +1,24 @@
+package sourcemaps
+
+import (
+	"strings"
+	"testing"
+)
+
+const testMap = `{"version":3,"file":"a.js","sources":["src/a.ts"],"sourcesContent":["const a = 1\nthrow new Error('x')\n"],"names":[],"mappings":"AAAA;AACA"}`
+
+func TestReloadFromDisk(t *testing.T) {
+	dir := t.TempDir()
+	r, _ := New(dir)
+	if err := r.Upload("rel1", "https://h/assets/a.js", strings.NewReader(testMap)); err != nil {
+		t.Fatal(err)
+	}
+	r2, _ := New(dir) // simulates a restart
+	if l := r2.List(); len(l) != 1 || l[0].Release != "rel1" || l[0].Source != "/assets/a.js" {
+		t.Fatalf("list after reload = %+v", l)
+	}
+	frames := r2.ResolveFrames("rel1", "Error: x\n    at f (https://h/assets/a.js:2:1)")
+	if len(frames) != 1 || frames[0].Status != "mapped" || frames[0].Source != "src/a.ts" || len(frames[0].Context) == 0 {
+		t.Fatalf("frames = %+v", frames)
+	}
+}