make validate optional and use structs for prefixes

internal/manifest/manifest.go

@@ -45,6 +45,8 @@ type Manifest struct {
 	db *jsonwall.DB
 }
 
+// Read loads a Manifest from a file without performing any validation. The file
+// is assumed to be both valid jsonwall and a valid Manifest (see [Validate]).
 func Read(absPath string) (manifest *Manifest, err error) {
 	defer func() {
 		if err != nil {
@@ -68,21 +70,24 @@ func Read(absPath string) (manifest *Manifest, err error) {
 	}
 
 	manifest = &Manifest{db: jsonwallDB}
-	err = validate(manifest)
-	if err != nil {
-		return nil, err
-	}
 	return manifest, nil
 }
 
-func (manifest *Manifest) IteratePath(prefix string, f func(Path) error) (err error) {
+func (manifest *Manifest) IteratePath(pathPrefix string, f func(Path) error) (err error) {
 	defer func() {
 		if err != nil {
 			err = fmt.Errorf("cannot read manifest: %s", err)
 		}
 	}()
 
-	iter, err := manifest.db.IteratePrefix(map[string]string{"kind": "path", "path": prefix})
+	prefix := struct {
+		Kind string `json:"kind"`
+		Path string `json:"path"`
+	}{
+		Kind: "path",
+		Path: pathPrefix,
+	}
+	iter, err := manifest.db.IteratePrefix(prefix)
 	if err != nil {
 		return err
 	}
@@ -132,7 +137,14 @@ func (manifest *Manifest) IterateSlices(pkgName string, f func(Slice) error) (er
 		}
 	}()
 
-	iter, err := manifest.db.IteratePrefix(map[string]string{"kind": "slice", "name": pkgName})
+	prefix := struct {
+		Kind string `json:"kind"`
+		Name string `json:"name"`
+	}{
+		Kind: "slice",
+		Name: pkgName,
+	}
+	iter, err := manifest.db.IteratePrefix(&prefix)
 	if err != nil {
 		return err
 	}
@@ -150,7 +162,10 @@ func (manifest *Manifest) IterateSlices(pkgName string, f func(Slice) error) (er
 	return nil
 }
 
-func validate(manifest *Manifest) (err error) {
+// Validate checks that the Manifest is valid. Note that to do that it has to
+// load practically the whole manifest into memory and unmarshall all the
+// entries.
+func Validate(manifest *Manifest) (err error) {
 	defer func() {
 		if err != nil {
 			err = fmt.Errorf(`invalid manifest: %s`, err)

internal/manifest/manifest_test.go

@@ -66,21 +66,21 @@ var manifestTests = []struct {
 {"jsonwall":"1.0","schema":"1.0","count":1}
 {"kind":"content","slice":"pkg1_manifest","path":"/manifest/manifest.wall"}
 `,
-		error: `cannot read manifest: invalid manifest: slice pkg1_manifest not found in slices`,
+		error: `invalid manifest: slice pkg1_manifest not found in slices`,
 	}, {
 		summary: "Package not found",
 		input: `
 {"jsonwall":"1.0","schema":"1.0","count":1}
 {"kind":"slice","name":"pkg1_manifest"}
 `,
-		error: `cannot read manifest: invalid manifest: package "pkg1" not found in packages`,
+		error: `invalid manifest: package "pkg1" not found in packages`,
 	}, {
 		summary: "Path not found in contents",
 		input: `
 {"jsonwall":"1.0","schema":"1.0","count":1}
 {"kind":"path","path":"/dir/","mode":"01777","slices":["pkg1_myslice"]}
 `,
-		error: `cannot read manifest: invalid manifest: path /dir/ has no matching entry in contents`,
+		error: `invalid manifest: path /dir/ has no matching entry in contents`,
 	}, {
 		summary: "Content and path have different slices",
 		input: `
@@ -90,7 +90,7 @@ var manifestTests = []struct {
 {"kind":"path","path":"/dir/","mode":"01777","slices":["pkg1_myslice"]}
 {"kind":"slice","name":"pkg1_myotherslice"}
 `,
-		error: `cannot read manifest: invalid manifest: path /dir/ and content have diverging slices: \["pkg1_myslice"\] != \["pkg1_myotherslice"\]`,
+		error: `invalid manifest: path /dir/ and content have diverging slices: \["pkg1_myslice"\] != \["pkg1_myotherslice"\]`,
 	}, {
 		summary: "Content not found in paths",
 		input: `
@@ -99,7 +99,7 @@ var manifestTests = []struct {
 {"kind":"package","name":"pkg1","version":"v1","sha256":"hash1","arch":"arch1"}
 {"kind":"slice","name":"pkg1_myslice"}
 `,
-		error: `cannot read manifest: invalid manifest: content path /dir/ has no matching entry in paths`,
+		error: `invalid manifest: content path /dir/ has no matching entry in paths`,
 	}}
 
 func (s *S) TestRun(c *C) {
@@ -126,6 +126,8 @@ func (s *S) TestRun(c *C) {
 		c.Assert(test.input, DeepEquals, orderedInput, Commentf("input jsonwall lines should be ordered"))
 
 		mfest, err := manifest.Read(manifestPath)
+		c.Assert(err, IsNil)
+		err = manifest.Validate(mfest)
 		if test.error != "" {
 			c.Assert(err, ErrorMatches, test.error)
 			continue