add HasPath() to Resolver interface

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

syft/source/all_layers_resolver.go

@@ -5,12 +5,10 @@ import (
 	"fmt"
 	"io"
 
-	"github.com/anchore/stereoscope/pkg/filetree"
-
-	"github.com/anchore/syft/internal/log"
-
 	"github.com/anchore/stereoscope/pkg/file"
+	"github.com/anchore/stereoscope/pkg/filetree"
 	"github.com/anchore/stereoscope/pkg/image"
+	"github.com/anchore/syft/internal/log"
 )
 
 var _ Resolver = (*AllLayersResolver)(nil)
@@ -37,6 +35,18 @@ func NewAllLayersResolver(img *image.Image) (*AllLayersResolver, error) {
 	}, nil
 }
 
+// HasPath indicates if the given path exists in the underlying source.
+func (r *AllLayersResolver) HasPath(path string) bool {
+	p := file.Path(path)
+	for _, layerIdx := range r.layers {
+		tree := r.img.Layers[layerIdx].Tree
+		if tree.HasPath(p) {
+			return true
+		}
+	}
+	return false
+}
+
 func (r *AllLayersResolver) fileByRef(ref file.Reference, uniqueFileIDs file.ReferenceSet, layerIdx int) ([]file.Reference, error) {
 	uniqueFiles := make([]file.Reference, 0)
 

syft/source/all_layers_resolver_test.go

@@ -13,9 +13,10 @@ type resolution struct {
 
 func TestAllLayersResolver_FilesByPath(t *testing.T) {
 	cases := []struct {
-		name        string
-		linkPath    string
-		resolutions []resolution
+		name                 string
+		linkPath             string
+		resolutions          []resolution
+		forcePositiveHasPath bool
 	}{
 		{
 			name:     "link with previous data",
@@ -66,14 +67,17 @@ func TestAllLayersResolver_FilesByPath(t *testing.T) {
 			},
 		},
 		{
-			name:        "dead link",
-			linkPath:    "/link-dead",
-			resolutions: []resolution{},
+			name:                 "dead link",
+			linkPath:             "/link-dead",
+			resolutions:          []resolution{},
+			forcePositiveHasPath: true,
 		},
 		{
 			name:        "ignore directories",
 			linkPath:    "/bin",
 			resolutions: []resolution{},
+			// directories don't resolve BUT do exist
+			forcePositiveHasPath: true,
 		},
 	}
 	for _, c := range cases {
@@ -86,6 +90,17 @@ func TestAllLayersResolver_FilesByPath(t *testing.T) {
 				t.Fatalf("could not create resolver: %+v", err)
 			}
 
+			hasPath := resolver.HasPath(c.linkPath)
+			if !c.forcePositiveHasPath {
+				if len(c.resolutions) > 0 && !hasPath {
+					t.Errorf("expected HasPath() to indicate existance, but did not")
+				} else if len(c.resolutions) == 0 && hasPath {
+					t.Errorf("expeced HasPath() to NOT indicate existance, but does")
+				}
+			} else if !hasPath {
+				t.Errorf("expected HasPath() to indicate existance, but did not (force path)")
+			}
+
 			refs, err := resolver.FilesByPath(c.linkPath)
 			if err != nil {
 				t.Fatalf("could not use resolver: %+v", err)

syft/source/directory_resolver.go

@@ -19,27 +19,37 @@ type DirectoryResolver struct {
 	Path string
 }
 
+func (r DirectoryResolver) requestPath(userPath string) string {
+	fullPath := userPath
+	if filepath.IsAbs(fullPath) {
+		// a path relative to root should be prefixed with the resolvers directory path, otherwise it should be left as is
+		fullPath = path.Join(r.Path, fullPath)
+	}
+	return fullPath
+}
+
+// HasPath indicates if the given path exists in the underlying source.
+func (r *DirectoryResolver) HasPath(userPath string) bool {
+	_, err := os.Stat(r.requestPath(userPath))
+	return !os.IsNotExist(err)
+}
+
 // Stringer to represent a directory path data source
-func (s DirectoryResolver) String() string {
-	return fmt.Sprintf("dir:%s", s.Path)
+func (r DirectoryResolver) String() string {
+	return fmt.Sprintf("dir:%s", r.Path)
 }
 
 // FilesByPath returns all file.References that match the given paths from the directory.
-func (s DirectoryResolver) FilesByPath(userPaths ...string) ([]Location, error) {
+func (r DirectoryResolver) FilesByPath(userPaths ...string) ([]Location, error) {
 	var references = make([]Location, 0)
 
 	for _, userPath := range userPaths {
-		userStrPath := userPath
-
-		if filepath.IsAbs(userStrPath) {
-			// a path relative to root should be prefixed with the resolvers directory path, otherwise it should be left as is
-			userStrPath = path.Join(s.Path, userStrPath)
-		}
+		userStrPath := r.requestPath(userPath)
 		fileMeta, err := os.Stat(userStrPath)
 		if os.IsNotExist(err) {
 			continue
 		} else if err != nil {
-			log.Errorf("path (%s) is not valid: %v", userStrPath, err)
+			log.Errorf("path (%r) is not valid: %v", userStrPath, err)
 		}
 
 		// don't consider directories
@@ -54,11 +64,11 @@ func (s DirectoryResolver) FilesByPath(userPaths ...string) ([]Location, error)
 }
 
 // FilesByGlob returns all file.References that match the given path glob pattern from any layer in the image.
-func (s DirectoryResolver) FilesByGlob(patterns ...string) ([]Location, error) {
+func (r DirectoryResolver) FilesByGlob(patterns ...string) ([]Location, error) {
 	result := make([]Location, 0)
 
 	for _, pattern := range patterns {
-		pathPattern := path.Join(s.Path, pattern)
+		pathPattern := path.Join(r.Path, pattern)
 		pathMatches, err := doublestar.Glob(pathPattern)
 		if err != nil {
 			return nil, err
@@ -84,8 +94,8 @@ func (s DirectoryResolver) FilesByGlob(patterns ...string) ([]Location, error) {
 // RelativeFileByPath fetches a single file at the given path relative to the layer squash of the given reference.
 // This is helpful when attempting to find a file that is in the same layer or lower as another file. For the
 // DirectoryResolver, this is a simple path lookup.
-func (s *DirectoryResolver) RelativeFileByPath(_ Location, path string) *Location {
-	paths, err := s.FilesByPath(path)
+func (r *DirectoryResolver) RelativeFileByPath(_ Location, path string) *Location {
+	paths, err := r.FilesByPath(path)
 	if err != nil {
 		return nil
 	}
@@ -97,7 +107,7 @@ func (s *DirectoryResolver) RelativeFileByPath(_ Location, path string) *Locatio
 }
 
 // MultipleFileContentsByLocation returns the file contents for all file.References relative a directory.
-func (s DirectoryResolver) MultipleFileContentsByLocation(locations []Location) (map[Location]io.ReadCloser, error) {
+func (r DirectoryResolver) MultipleFileContentsByLocation(locations []Location) (map[Location]io.ReadCloser, error) {
 	refContents := make(map[Location]io.ReadCloser)
 	for _, location := range locations {
 		refContents[location] = file.NewDeferredReadCloser(location.Path)
@@ -107,6 +117,6 @@ func (s DirectoryResolver) MultipleFileContentsByLocation(locations []Location)
 
 // FileContentsByLocation fetches file contents for a single file reference relative to a directory.
 // If the path does not exist an error is returned.
-func (s DirectoryResolver) FileContentsByLocation(location Location) (io.ReadCloser, error) {
+func (r DirectoryResolver) FileContentsByLocation(location Location) (io.ReadCloser, error) {
 	return file.NewDeferredReadCloser(location.Path), nil
 }

syft/source/directory_resolver_test.go

@@ -6,11 +6,12 @@ import (
 
 func TestDirectoryResolver_FilesByPath(t *testing.T) {
 	cases := []struct {
-		name     string
-		root     string
-		input    string
-		expected string
-		refCount int
+		name                 string
+		root                 string
+		input                string
+		expected             string
+		refCount             int
+		forcePositiveHasPath bool
 	}{
 		{
 			name:     "finds a file (relative)",
@@ -47,15 +48,28 @@ func TestDirectoryResolver_FilesByPath(t *testing.T) {
 			refCount: 1,
 		},
 		{
-			name:     "directories ignored",
-			root:     "./test-fixtures/",
-			input:    "/image-symlinks",
-			refCount: 0,
+			name:                 "directories ignored",
+			root:                 "./test-fixtures/",
+			input:                "/image-symlinks",
+			refCount:             0,
+			forcePositiveHasPath: true,
 		},
 	}
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
 			resolver := DirectoryResolver{c.root}
+
+			hasPath := resolver.HasPath(c.input)
+			if !c.forcePositiveHasPath {
+				if c.refCount != 0 && !hasPath {
+					t.Errorf("expected HasPath() to indicate existance, but did not")
+				} else if c.refCount == 0 && hasPath {
+					t.Errorf("expeced HasPath() to NOT indicate existance, but does")
+				}
+			} else if !hasPath {
+				t.Errorf("expected HasPath() to indicate existance, but did not (force path)")
+			}
+
 			refs, err := resolver.FilesByPath(c.input)
 			if err != nil {
 				t.Fatalf("could not use resolver: %+v, %+v", err, refs)

syft/source/image_squash_resolver.go

@@ -4,9 +4,8 @@ import (
 	"fmt"
 	"io"
 
-	"github.com/anchore/stereoscope/pkg/filetree"
-
 	"github.com/anchore/stereoscope/pkg/file"
+	"github.com/anchore/stereoscope/pkg/filetree"
 	"github.com/anchore/stereoscope/pkg/image"
 )
 
@@ -25,6 +24,11 @@ func NewImageSquashResolver(img *image.Image) (*ImageSquashResolver, error) {
 	return &ImageSquashResolver{img: img}, nil
 }
 
+// HasPath indicates if the given path exists in the underlying source.
+func (r *ImageSquashResolver) HasPath(path string) bool {
+	return r.img.SquashedTree().HasPath(file.Path(path))
+}
+
 // FilesByPath returns all file.References that match the given paths within the squashed representation of the image.
 func (r *ImageSquashResolver) FilesByPath(paths ...string) ([]Location, error) {
 	uniqueFileIDs := file.NewFileReferenceSet()

syft/source/image_squash_resolver_test.go

@@ -8,10 +8,11 @@ import (
 
 func TestImageSquashResolver_FilesByPath(t *testing.T) {
 	cases := []struct {
-		name         string
-		linkPath     string
-		resolveLayer uint
-		resolvePath  string
+		name                 string
+		linkPath             string
+		resolveLayer         uint
+		resolvePath          string
+		forcePositiveHasPath bool
 	}{
 		{
 			name:         "link with previous data",
@@ -42,11 +43,15 @@ func TestImageSquashResolver_FilesByPath(t *testing.T) {
 			linkPath:     "/link-dead",
 			resolveLayer: 8,
 			resolvePath:  "",
+			// the path should exist, even if the link is dead
+			forcePositiveHasPath: true,
 		},
 		{
 			name:        "ignore directories",
 			linkPath:    "/bin",
 			resolvePath: "",
+			// the path should exist, even if we ignore it
+			forcePositiveHasPath: true,
 		},
 		{
 			name:         "parent is a link (with overridden data)",
@@ -65,6 +70,17 @@ func TestImageSquashResolver_FilesByPath(t *testing.T) {
 				t.Fatalf("could not create resolver: %+v", err)
 			}
 
+			hasPath := resolver.HasPath(c.linkPath)
+			if !c.forcePositiveHasPath {
+				if c.resolvePath != "" && !hasPath {
+					t.Errorf("expected HasPath() to indicate existance, but did not")
+				} else if c.resolvePath == "" && hasPath {
+					t.Errorf("expeced HasPath() to NOT indicate existance, but does")
+				}
+			} else if !hasPath {
+				t.Errorf("expected HasPath() to indicate existance, but did not (force path)")
+			}
+
 			refs, err := resolver.FilesByPath(c.linkPath)
 			if err != nil {
 				t.Fatalf("could not use resolver: %+v", err)

syft/source/mock_resolver.go

@@ -28,6 +28,16 @@ func NewMockResolverForPaths(paths ...string) *MockResolver {
 	return &MockResolver{Locations: locations}
 }
 
+// HasPath indicates if the given path exists in the underlying source.
+func (r MockResolver) HasPath(path string) bool {
+	for _, l := range r.Locations {
+		if l.Path == path {
+			return true
+		}
+	}
+	return false
+}
+
 // String returns the string representation of the MockResolver.
 func (r MockResolver) String() string {
 	return fmt.Sprintf("mock:(%s,...)", r.Locations[0].Path)

syft/source/resolver.go

@@ -20,8 +20,10 @@ type ContentResolver interface {
 	// TODO: we should consider refactoring to return a set of io.Readers or file.Openers instead of the full contents themselves (allow for optional buffering).
 }
 
-// FileResolver knows how to get file.References for given string paths and globs
+// FileResolver knows how to get a Location for given string paths and globs
 type FileResolver interface {
+	// HasPath indicates if the given path exists in the underlying source.
+	HasPath(path string) bool
 	// FilesByPath fetches a set of file references which have the given path (for an image, there may be multiple matches)
 	FilesByPath(paths ...string) ([]Location, error)
 	// FilesByGlob fetches a set of file references which the given glob matches