Unify host and native filesystem acquisition

internal/engine/imports.go

@@ -4,9 +4,6 @@ import (
 	"bytes"
 	"errors"
 	"io/fs"
-	"os"
-	"path"
-	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -40,57 +37,83 @@ type importRoute struct {
 	locations []Location
 }
 
-type importTraversal struct {
-	rootPath string
-	root     *os.Root
-	limits   importLimits
-	rule     *VersionRule
+type importAccounting struct {
+	sources int
+	bytes   int64
+	nodes   int
+	entries int
+}
 
-	documents   []*document.Node
-	sources     []SourceInfo
-	active      map[string]int
-	visited     map[string]importRoute
-	stack       []importRoute
-	usedBytes   int64
-	usedNodes   int
-	usedEntries int
+type importTraversal struct {
+	access     *filesystemAccess
+	accounting *importAccounting
+	limits     importLimits
+	rule       *VersionRule
+
+	documents []*document.Node
+	sources   []SourceInfo
+	active    map[resourceIdentity]int
+	visited   map[resourceIdentity]importRoute
+	stack     []importRoute
 }
 
 func loadImportedDocuments(source Source, context *FilesystemContext, main parsedSource, rule *VersionRule, limits importLimits) (*composedDocument, []SourceInfo, []Diagnostic) {
+	if source.kind == sourceFilesystem {
+		access := newNativeAccess(source.namespace.filesystem, ".", source.namespace.token)
+		return loadImportedWithAccess(access, access.dir(source.path), source.path, main, rule, limits, &importAccounting{})
+	}
 	rootPath, basePath, mainPath, diagnostic := importFilesystem(source, context, main)
 	if diagnostic != nil {
 		return nil, sourceInfos(main.source), []Diagnostic{*diagnostic}
 	}
-	root, err := os.OpenRoot(rootPath)
+	access, err := openHostAccess(rootPath)
 	if err != nil {
 		diagnostic := globFilesystemDiagnostic(err, "configuration root could not be opened", Location{})
 		diagnostic.Primary = nil
 		return nil, sourceInfos(main.source), []Diagnostic{diagnostic}
 	}
+	return loadImportedWithAccess(access, basePath, mainPath, main, rule, limits, &importAccounting{})
+}
 
+func loadImportedWithAccess(access *filesystemAccess, basePath, mainPath string, main parsedSource, rule *VersionRule, limits importLimits, accounting *importAccounting) (*composedDocument, []SourceInfo, []Diagnostic) {
+	if !access.contains(basePath) || (mainPath != "" && !access.contains(mainPath)) {
+		_ = access.close()
+		return nil, sourceInfos(main.source), []Diagnostic{importDiagnostic(CodeImportOutsideRoot, "selected source and import base must stay inside the configuration root", nil)}
+	}
+	for _, directory := range []string{access.rootPath, basePath} {
+		info, err := access.stat(directory)
+		if err != nil || !info.IsDir() {
+			_ = access.close()
+			return nil, sourceInfos(main.source), []Diagnostic{importDiagnostic(CodeImportInvalid, "configuration root and import base must be directories", nil)}
+		}
+	}
 	mainInfo := cloneSourceInfo(*main.source)
 	if mainPath != "" {
 		mainInfo.Path = mainPath
 	}
+	accounting.sources++
+	accounting.bytes += main.bytes
+	accounting.nodes += countInputNodes(main.document)
 	state := importTraversal{
-		rootPath: rootPath, root: root, limits: limits, rule: rule,
+		access: access, accounting: accounting, limits: limits, rule: rule,
 		documents: make([]*document.Node, 0, 1),
 		sources:   []SourceInfo{mainInfo},
-		active:    make(map[string]int), visited: make(map[string]importRoute),
-		usedBytes: main.bytes, usedNodes: countInputNodes(main.document),
+		active:    make(map[resourceIdentity]int), visited: make(map[resourceIdentity]importRoute),
 	}
 	if diagnostic := state.checkInitialLimits(); diagnostic != nil {
-		_ = root.Close()
+		_ = access.close()
 		return nil, cloneSourceInfos(state.sources), []Diagnostic{*diagnostic}
 	}
 
 	mainIdentity := mainPath
+	mainKey := access.identity(mainPath)
 	if mainIdentity == "" {
 		mainIdentity = "<selected-source>"
+		mainKey = access.syntheticIdentity()
 	}
 	mainRoute := importRoute{canonical: mainIdentity}
-	state.active[mainIdentity] = 0
-	state.visited[mainIdentity] = mainRoute
+	state.active[mainKey] = 0
+	state.visited[mainKey] = mainRoute
 	state.stack = append(state.stack, mainRoute)
 	body, declarations, diagnostics := splitImportDirectives(main.document)
 	if len(diagnostics) == 0 {
@@ -98,7 +121,7 @@ func loadImportedDocuments(source Source, context *FilesystemContext, main parse
 		diagnostics = state.walkDeclarations(basePath, declarations, 0)
 	}
 
-	closeErr := root.Close()
+	closeErr := access.close()
 	if len(diagnostics) != 0 {
 		return nil, cloneSourceInfos(state.sources), diagnostics
 	}
@@ -107,22 +130,22 @@ func loadImportedDocuments(source Source, context *FilesystemContext, main parse
 	}
 	composed, diagnostics := composeDocuments(state.documents...)
 	if composed != nil {
-		composed.inputBytes = state.usedBytes
-		composed.inputNodes = state.usedNodes
+		composed.inputBytes = accounting.bytes
+		composed.inputNodes = accounting.nodes
 	}
 	return composed, cloneSourceInfos(state.sources), diagnostics
 }
 
 func (s *importTraversal) checkInitialLimits() *Diagnostic {
-	if s.limits.sources < 1 {
+	if s.accounting.sources > s.limits.sources {
 		value := importDiagnostic(CodeImportLimitExceeded, "configuration exceeds the source-count limit", nil)
 		return &value
 	}
-	if s.usedBytes > s.limits.bytes {
+	if s.accounting.bytes > s.limits.bytes {
 		value := importDiagnostic(CodeImportLimitExceeded, "configuration exceeds the aggregate byte limit", nil)
 		return &value
 	}
-	if s.usedNodes > s.limits.nodes {
+	if s.accounting.nodes > s.limits.nodes {
 		value := importDiagnostic(CodeImportLimitExceeded, "configuration exceeds the aggregate node limit", nil)
 		return &value
 	}
@@ -169,11 +192,11 @@ func (s *importTraversal) visitPath(basePath string, declaration importDeclarati
 		return []Diagnostic{importDiagnostic(CodeImportInvalid, "import path must be a nonempty slash-relative path without a network scheme", &location)}
 	}
 
-	candidate := filepath.Join(basePath, filepath.FromSlash(path.Clean(declaration.path)))
-	if !containedPath(s.rootPath, filepath.Clean(candidate)) {
+	candidate := s.access.join(basePath, declaration.path)
+	if !s.access.contains(candidate) {
 		return []Diagnostic{importDiagnostic(CodeImportOutsideRoot, "import target is outside the configuration root", &location)}
 	}
-	canonical, err := canonicalExistingPath(candidate)
+	canonical, err := s.access.canonical(candidate)
 	if err != nil {
 		if declaration.optional && errors.Is(err, fs.ErrNotExist) {
 			return nil
@@ -187,30 +210,30 @@ func (s *importTraversal) visitPath(basePath string, declaration importDeclarati
 		}
 		return []Diagnostic{importDiagnostic(code, message, &location)}
 	}
-	if !containedPath(s.rootPath, canonical) {
+	if !s.access.contains(canonical) {
 		return []Diagnostic{importDiagnostic(CodeImportOutsideRoot, "import target resolves outside the configuration root", &location)}
 	}
 
 	currentRoute := s.currentRoute(location)
-	if activeIndex, ok := s.active[canonical]; ok {
+	identity := s.access.identity(canonical)
+	if activeIndex, ok := s.active[identity]; ok {
 		cycle := append([]importRoute(nil), s.stack[activeIndex:]...)
 		return []Diagnostic{importCycleDiagnostic(canonical, location, cycle)}
 	}
-	if previous, ok := s.visited[canonical]; ok {
+	if previous, ok := s.visited[identity]; ok {
 		return []Diagnostic{importRepeatedDiagnostic(location, previous, currentRoute)}
 	}
-	if len(s.sources)+1 > s.limits.sources {
+	if s.accounting.sources+1 > s.limits.sources {
 		return []Diagnostic{importDiagnostic(CodeImportLimitExceeded, "configuration exceeds the source-count limit", &location)}
 	}
 
-	relative, err := filepath.Rel(s.rootPath, canonical)
-	if err != nil || filepath.IsAbs(relative) || relative == ".." || strings.HasPrefix(relative, ".."+string(filepath.Separator)) {
+	if _, err := s.access.relative(canonical); err != nil {
 		return []Diagnostic{importDiagnostic(CodeImportOutsideRoot, "import target could not be addressed inside the configuration root", &location)}
 	}
-	sourceID := "source-" + strconv.Itoa(len(s.sources)+1)
+	sourceID := "source-" + strconv.Itoa(s.accounting.sources+1)
 	info := SourceInfo{ID: sourceID, Label: declaration.path, Path: canonical, Layer: LayerBase, ImportedFrom: &location}
 	s.sources = append(s.sources, info)
-	data, skipped, diagnostic := s.readImport(relative, sourceID, declaration.optional)
+	data, skipped, diagnostic := s.readImport(canonical, sourceID, declaration.optional)
 	if diagnostic != nil {
 		return []Diagnostic{*diagnostic}
 	}
@@ -218,6 +241,7 @@ func (s *importTraversal) visitPath(basePath string, declaration importDeclarati
 		s.sources = s.sources[:len(s.sources)-1]
 		return nil
 	}
+	s.accounting.sources++
 
 	root, issues := yamladapter.Parse(bytes.NewReader(data), sourceID, yamladapter.Limits{
 		Depth: maxDocumentDepth, Nodes: maxDocumentNodes,
@@ -226,10 +250,10 @@ func (s *importTraversal) visitPath(basePath string, declaration importDeclarati
 		return parserDiagnostics(sourceID, issues)
 	}
 	nodeCount := countInputNodes(root)
-	if s.usedNodes+nodeCount > s.limits.nodes {
+	if s.accounting.nodes+nodeCount > s.limits.nodes {
 		return []Diagnostic{importDiagnostic(CodeImportLimitExceeded, "configuration exceeds the aggregate node limit", &location)}
 	}
-	s.usedNodes += nodeCount
+	s.accounting.nodes += nodeCount
 
 	body, declarations, diagnostics := splitImportDirectives(root)
 	if len(diagnostics) != 0 {
@@ -245,22 +269,22 @@ func (s *importTraversal) visitPath(basePath string, declaration importDeclarati
 
 	route := importRoute{canonical: canonical, locations: currentRoute.locations}
 	s.documents = append(s.documents, body)
-	s.active[canonical] = len(s.stack)
-	s.visited[canonical] = route
+	s.active[identity] = len(s.stack)
+	s.visited[identity] = route
 	s.stack = append(s.stack, route)
-	diagnostics = s.walkDeclarations(filepath.Dir(canonical), declarations, depth)
-	delete(s.active, canonical)
+	diagnostics = s.walkDeclarations(s.access.dir(canonical), declarations, depth)
+	delete(s.active, identity)
 	s.stack = s.stack[:len(s.stack)-1]
 	return diagnostics
 }
 
-func (s *importTraversal) readImport(relative, sourceID string, optional bool) ([]byte, bool, *Diagnostic) {
-	remaining := s.limits.bytes - s.usedBytes
+func (s *importTraversal) readImport(name, sourceID string, optional bool) ([]byte, bool, *Diagnostic) {
+	remaining := s.limits.bytes - s.accounting.bytes
 	limit := min(int64(maxSourceBytes), remaining)
 	if limit < 0 {
 		limit = 0
 	}
-	data, failure := readRegularFile(relative, s.root.Stat, s.root.Open, limit)
+	data, failure := readRegularFile(name, s.access.stat, s.access.open, limit)
 	if failure != nil {
 		if optional && failure.missingTarget {
 			return nil, true, nil
@@ -268,7 +292,7 @@ func (s *importTraversal) readImport(relative, sourceID string, optional bool) (
 		value := sourceReadDiagnostic(failure, sourceID, CodeImportLimitExceeded, "configuration exceeds a source or aggregate byte limit")
 		return nil, false, &value
 	}
-	s.usedBytes += int64(len(data))
+	s.accounting.bytes += int64(len(data))
 	return data, false, nil
 }