Adding walk functionality

Adding tests

Move over to LandonTClipp afero branch until issue is fixed

Loop over every algorithm

There are a certain class of tests that should behave the same for each
type of algorithm, so create a loop that simply passes in a different
algorithm each time and run the same tests for each.

.mockery.yaml

@@ -0,0 +1,4 @@
+quiet: False
+all: True
+inpackage: True
+testonly: True

errors.go

@@ -1,7 +1,15 @@
 package pathlib
 
-import "github.com/pkg/errors"
+import "fmt"
 
 var (
-	ErrDoesNotImplement = errors.Errorf("doesn't implement required interface")
+	// ErrDoesNotImplement indicates that the afero filesystem doesn't
+	// implement the required interface.
+	ErrDoesNotImplement = fmt.Errorf("doesn't implement required interface")
+	// ErrInfoIsNil indicates that a nil os.FileInfo object was provided
+	ErrInfoIsNil = fmt.Errorf("provided os.Info object was nil")
+	// ErrInvalidAlgorithm specifies that an unknown algorithm was given for Walk
+	ErrInvalidAlgorithm = fmt.Errorf("invalid algorithm specified")
+	// ErrStopWalk indicates to the Walk function that the walk should be aborted
+	ErrStopWalk = fmt.Errorf("stop filesystem walk")
 )

file.go

@@ -1,6 +1,6 @@
 package pathlib
 
-import "github.com/spf13/afero"
+import "github.com/LandonTClipp/afero"
 
 // File represents a file in the filesystem. It inherits the afero.File interface
 // but might also include additional functionality.

go.mod

@@ -3,7 +3,9 @@ module github.com/chigopher/pathlib
 go 1.14
 
 require (
+	github.com/LandonTClipp/afero v1.3.6-0.20200907052150-97f9d166c7a3
 	github.com/pkg/errors v0.9.1
-	github.com/spf13/afero v1.3.2
+	github.com/rs/zerolog v1.18.0
 	github.com/stretchr/testify v1.6.1
+	github.com/vektra/mockery/v2 v2.1.0 // indirect
 )

path.go

@@ -8,7 +8,7 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
-	"github.com/spf13/afero"
+	"github.com/LandonTClipp/afero"
 )
 
 // Path is an object that represents a path
@@ -221,11 +221,6 @@ func (p *Path) SafeWriteReader(r io.Reader) error {
 	return afero.SafeWriteReader(p.Fs(), p.Path(), r)
 }
 
-// Walk walks path, using the given filepath.WalkFunc to handle each
-func (p *Path) Walk(walkFn filepath.WalkFunc) error {
-	return afero.Walk(p.Fs(), p.Path(), walkFn)
-}
-
 // WriteFile writes the given data to the path (if possible). If the file exists,
 // the file is truncated. If the file is a directory, or the path doesn't exist,
 // an error is returned.

path_test.go

@@ -12,7 +12,7 @@ import (
 	"testing"
 	"time"
 
-	"github.com/spf13/afero"
+	"github.com/LandonTClipp/afero"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"

walk.go

@@ -0,0 +1,217 @@
+package pathlib
+
+import (
+	"errors"
+	"fmt"
+	"os"
+)
+
+// WalkOpts is the struct that defines how a walk should be performed
+type WalkOpts struct {
+	// Depth defines how far down a directory we should recurse. A value of -1 means
+	// infinite depth. 0 means only the direct children of root will be returned, etc.
+	Depth int
+
+	// WalkAlgorithm specifies the algoritm that the Walk() function should use to
+	// traverse the directory.
+	WalkAlgorithm string
+
+	// FollowSymlinks defines whether symlinks should be dereferenced or not. If True,
+	// the symlink itself will never be returned to WalkFunc, but rather whatever it
+	// points to. Warning!!! You are exposing yourself to substantial risk by setting this
+	// to True. Here be dragons!
+	FollowSymlinks bool
+
+	// Size of the FIFO queue used when doing a breadth-first search
+	FIFOQueueSize int
+}
+
+// DefaultWalkOpts returns the default WalkOpts struct used when
+// walking a directory.
+func DefaultWalkOpts() *WalkOpts {
+	return &WalkOpts{
+		Depth:          -1,
+		WalkAlgorithm:  AlgorithmBasic(),
+		FollowSymlinks: false,
+		FIFOQueueSize:  100,
+	}
+}
+
+func AlgorithmDepthFirst() string {
+	return "depth-first"
+}
+
+func AlgorithmBasic() string {
+	return "basic"
+}
+
+// Walk is an object that handles walking through a directory tree
+type Walk struct {
+	Opts *WalkOpts
+	root *Path
+}
+
+// NewWalk returns a new Walk struct with default values applied
+func NewWalk(root *Path) (*Walk, error) {
+	return NewWalkWithOpts(root, DefaultWalkOpts())
+}
+
+// NewWalkWithOpts returns a Walk object with the given WalkOpts applied
+func NewWalkWithOpts(root *Path, opts *WalkOpts) (*Walk, error) {
+	if root == nil {
+		return nil, fmt.Errorf("root path can't be nil")
+	}
+	if opts == nil {
+		return nil, fmt.Errorf("opts can't be nil")
+	}
+	return &Walk{
+		Opts: opts,
+		root: root,
+	}, nil
+}
+
+func (w *Walk) maxDepthReached(currentDepth int) bool {
+	if w.Opts.Depth >= 0 && currentDepth > w.Opts.Depth {
+		return true
+	}
+	return false
+}
+
+type dfsObjectInfo struct {
+	path *Path
+	info os.FileInfo
+	err  error
+}
+
+func (w *Walk) walkDFS(walkFn WalkFunc, root *Path, currentDepth int) error {
+	if w.maxDepthReached(currentDepth) {
+		return nil
+	}
+
+	var nonDirectories []*dfsObjectInfo
+
+	if err := w.iterateImmediateChildren(root, func(child *Path, info os.FileInfo, encounteredErr error) error {
+		// Since we are doing depth-first, we have to first recurse through all the directories,
+		// and save all non-directory objects so we can defer handling at a later time.
+		if IsDir(info) {
+			if err := w.walkDFS(walkFn, child, currentDepth+1); err != nil {
+				return err
+			}
+			if err := walkFn(child, info, encounteredErr); err != nil {
+				return err
+			}
+		} else {
+			nonDirectories = append(nonDirectories, &dfsObjectInfo{
+				path: child,
+				info: info,
+				err:  encounteredErr,
+			})
+		}
+		return nil
+	}); err != nil {
+		return err
+	}
+
+	// Iterate over all non-directory objects
+	for _, nonDir := range nonDirectories {
+		if err := walkFn(nonDir.path, nonDir.info, nonDir.err); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// iterateImmediateChildren is a function that handles discovering root's immediate children,
+// and will run the algorithm function for every child. The algorithm function is essentially
+// what differentiates how each walk behaves, and determines what actions to take given a
+// certain child.
+func (w *Walk) iterateImmediateChildren(root *Path, algorithmFunction WalkFunc) error {
+	children, err := root.ReadDir()
+	if err != nil {
+		return err
+	}
+
+	var info os.FileInfo
+	for _, child := range children {
+		if child.Path() == root.Path() {
+			continue
+		}
+		if w.Opts.FollowSymlinks {
+			info, err = child.Stat()
+			isSymlink, err := IsSymlink(info)
+			if err != nil {
+				return err
+			}
+			if isSymlink {
+				child, err = child.ResolveAll()
+				if err != nil {
+					return err
+				}
+			}
+
+		} else {
+			info, _, err = child.Lstat()
+		}
+
+		if info == nil {
+			if err != nil {
+				return err
+			}
+			return ErrInfoIsNil
+		}
+
+		if algoErr := algorithmFunction(child, info, err); algoErr != nil {
+			return algoErr
+		}
+	}
+	return nil
+}
+
+func (w *Walk) walkBasic(walkFn WalkFunc, root *Path, currentDepth int) error {
+	if w.maxDepthReached(currentDepth) {
+		return nil
+	}
+
+	err := w.iterateImmediateChildren(root, func(child *Path, info os.FileInfo, encounteredErr error) error {
+		if IsDir(info) {
+			if err := w.walkBasic(walkFn, child, currentDepth+1); err != nil {
+				return err
+			}
+		}
+
+		if err := walkFn(child, info, encounteredErr); err != nil {
+			return err
+		}
+		return nil
+	})
+
+	return err
+}
+
+// WalkFunc is the function provided to the Walk function for each directory.
+type WalkFunc func(path *Path, info os.FileInfo, err error) error
+
+// Walk walks the directory using the algorithm specified in the configuration.
+func (w *Walk) Walk(walkFn WalkFunc) error {
+
+	switch w.Opts.WalkAlgorithm {
+	case AlgorithmBasic():
+		if err := w.walkBasic(walkFn, w.root, 0); err != nil {
+			if errors.Is(err, ErrStopWalk) {
+				return nil
+			}
+			return err
+		}
+		return nil
+	case AlgorithmDepthFirst():
+		if err := w.walkDFS(walkFn, w.root, 0); err != nil {
+			if errors.Is(err, ErrStopWalk) {
+				return nil
+			}
+			return err
+		}
+		return nil
+	default:
+		return ErrInvalidAlgorithm
+	}
+}