chore: add agent endpoint for querying file system (#16736)

Closes https://github.com/coder/internal/issues/382

agent/ls_internal_test.go

@@ -0,0 +1,207 @@
+package agent
+
+import (
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestListFilesNonExistentDirectory(t *testing.T) {
+	t.Parallel()
+
+	query := LSRequest{
+		Path:       []string{"idontexist"},
+		Relativity: LSRelativityHome,
+	}
+	_, err := listFiles(query)
+	require.ErrorIs(t, err, os.ErrNotExist)
+}
+
+func TestListFilesPermissionDenied(t *testing.T) {
+	t.Parallel()
+
+	if runtime.GOOS == "windows" {
+		t.Skip("creating an unreadable-by-user directory is non-trivial on Windows")
+	}
+
+	home, err := os.UserHomeDir()
+	require.NoError(t, err)
+
+	tmpDir := t.TempDir()
+
+	reposDir := filepath.Join(tmpDir, "repos")
+	err = os.Mkdir(reposDir, 0o000)
+	require.NoError(t, err)
+
+	rel, err := filepath.Rel(home, reposDir)
+	require.NoError(t, err)
+
+	query := LSRequest{
+		Path:       pathToArray(rel),
+		Relativity: LSRelativityHome,
+	}
+	_, err = listFiles(query)
+	require.ErrorIs(t, err, os.ErrPermission)
+}
+
+func TestListFilesNotADirectory(t *testing.T) {
+	t.Parallel()
+
+	home, err := os.UserHomeDir()
+	require.NoError(t, err)
+
+	tmpDir := t.TempDir()
+
+	filePath := filepath.Join(tmpDir, "file.txt")
+	err = os.WriteFile(filePath, []byte("content"), 0o600)
+	require.NoError(t, err)
+
+	rel, err := filepath.Rel(home, filePath)
+	require.NoError(t, err)
+
+	query := LSRequest{
+		Path:       pathToArray(rel),
+		Relativity: LSRelativityHome,
+	}
+	_, err = listFiles(query)
+	require.ErrorContains(t, err, "is not a directory")
+}
+
+func TestListFilesSuccess(t *testing.T) {
+	t.Parallel()
+
+	tc := []struct {
+		name       string
+		baseFunc   func(t *testing.T) string
+		relativity LSRelativity
+	}{
+		{
+			name: "home",
+			baseFunc: func(t *testing.T) string {
+				home, err := os.UserHomeDir()
+				require.NoError(t, err)
+				return home
+			},
+			relativity: LSRelativityHome,
+		},
+		{
+			name: "root",
+			baseFunc: func(*testing.T) string {
+				if runtime.GOOS == "windows" {
+					return ""
+				}
+				return "/"
+			},
+			relativity: LSRelativityRoot,
+		},
+	}
+
+	// nolint:paralleltest // Not since Go v1.22.
+	for _, tc := range tc {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			base := tc.baseFunc(t)
+			tmpDir := t.TempDir()
+
+			reposDir := filepath.Join(tmpDir, "repos")
+			err := os.Mkdir(reposDir, 0o755)
+			require.NoError(t, err)
+
+			downloadsDir := filepath.Join(tmpDir, "Downloads")
+			err = os.Mkdir(downloadsDir, 0o755)
+			require.NoError(t, err)
+
+			textFile := filepath.Join(tmpDir, "file.txt")
+			err = os.WriteFile(textFile, []byte("content"), 0o600)
+			require.NoError(t, err)
+
+			var queryComponents []string
+			// We can't get an absolute path relative to empty string on Windows.
+			if runtime.GOOS == "windows" && base == "" {
+				queryComponents = pathToArray(tmpDir)
+			} else {
+				rel, err := filepath.Rel(base, tmpDir)
+				require.NoError(t, err)
+				queryComponents = pathToArray(rel)
+			}
+
+			query := LSRequest{
+				Path:       queryComponents,
+				Relativity: tc.relativity,
+			}
+			resp, err := listFiles(query)
+			require.NoError(t, err)
+
+			require.Equal(t, tmpDir, resp.AbsolutePathString)
+			require.ElementsMatch(t, []LSFile{
+				{
+					Name:               "repos",
+					AbsolutePathString: reposDir,
+					IsDir:              true,
+				},
+				{
+					Name:               "Downloads",
+					AbsolutePathString: downloadsDir,
+					IsDir:              true,
+				},
+				{
+					Name:               "file.txt",
+					AbsolutePathString: textFile,
+					IsDir:              false,
+				},
+			}, resp.Contents)
+		})
+	}
+}
+
+func TestListFilesListDrives(t *testing.T) {
+	t.Parallel()
+
+	if runtime.GOOS != "windows" {
+		t.Skip("skipping test on non-Windows OS")
+	}
+
+	query := LSRequest{
+		Path:       []string{},
+		Relativity: LSRelativityRoot,
+	}
+	resp, err := listFiles(query)
+	require.NoError(t, err)
+	require.Contains(t, resp.Contents, LSFile{
+		Name:               "C:\\",
+		AbsolutePathString: "C:\\",
+		IsDir:              true,
+	})
+
+	query = LSRequest{
+		Path:       []string{"C:\\"},
+		Relativity: LSRelativityRoot,
+	}
+	resp, err = listFiles(query)
+	require.NoError(t, err)
+
+	query = LSRequest{
+		Path:       resp.AbsolutePath,
+		Relativity: LSRelativityRoot,
+	}
+	resp, err = listFiles(query)
+	require.NoError(t, err)
+	// System directory should always exist
+	require.Contains(t, resp.Contents, LSFile{
+		Name:               "Windows",
+		AbsolutePathString: "C:\\Windows",
+		IsDir:              true,
+	})
+
+	query = LSRequest{
+		// Network drives are not supported.
+		Path:       []string{"\\sshfs\\work"},
+		Relativity: LSRelativityRoot,
+	}
+	resp, err = listFiles(query)
+	require.ErrorContains(t, err, "drive")
+}