internal/service: add support for didChangeWatchedFiles (hashicorp#790)

* internal/service: add support for didChangeWatchedFiles

Signed-off-by: danishprakash <grafitykoncept@gmail.com>

* Handle both directory and file URIs correctly

* Add tests

* account for file/dir deletions and creations too

* use filepath.Dir instead path.Dir to account for OS differences

Co-authored-by: Radek Simko <radek.simko@gmail.com>

internal/langserver/handlers/did_change_watched_files.go

@@ -0,0 +1,181 @@
+package handlers
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/creachadair/jrpc2"
+	"github.com/hashicorp/terraform-ls/internal/document"
+	"github.com/hashicorp/terraform-ls/internal/job"
+	"github.com/hashicorp/terraform-ls/internal/protocol"
+	lsp "github.com/hashicorp/terraform-ls/internal/protocol"
+	"github.com/hashicorp/terraform-ls/internal/terraform/ast"
+	"github.com/hashicorp/terraform-ls/internal/uri"
+)
+
+func (svc *service) DidChangeWatchedFiles(ctx context.Context, params lsp.DidChangeWatchedFilesParams) error {
+	var ids job.IDs
+
+	for _, change := range params.Changes {
+		rawURI := string(change.URI)
+
+		rawPath, err := uri.PathFromURI(rawURI)
+		if err != nil {
+			svc.logger.Printf("error parsing %q: %s", rawURI, err)
+			continue
+		}
+
+		if change.Type == protocol.Deleted {
+			// We don't know whether file or dir is being deleted
+			// 1st we just blindly try to look it up as a directory
+			_, err = svc.modStore.ModuleByPath(rawPath)
+			if err == nil {
+				svc.removeIndexedModule(ctx, rawURI)
+				continue
+			}
+
+			// 2nd we try again assuming it is a file
+			parentDir := filepath.Dir(rawPath)
+			_, err = svc.modStore.ModuleByPath(parentDir)
+			if err != nil {
+				svc.logger.Printf("error finding module (%q deleted): %s", parentDir, err)
+				continue
+			}
+
+			// and check the parent directory still exists
+			fi, err := os.Stat(parentDir)
+			if err != nil {
+				if os.IsNotExist(err) {
+					// if not, we remove the indexed module
+					svc.removeIndexedModule(ctx, rawURI)
+					continue
+				}
+				svc.logger.Printf("error checking existence (%q deleted): %s", parentDir, err)
+				continue
+			}
+			if !fi.IsDir() {
+				svc.logger.Printf("error: %q (deleted) is not a directory", parentDir)
+				continue
+			}
+
+			// if the parent directory exists, we just need to
+			// reparse the module after a file was deleted from it
+			dirHandle := document.DirHandleFromPath(parentDir)
+			jobIds, err := svc.parseAndDecodeModule(dirHandle)
+			if err != nil {
+				svc.logger.Printf("error parsing module (%q deleted): %s", rawURI, err)
+				continue
+			}
+
+			ids = append(ids, jobIds...)
+		}
+
+		if change.Type == protocol.Changed {
+			ph, err := modHandleFromRawOsPath(ctx, rawPath)
+			if err != nil {
+				if err == ErrorSkip {
+					continue
+				}
+				svc.logger.Printf("error (%q changed): %s", rawURI, err)
+				continue
+			}
+
+			_, err = svc.modStore.ModuleByPath(ph.DirHandle.Path())
+			if err != nil {
+				svc.logger.Printf("error finding module (%q changed): %s", rawURI, err)
+				continue
+			}
+
+			jobIds, err := svc.parseAndDecodeModule(ph.DirHandle)
+			if err != nil {
+				svc.logger.Printf("error parsing module (%q changed): %s", rawURI, err)
+				continue
+			}
+
+			ids = append(ids, jobIds...)
+		}
+
+		if change.Type == protocol.Created {
+			ph, err := modHandleFromRawOsPath(ctx, rawPath)
+			if err != nil {
+				if err == ErrorSkip {
+					continue
+				}
+				svc.logger.Printf("error (%q created): %s", rawURI, err)
+				continue
+			}
+
+			if ph.IsDir {
+				err = svc.stateStore.WalkerPaths.EnqueueDir(ph.DirHandle)
+				if err != nil {
+					jrpc2.ServerFromContext(ctx).Notify(ctx, "window/showMessage", &lsp.ShowMessageParams{
+						Type: lsp.Warning,
+						Message: fmt.Sprintf("Ignoring new folder %s: %s."+
+							" This is most likely bug, please report it.", rawURI, err),
+					})
+					continue
+				}
+			} else {
+				jobIds, err := svc.parseAndDecodeModule(ph.DirHandle)
+				if err != nil {
+					svc.logger.Printf("error parsing module (%q created): %s", rawURI, err)
+					continue
+				}
+
+				ids = append(ids, jobIds...)
+			}
+		}
+	}
+
+	err := svc.stateStore.JobStore.WaitForJobs(ctx, ids...)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func modHandleFromRawOsPath(ctx context.Context, rawPath string) (*parsedModuleHandle, error) {
+	fi, err := os.Stat(rawPath)
+	if err != nil {
+		return nil, err
+	}
+
+	// URI can either be a file or a directory based on the LSP spec.
+	if fi.IsDir() {
+		return &parsedModuleHandle{
+			DirHandle: document.DirHandleFromPath(rawPath),
+			IsDir:     true,
+		}, nil
+	}
+
+	if !ast.IsModuleFilename(fi.Name()) && !ast.IsVarsFilename(fi.Name()) {
+		jrpc2.ServerFromContext(ctx).Notify(ctx, "window/showMessage", &lsp.ShowMessageParams{
+			Type: lsp.Warning,
+			Message: fmt.Sprintf("Unable to update %q: filetype not supported. "+
+				"This is likely a bug which should be reported.", rawPath),
+		})
+		return nil, ErrorSkip
+	}
+
+	docHandle := document.HandleFromPath(rawPath)
+	return &parsedModuleHandle{
+		DirHandle: docHandle.Dir,
+		IsDir:     false,
+	}, nil
+}
+
+type parsedModuleHandle struct {
+	DirHandle document.DirHandle
+	IsDir     bool
+}
+
+var ErrorSkip = errSkip{}
+
+type errSkip struct{}
+
+func (es errSkip) Error() string {
+	return "skip"
+}