feat: Add text document hover; Improvements

doc-values/base-value.go

@@ -10,6 +10,7 @@ type Value interface {
 	GetTypeDescription() []string
 	CheckIsValid(value string) []*InvalidValue
 	FetchCompletions(line string, cursor uint32) []protocol.CompletionItem
+	FetchHoverInfo(line string, cursor uint32) []string
 }
 
 type InvalidValue struct {

doc-values/value-array.go

@@ -114,17 +114,55 @@ func (v ArrayValue) CheckIsValid(value string) []*InvalidValue {
 	return errors
 }
 
-func (v ArrayValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
-	if cursor == 0 {
-		return v.SubValue.FetchCompletions(line, cursor)
+func (v ArrayValue) getCurrentValue(line string, cursor uint32) (string, uint32) {
+	if line == "" {
+		return line, cursor
 	}
 
-	relativePosition, found := utils.FindPreviousCharacter(line, v.Separator, int(cursor-1))
+	if cursor == uint32(len(line)) {
+		cursor--
+	}
+
+	var start uint32
+	var end uint32
+
+	relativePosition, found := utils.FindPreviousCharacter(
+		line,
+		v.Separator,
+		int(cursor),
+	)
 
 	if found {
-		line = line[uint32(relativePosition+1):]
-		cursor -= uint32(relativePosition + 1)
+		// +1 to skip the separator
+		start = uint32(relativePosition + 1)
+	} else {
+		start = 0
 	}
 
-	return v.SubValue.FetchCompletions(line, cursor)
+	relativePosition, found = utils.FindNextCharacter(
+		line,
+		v.Separator,
+		int(cursor),
+	)
+
+	if found {
+		// -1 to skip the separator
+		end = uint32(relativePosition - 1)
+	} else {
+		end = uint32(len(line))
+	}
+
+	return line[start:end], cursor - start
+}
+
+func (v ArrayValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
+	value, cursor := v.getCurrentValue(line, cursor)
+
+	return v.SubValue.FetchCompletions(value, cursor)
+}
+
+func (v ArrayValue) FetchHoverInfo(line string, cursor uint32) []string {
+	value, cursor := v.getCurrentValue(line, cursor)
+
+	return v.SubValue.FetchHoverInfo(value, cursor)
 }

doc-values/value-custom.go

@@ -21,7 +21,7 @@ type CustomValue struct {
 }
 
 func (v CustomValue) GetTypeDescription() []string {
-	return []string{"Custom"}
+	return v.FetchValue(EmptyValueContextInstance).GetTypeDescription()
 }
 
 func (v CustomValue) CheckIsValid(value string) []*InvalidValue {
@@ -31,3 +31,7 @@ func (v CustomValue) CheckIsValid(value string) []*InvalidValue {
 func (v CustomValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
 	return v.FetchValue(EmptyValueContextInstance).FetchCompletions(line, cursor)
 }
+
+func (v CustomValue) FetchHoverInfo(line string, cursor uint32) []string {
+	return v.FetchValue(EmptyValueContextInstance).FetchHoverInfo(line, cursor)
+}

doc-values/value-enum.go

@@ -118,3 +118,14 @@ func (v EnumValue) FetchCompletions(line string, cursor uint32) []protocol.Compl
 
 	return completions
 }
+func (v EnumValue) FetchHoverInfo(line string, cursor uint32) []string {
+	for _, value := range v.Values {
+		if value.InsertText == line {
+			return []string{
+				value.Documentation,
+			}
+		}
+	}
+
+	return []string{}
+}

doc-values/value-gid.go

@@ -2,6 +2,7 @@ package docvalues
 
 import (
 	"config-lsp/utils"
+	"fmt"
 	"strconv"
 
 	protocol "github.com/tliron/glsp/protocol_3_16"
@@ -126,3 +127,26 @@ func (v GIDValue) FetchCompletions(line string, cursor uint32) []protocol.Comple
 
 	return completions
 }
+func (v GIDValue) FetchHoverInfo(line string, cursor uint32) []string {
+	uid, err := strconv.Atoi(line)
+
+	if err != nil {
+		return []string{}
+	}
+
+	infos, err := fetchGroupInfo()
+
+	if err != nil {
+		return []string{}
+	}
+
+	for _, info := range infos {
+		if info.GID == strconv.Itoa(uid) {
+			return []string{
+				fmt.Sprintf("Group %s; GID: %s", info.Name, info.GID),
+			}
+		}
+	}
+
+	return []string{}
+}

doc-values/value-ip-address.go

@@ -2,6 +2,7 @@ package docvalues
 
 import (
 	"config-lsp/utils"
+	"fmt"
 	net "net/netip"
 
 	protocol "github.com/tliron/glsp/protocol_3_16"
@@ -162,3 +163,47 @@ func (v IPAddressValue) FetchCompletions(line string, cursor uint32) []protocol.
 
 	return []protocol.CompletionItem{}
 }
+
+func (v IPAddressValue) FetchHoverInfo(line string, cursor uint32) []string {
+	if v.AllowRange {
+		ip, err := net.ParsePrefix(line)
+
+		if err != nil {
+			return []string{}
+		}
+
+		if ip.Addr().IsPrivate() {
+			return []string{
+				fmt.Sprintf("%s (Private IP Address)", ip.String()),
+			}
+		} else if ip.Addr().IsLoopback() {
+			return []string{
+				fmt.Sprintf("%s (Loopback IP Address)", ip.String()),
+			}
+		} else {
+			return []string{
+				fmt.Sprintf("%s (Public IP Address)", ip.String()),
+			}
+		}
+	} else {
+		ip, err := net.ParseAddr(line)
+
+		if err != nil {
+			return []string{}
+		}
+
+		if ip.IsPrivate() {
+			return []string{
+				fmt.Sprintf("%s (Private IP Address)", ip.String()),
+			}
+		} else if ip.IsLoopback() {
+			return []string{
+				fmt.Sprintf("%s (Loopback IP Address)", ip.String()),
+			}
+		} else {
+			return []string{
+				fmt.Sprintf("%s (Public IP Address)", ip.String()),
+			}
+		}
+	}
+}

doc-values/value-key-enum-assignment.go

@@ -136,6 +136,35 @@ func (v KeyEnumAssignmentValue) FetchEnumCompletions() []protocol.CompletionItem
 	return completions
 }
 
+type selectedValue string
+
+const (
+	keySelected   selectedValue = "key"
+	valueSelected selectedValue = "value"
+)
+
+func (v KeyEnumAssignmentValue) getValueAtCursor(line string, cursor uint32) (string, *selectedValue, uint32) {
+	relativePosition, found := utils.FindPreviousCharacter(line, v.Separator, int(cursor))
+
+	if found {
+		// Value found
+		selected := valueSelected
+		return line[uint32(relativePosition+1):], &selected, cursor - uint32(relativePosition)
+	}
+
+	selected := keySelected
+
+	// Key, let's check for the separator
+	relativePosition, found = utils.FindNextCharacter(line, v.Separator, int(cursor))
+
+	if found {
+		return line[:uint32(relativePosition)], &selected, cursor
+	}
+
+	// No separator, so we can just return the whole line
+	return line, &selected, cursor
+}
+
 func (v KeyEnumAssignmentValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
 	if cursor == 0 {
 		return v.FetchEnumCompletions()
@@ -160,3 +189,50 @@ func (v KeyEnumAssignmentValue) FetchCompletions(line string, cursor uint32) []p
 		return v.FetchEnumCompletions()
 	}
 }
+
+func (v KeyEnumAssignmentValue) FetchHoverInfo(line string, cursor uint32) []string {
+	if len(v.CheckIsValid(line)) != 0 {
+		return []string{}
+	}
+
+	value, selected, cursor := v.getValueAtCursor(line, cursor)
+
+	if selected == nil {
+		return []string{}
+	}
+
+	if *selected == keySelected {
+		// Search for enum documentation
+		enums := utils.KeysOfMap(v.Values)
+		key := value
+
+		for _, enum := range enums {
+			if enum.InsertText == value {
+				return []string{
+					fmt.Sprintf("## `%s%s<value>`", key, v.Separator),
+					enum.Documentation,
+				}
+			}
+		}
+	} else if *selected == valueSelected {
+		// Search for value documentation
+		// - 1 to remove the separator
+		key := strings.SplitN(line, v.Separator, 2)[0]
+		checkValue, found := v.getValue(key)
+
+		if !found {
+			return []string{}
+		}
+
+		info := (*checkValue).FetchHoverInfo(value, cursor)
+
+		return append(
+			[]string{
+				fmt.Sprintf("## `%s%s%s`", key, v.Separator, value),
+			},
+			info...,
+		)
+	}
+
+	return []string{}
+}

doc-values/value-key-value-assignment.go

@@ -120,3 +120,49 @@ func (v KeyValueAssignmentValue) FetchCompletions(line string, cursor uint32) []
 		return v.Key.FetchCompletions(line, cursor)
 	}
 }
+
+func (v KeyValueAssignmentValue) getValueAtCursor(line string, cursor uint32) (string, *selectedValue, uint32) {
+	relativePosition, found := utils.FindPreviousCharacter(line, v.Separator, int(cursor))
+
+	if found {
+		// Value found
+		selected := valueSelected
+		return line[:uint32(relativePosition)], &selected, cursor - uint32(relativePosition)
+	}
+
+	selected := keySelected
+
+	// Key, let's check for the separator
+	relativePosition, found = utils.FindNextCharacter(line, v.Separator, int(cursor))
+
+	if found {
+		return line[:uint32(relativePosition)], &selected, cursor
+	}
+
+	// No separator, so we can just return the whole line
+	return line, &selected, cursor
+}
+
+func (v KeyValueAssignmentValue) FetchHoverInfo(line string, cursor uint32) []string {
+	if len(v.CheckIsValid(line)) != 0 {
+		return []string{}
+	}
+
+	value, selected, cursor := v.getValueAtCursor(line, cursor)
+
+	if selected == nil {
+		return []string{}
+	}
+
+	if *selected == keySelected {
+		// Get key documentation
+		return v.Key.FetchHoverInfo(value, cursor)
+	} else if *selected == valueSelected {
+		// Get for value documentation
+		key := strings.SplitN(line, v.Separator, 2)[0]
+
+		return v.getValue(key).FetchHoverInfo(value, cursor)
+	}
+
+	return []string{}
+}

doc-values/value-mask-mode.go

@@ -1,8 +1,10 @@
 package docvalues
 
 import (
-	protocol "github.com/tliron/glsp/protocol_3_16"
+	"fmt"
 	"regexp"
+
+	protocol "github.com/tliron/glsp/protocol_3_16"
 )
 
 type MaskModeInvalidError struct{}
@@ -121,3 +123,44 @@ func (v MaskModeValue) FetchCompletions(line string, cursor uint32) []protocol.C
 		},
 	}
 }
+
+func getMaskRepresentation(digit uint8) string {
+	switch digit {
+	case 0:
+		return "---"
+	case 1:
+		return "--x"
+	case 2:
+		return "-w-"
+	case 3:
+		return "-wx"
+	case 4:
+		return "r--"
+	case 5:
+		return "r-x"
+	case 6:
+		return "rw-"
+	case 7:
+		return "rwx"
+	}
+
+	return ""
+}
+
+func (v MaskModeValue) FetchHoverInfo(line string, cursor uint32) []string {
+	if !maskModePattern.MatchString(line) {
+		return []string{}
+	}
+
+	mask := line
+
+	firstDigit := uint8(mask[1] - 48)
+	secondDigit := uint8(mask[2] - 48)
+	thridDigit := uint8(mask[3] - 48)
+
+	representation := getMaskRepresentation(firstDigit) + getMaskRepresentation(secondDigit) + getMaskRepresentation(thridDigit)
+
+	return []string{
+		fmt.Sprintf("%s (%s)", mask, representation),
+	}
+}

doc-values/value-number.go

@@ -76,3 +76,7 @@ func (v NumberValue) CheckIsValid(value string) []*InvalidValue {
 func (v NumberValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
 	return []protocol.CompletionItem{}
 }
+
+func (v NumberValue) FetchHoverInfo(line string, cursor uint32) []string {
+	return []string{}
+}

doc-values/value-or.go

@@ -77,3 +77,16 @@ func (v OrValue) FetchCompletions(line string, cursor uint32) []protocol.Complet
 
 	return completions
 }
+
+func (v OrValue) FetchHoverInfo(line string, cursor uint32) []string {
+	for _, subValue := range v.Values {
+		valueErrors := subValue.CheckIsValid(line)
+
+		if len(valueErrors) == 0 {
+			// Found
+			return subValue.FetchHoverInfo(line, cursor)
+		}
+	}
+
+	return []string{}
+}

doc-values/value-path.go

@@ -81,3 +81,7 @@ func (v PathValue) CheckIsValid(value string) []*InvalidValue {
 func (v PathValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
 	return []protocol.CompletionItem{}
 }
+
+func (v PathValue) FetchHoverInfo(line string, cursor uint32) []string {
+	return []string{}
+}

doc-values/value-power-of-two.go

@@ -75,3 +75,7 @@ func (v PowerOfTwoValue) FetchCompletions(line string, cursor uint32) []protocol
 		},
 	)
 }
+
+func (v PowerOfTwoValue) FetchHoverInfo(line string, cursor uint32) []string {
+	return []string{}
+}

doc-values/value-prefix.go

@@ -3,6 +3,8 @@ package docvalues
 import (
 	"config-lsp/utils"
 	"fmt"
+	"strings"
+
 	protocol "github.com/tliron/glsp/protocol_3_16"
 )
 
@@ -49,3 +51,17 @@ func (v PrefixWithMeaningValue) FetchCompletions(line string, cursor uint32) []p
 
 	return append(prefixCompletions, v.SubValue.FetchCompletions(line, cursor)...)
 }
+
+func (v PrefixWithMeaningValue) FetchHoverInfo(line string, cursor uint32) []string {
+	for _, prefix := range v.Prefixes {
+		if strings.HasPrefix(line, prefix.Prefix) {
+			return append([]string{
+				fmt.Sprintf("Prefix: _%s_ -> %s", prefix.Prefix, prefix.Meaning),
+			},
+				v.SubValue.FetchHoverInfo(line[1:], cursor)...,
+			)
+		}
+	}
+
+	return v.SubValue.FetchHoverInfo(line[1:], cursor)
+}

doc-values/value-regex.go

@@ -40,3 +40,9 @@ func (v RegexValue) CheckIsValid(value string) []*InvalidValue {
 func (v RegexValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
 	return []protocol.CompletionItem{}
 }
+
+func (v RegexValue) FetchHoverInfo(line string, cursor uint32) []string {
+	return []string{
+		fmt.Sprintf("Pattern: `%s`", v.Regex.String()),
+	}
+}

doc-values/value-string.go

@@ -48,3 +48,7 @@ func (v StringValue) CheckIsValid(value string) []*InvalidValue {
 func (v StringValue) FetchCompletions(line string, cursor uint32) []protocol.CompletionItem {
 	return []protocol.CompletionItem{}
 }
+
+func (v StringValue) FetchHoverInfo(line string, cursor uint32) []string {
+	return []string{}
+}

doc-values/value-uid.go

@@ -127,3 +127,27 @@ func (v UIDValue) FetchCompletions(line string, cursor uint32) []protocol.Comple
 
 	return completions
 }
+
+func (v UIDValue) FetchHoverInfo(line string, cursor uint32) []string {
+	uid, err := strconv.Atoi(line)
+
+	if err != nil {
+		return []string{}
+	}
+
+	infos, err := fetchPasswdInfo()
+
+	if err != nil {
+		return []string{}
+	}
+
+	for _, info := range infos {
+		if info.UID == strconv.Itoa(uid) {
+			return []string{
+				fmt.Sprintf("User %s; ID: %s:%s; ~:%s", info.Name, info.UID, info.GID, info.HomePath),
+			}
+		}
+	}
+
+	return []string{}
+}

doc-values/value-umask.go

@@ -110,3 +110,7 @@ func (v UmaskValue) FetchCompletions(line string, cursor uint32) []protocol.Comp
 		},
 	}
 }
+
+func (v UmaskValue) FetchHoverInfo(line string, cursor uint32) []string {
+	return []string{}
+}

handlers/fstab/hover-fields.go

@@ -0,0 +1,92 @@
+package fstab
+
+import protocol "github.com/tliron/glsp/protocol_3_16"
+
+var SpecHoverField = protocol.Hover{
+	Contents: protocol.MarkupContent{
+		Kind: protocol.MarkupKindMarkdown,
+		Value: `## The first field (fs_spec).
+This field describes the block special device, remote filesystem or filesystem image for loop device to be mounted or swap file or swap device to be enabled.
+
+For ordinary mounts, it will hold (a link to) a block special device node (as created by mknod(2)) for the device to be mounted, like /dev/cdrom or /dev/sdb7. For NFS mounts, this field is <host>:<dir>,
+e.g., knuth.aeb.nl:/. For filesystems with no storage, any string can be used, and will show up in df(1) output, for example. Typical usage is proc for procfs; mem, none, or tmpfs for tmpfs. Other special filesystems, like udev and sysfs, are typically not listed in fstab.
+
+LABEL=<label> or UUID=<uuid> may be given instead of a device name. This is the recommended method, as device names are often a coincidence of hardware detection order, and can change when other disks are added or removed. For example, 'LABEL=Boot' or 'UUID=3e6be9de-8139-11d1-9106-a43f08d823a6'. (Use a filesystem-specific tool like e2label(8), xfs_admin(8), or fatlabel(8) to set LABELs on filesystems).
+
+It’s also possible to use PARTUUID= and PARTLABEL=. These partitions identifiers are supported for example for GUID Partition Table (GPT).
+
+See mount(8), blkid(8) or lsblk(8) for more details about device identifiers.
+
+Note that mount(8) uses UUIDs as strings. The string representation of the UUID should be based on lower case characters. But when specifying the volume ID of FAT or NTFS file systems upper case characters are used (e.g UUID="A40D-85E7" or UUID="61DB7756DB7779B3").`,
+	},
+}
+
+var MountPointHoverField = protocol.Hover{
+	Contents: protocol.MarkupContent{
+		Kind: protocol.MarkupKindMarkdown,
+		Value: `## The second field (fs_file).
+This field describes the mount point (target) for the filesystem. For swap area, this field should be specified as 'none'. If the name of the mount point contains spaces or tabs these can be escaped as '\040' and '\011' respectively.`,
+	},
+}
+
+var FileSystemTypeField = protocol.Hover{
+	Contents: protocol.MarkupContent{
+		Kind: protocol.MarkupKindMarkdown,
+		Value: `## The third field (fs_vfstype).
+This field describes the type of the filesystem. Linux supports many filesystem types: ext4, xfs, btrfs, f2fs, vfat, ntfs, hfsplus, tmpfs, sysfs, proc, iso9660, udf, squashfs, nfs, cifs, and many more. For more details, see mount(8).
+
+An entry swap denotes a file or partition to be used for swapping, cf. swapon(8). An entry none is useful for bind or move mounts.
+
+More than one type may be specified in a comma-separated list.
+
+mount(8) and umount(8) support filesystem subtypes. The subtype is defined by '.subtype' suffix. For example 'fuse.sshfs'. It’s recommended to use subtype notation rather than add any prefix to the first fstab field (for example 'sshfs#example.com' is deprecated).`,
+	},
+}
+
+var MountOptionsField = protocol.Hover{
+	Contents: protocol.MarkupContent{
+		Kind: protocol.MarkupKindMarkdown,
+		Value: `## The fourth field (fs_mntops).
+This field describes the mount options associated with the filesystem.
+
+It is formatted as a comma-separated list of options and is optional for mount(8) or swapon(8). The usual convention is to use at least "defaults" keyword there.
+
+It usually contains the type of mount (ro or rw, the default is rw), plus any additional options appropriate to the filesystem type (including performance-tuning options). For details, see mount(8) or swapon(8).
+
+Basic filesystem-independent options are:
+
+defaults
+   use default options. The default depends on the kernel and the filesystem. mount(8) does not have any hardcoded set of default options. The kernel default is usually rw, suid, dev, exec, auto, nouser, and async.
+
+noauto
+   do not mount when mount -a is given (e.g., at boot time)
+
+user
+   allow a user to mount
+
+owner
+   allow device owner to mount
+
+comment
+   or x-<name> for use by fstab-maintaining programs
+
+nofail
+   do not report errors for this device if it does not exist.`,
+	},
+}
+
+var FreqHoverField = protocol.Hover{
+	Contents: protocol.MarkupContent{
+		Kind: protocol.MarkupKindMarkdown,
+		Value: `## The fifth field (fs_freq).
+This field is used by dump(8) to determine which filesystems need to be dumped. Defaults to zero (don’t dump) if not present.`,
+	},
+}
+
+var PassHoverField = protocol.Hover{
+	Contents: protocol.MarkupContent{
+		Kind: protocol.MarkupKindMarkdown,
+		Value: `## The sixth field (fs_passno).
+This field is used by fsck(8) to determine the order in which filesystem checks are done at boot time. The root filesystem should be specified with a fs_passno of 1. Other filesystems should have a fs_passno of 2. Filesystems within a drive will be checked sequentially, but filesystems on different drives will be checked at the same time to utilize parallelism available in the hardware. Defaults to zero (don’t check the filesystem) if not present.`,
+	},
+}

handlers/fstab/parser.go

@@ -12,8 +12,9 @@ import (
 	protocol "github.com/tliron/glsp/protocol_3_16"
 )
 
-var ignoreLinePattern = regexp.MustCompile(`^\s*(#|$)`)
-var whitespacePattern = regexp.MustCompile(`\s+`)
+var commentPattern = regexp.MustCompile(`^\s*#`)
+var ignoreLinePattern = regexp.MustCompile(`^\s*$`)
+var whitespacePattern = regexp.MustCompile(`\S+`)
 
 type MalformedLineError struct{}
 
@@ -76,12 +77,12 @@ func (f FstabFields) String() string {
 	)
 }
 
-type FstabEntry struct {
+type FstabLine struct {
 	Line   uint32
 	Fields FstabFields
 }
 
-func (e *FstabEntry) CheckIsValid() []protocol.Diagnostic {
+func (e *FstabLine) CheckIsValid() []protocol.Diagnostic {
 	diagnostics := make([]protocol.Diagnostic, 0)
 
 	if e.Fields.Spec != nil {
@@ -165,7 +166,7 @@ func (e *FstabEntry) CheckIsValid() []protocol.Diagnostic {
 	return diagnostics
 }
 
-func (e FstabEntry) GetFieldAtPosition(cursor uint32) FstabField {
+func (e FstabLine) GetFieldAtPosition(cursor uint32) FstabField {
 	if e.Fields.Spec == nil || (cursor >= e.Fields.Spec.Start && cursor <= e.Fields.Spec.End) {
 		return FstabFieldSpec
 	}
@@ -182,6 +183,7 @@ func (e FstabEntry) GetFieldAtPosition(cursor uint32) FstabField {
 		return FstabFieldOptions
 	}
 
+	println(fmt.Sprintf("cursor: %v, freq: %v", cursor, e.Fields.Freq))
 	if e.Fields.Freq == nil || (cursor >= e.Fields.Freq.Start && cursor <= e.Fields.Freq.End) {
 		return FstabFieldFreq
 	}
@@ -189,12 +191,24 @@ func (e FstabEntry) GetFieldAtPosition(cursor uint32) FstabField {
 	return FstabFieldPass
 }
 
+type FstabEntryType string
+
+const (
+	FstabEntryTypeLine    FstabEntryType = "line"
+	FstabEntryTypeComment FstabEntryType = "comment"
+)
+
+type FstabEntry struct {
+	Type FstabEntryType
+	Line FstabLine
+}
+
 type FstabParser struct {
 	entries []FstabEntry
 }
 
 func (p *FstabParser) AddLine(line string, lineNumber int) error {
-	fields := whitespacePattern.Split(line, -1)
+	fields := whitespacePattern.FindAllStringIndex(line, -1)
 
 	if len(fields) == 0 {
 		return MalformedLineError{}
@@ -209,95 +223,84 @@ func (p *FstabParser) AddLine(line string, lineNumber int) error {
 
 	switch len(fields) {
 	case 6:
-		value := fields[5]
-		start := uint32(strings.Index(line, value))
-
-		if start == 0 {
-			start = uint32(len(line))
-		}
+		field := fields[5]
+		start := uint32(field[0])
+		end := uint32(field[1])
 
 		pass = &Field{
-			Value: fields[5],
+			Value: line[start:end],
 			Start: start,
-			End:   start + uint32(len(value)),
+			End:   end,
 		}
 		fallthrough
 	case 5:
-		value := fields[4]
-		start := uint32(strings.Index(line, value))
-
-		if start == 0 {
-			start = uint32(len(line))
-		}
+		field := fields[4]
+		start := uint32(field[0])
+		end := uint32(field[1])
 
 		freq = &Field{
-			Value: value,
+			Value: line[start:end],
 			Start: start,
-			End:   start + uint32(len(value)),
+			End:   end,
 		}
 		fallthrough
 	case 4:
-		value := fields[3]
-		start := uint32(strings.Index(line, value))
-
-		if start == 0 {
-			start = uint32(len(line))
-		}
+		field := fields[3]
+		start := uint32(field[0])
+		end := uint32(field[1])
 
 		options = &Field{
-			Value: value,
+			Value: line[start:end],
 			Start: start,
-			End:   start + uint32(len(value)),
+			End:   end,
 		}
 		fallthrough
 	case 3:
-		value := fields[2]
-		start := uint32(strings.Index(line, value))
-
-		if start == 0 {
-			start = uint32(len(line))
-		}
+		field := fields[2]
+		start := uint32(field[0])
+		end := uint32(field[1])
 
 		filesystemType = &Field{
-			Value: value,
+			Value: line[start:end],
 			Start: start,
-			End:   start + uint32(len(value)),
+			End:   end,
 		}
 		fallthrough
 	case 2:
-		value := fields[1]
-		start := uint32(strings.Index(line, value))
-
-		if start == 0 {
-			start = uint32(len(line))
-		}
+		field := fields[1]
+		start := uint32(field[0])
+		end := uint32(field[1])
 
 		mountPoint = &Field{
-			Value: value,
+			Value: line[start:end],
 			Start: start,
-			End:   start + uint32(len(value)),
+			End:   end,
 		}
 		fallthrough
 	case 1:
-		value := fields[0]
-		start := uint32(strings.Index(line, value))
+		field := fields[0]
+		start := uint32(field[0])
+		end := uint32(field[1])
 
 		spec = &Field{
-			Value: value,
+			Value: line[start:end],
 			Start: start,
-			End:   start + uint32(len(value)),
+			End:   end,
 		}
 	}
 
 	entry := FstabEntry{
-		Line: uint32(lineNumber),
-		Fields: FstabFields{
-			Spec:           spec,
-			MountPoint:     mountPoint,
-			FilesystemType: filesystemType,
-			Options:        options,
-			Freq:           freq,
-			Pass:           pass,
+		Type: FstabEntryTypeLine,
+		Line: FstabLine{
+			Line: uint32(lineNumber),
+			Fields: FstabFields{
+				Spec:           spec,
+				MountPoint:     mountPoint,
+				FilesystemType: filesystemType,
+				Options:        options,
+				Freq:           freq,
+				Pass:           pass,
+			},
 		},
 	}
 	p.entries = append(p.entries, entry)
@@ -305,6 +308,16 @@ func (p *FstabParser) AddLine(line string, lineNumber int) error {
 	return nil
 }
 
+func (p *FstabParser) AddCommentLine(line string, lineNumber int) {
+	entry := FstabLine{
+		Line: uint32(lineNumber),
+	}
+	p.entries = append(p.entries, FstabEntry{
+		Type: FstabEntryTypeComment,
+		Line: entry,
+	})
+}
+
 func (p *FstabParser) ParseFromContent(content string) []common.ParseError {
 	errors := []common.ParseError{}
 	lines := strings.Split(content, "\n")
@@ -314,6 +327,11 @@ func (p *FstabParser) ParseFromContent(content string) []common.ParseError {
 			continue
 		}
 
+		if commentPattern.MatchString(line) {
+			p.AddCommentLine(line, index)
+			continue
+		}
+
 		err := p.AddLine(line, index)
 
 		if err != nil {
@@ -329,11 +347,11 @@ func (p *FstabParser) ParseFromContent(content string) []common.ParseError {
 
 func (p *FstabParser) GetEntry(line uint32) (*FstabEntry, bool) {
 	index, found := slices.BinarySearchFunc(p.entries, line, func(entry FstabEntry, line uint32) int {
-		if entry.Line < line {
+		if entry.Line.Line < line {
 			return -1
 		}
 
-		if entry.Line > line {
+		if entry.Line.Line > line {
 			return 1
 		}
 
@@ -355,10 +373,15 @@ func (p *FstabParser) AnalyzeValues() []protocol.Diagnostic {
 	diagnostics := []protocol.Diagnostic{}
 
 	for _, entry := range p.entries {
-		newDiagnostics := entry.CheckIsValid()
+		switch entry.Type {
+		case FstabEntryTypeLine:
+			newDiagnostics := entry.Line.CheckIsValid()
 
-		if len(newDiagnostics) > 0 {
-			diagnostics = append(diagnostics, newDiagnostics...)
+			if len(newDiagnostics) > 0 {
+				diagnostics = append(diagnostics, newDiagnostics...)
+			}
+		case FstabEntryTypeComment:
+			// Do nothing
 		}
 	}
 

handlers/fstab/text-document-completion.go

@@ -22,32 +22,33 @@ func TextDocumentCompletion(context *glsp.Context, params *protocol.CompletionPa
 	}
 
 	cursor := params.Position.Character
-	targetField := entry.GetFieldAtPosition(cursor)
+	line := entry.Line
+	targetField := line.GetFieldAtPosition(cursor)
 
 	switch targetField {
 	case FstabFieldSpec:
-		value, cursor := GetFieldSafely(entry.Fields.Spec, cursor)
+		value, cursor := GetFieldSafely(line.Fields.Spec, cursor)
 
 		return fstabdocumentation.SpecField.FetchCompletions(
 			value,
 			cursor,
 		), nil
 	case FstabFieldMountPoint:
-		value, cursor := GetFieldSafely(entry.Fields.MountPoint, cursor)
+		value, cursor := GetFieldSafely(line.Fields.MountPoint, cursor)
 
 		return fstabdocumentation.MountPointField.FetchCompletions(
 			value,
 			cursor,
 		), nil
 	case FstabFieldFileSystemType:
-		value, cursor := GetFieldSafely(entry.Fields.FilesystemType, cursor)
+		value, cursor := GetFieldSafely(line.Fields.FilesystemType, cursor)
 
 		return fstabdocumentation.FileSystemTypeField.FetchCompletions(
 			value,
 			cursor,
 		), nil
 	case FstabFieldOptions:
-		fileSystemType := entry.Fields.FilesystemType.Value
+		fileSystemType := line.Fields.FilesystemType.Value
 
 		var optionsField docvalues.Value
 
@@ -57,7 +58,7 @@ func TextDocumentCompletion(context *glsp.Context, params *protocol.CompletionPa
 			optionsField = fstabdocumentation.DefaultMountOptionsField
 		}
 
-		value, cursor := GetFieldSafely(entry.Fields.Options, cursor)
+		value, cursor := GetFieldSafely(line.Fields.Options, cursor)
 
 		completions := optionsField.FetchCompletions(
 			value,
@@ -66,14 +67,14 @@ func TextDocumentCompletion(context *glsp.Context, params *protocol.CompletionPa
 
 		return completions, nil
 	case FstabFieldFreq:
-		value, cursor := GetFieldSafely(entry.Fields.Freq, cursor)
+		value, cursor := GetFieldSafely(line.Fields.Freq, cursor)
 
 		return fstabdocumentation.FreqField.FetchCompletions(
 			value,
 			cursor,
 		), nil
 	case FstabFieldPass:
-		value, cursor := GetFieldSafely(entry.Fields.Pass, cursor)
+		value, cursor := GetFieldSafely(line.Fields.Pass, cursor)
 
 		return fstabdocumentation.PassField.FetchCompletions(
 			value,

handlers/fstab/text-document-hover.go

@@ -0,0 +1,67 @@
+package fstab
+
+import (
+	docvalues "config-lsp/doc-values"
+	fstabdocumentation "config-lsp/handlers/fstab/documentation"
+	"strings"
+
+	"github.com/tliron/glsp"
+	protocol "github.com/tliron/glsp/protocol_3_16"
+)
+
+func TextDocumentHover(context *glsp.Context, params *protocol.HoverParams) (*protocol.Hover, error) {
+	cursor := params.Position.Character
+
+	parser := documentParserMap[params.TextDocument.URI]
+
+	entry, found := parser.GetEntry(params.Position.Line)
+
+	// Empty line
+	if !found {
+		return nil, nil
+	}
+
+	// Comment line
+	if entry.Type == FstabEntryTypeComment {
+		return nil, nil
+	}
+
+	line := entry.Line
+	targetField := line.GetFieldAtPosition(cursor)
+
+	switch targetField {
+	case FstabFieldSpec:
+		return &SpecHoverField, nil
+	case FstabFieldMountPoint:
+		return &MountPointHoverField, nil
+	case FstabFieldFileSystemType:
+		return &FileSystemTypeField, nil
+	case FstabFieldOptions:
+		fileSystemType := line.Fields.FilesystemType.Value
+		var optionsField docvalues.Value
+
+		if foundField, found := fstabdocumentation.MountOptionsMapField[fileSystemType]; found {
+			optionsField = foundField
+		} else {
+			optionsField = fstabdocumentation.DefaultMountOptionsField
+		}
+
+		relativeCursor := cursor - line.Fields.Options.Start
+		fieldInfo := optionsField.FetchHoverInfo(line.Fields.Options.Value, relativeCursor)
+
+		hover := protocol.Hover{
+			Contents: protocol.MarkupContent{
+				Kind:  protocol.MarkupKindMarkdown,
+				Value: strings.Join(fieldInfo, "\n"),
+			},
+		}
+
+		return &hover, nil
+	case FstabFieldFreq:
+		return &FreqHoverField, nil
+	case FstabFieldPass:
+		return &PassHoverField, nil
+	}
+
+	return nil, nil
+}

root-handler/handler.go

@@ -24,6 +24,7 @@ func SetUpRootHandler() {
 		TextDocumentDidOpen:    TextDocumentDidOpen,
 		TextDocumentDidChange:  TextDocumentDidChange,
 		TextDocumentCompletion: TextDocumentCompletion,
+		TextDocumentHover:      TextDocumentHover,
 	}
 
 	server := server.NewServer(&lspHandler, lsName, false)

root-handler/text-document-hover.go

@@ -0,0 +1,21 @@
+package roothandler
+
+import (
+	"config-lsp/handlers/fstab"
+
+	"github.com/tliron/glsp"
+	protocol "github.com/tliron/glsp/protocol_3_16"
+)
+
+func TextDocumentHover(context *glsp.Context, params *protocol.HoverParams) (*protocol.Hover, error) {
+	language := rootHandler.GetLanguageForDocument(params.TextDocument.URI)
+
+	switch language {
+	case LanguageFstab:
+		return fstab.TextDocumentHover(context, params)
+	case LanguageSSHDConfig:
+		return nil, nil
+	}
+
+	panic("root-handler/TextDocumentHover: unexpected language" + language)
+}

utils/common.go

@@ -136,6 +136,16 @@ func FindPreviousCharacter(line string, character string, startIndex int) (int,
 	return 0, false
 }
 
+func FindNextCharacter(line string, character string, startIndex int) (int, bool) {
+	for index := startIndex; index < len(line); index++ {
+		if string(line[index]) == character {
+			return index, true
+		}
+	}
+
+	return 0, false
+}
+
 func MergeMaps[T comparable, O any](maps ...map[T]O) map[T]O {
 	result := make(map[T]O)
 

utils/strings.go

@@ -0,0 +1,7 @@
+package utils
+
+import "strings"
+
+func IndexOffset(s string, search string, start int) int {
+	return strings.Index(s[start:], search) + start
+}