Define immutable configuration searches
This commit is contained in:
266
internal/engine/discovery.go
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266
internal/engine/discovery.go
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@@ -0,0 +1,266 @@
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package engine
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import (
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"path/filepath"
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"runtime"
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"strings"
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)
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// Search is an immutable ordered description of possible host-file inputs.
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// It does not access the filesystem until a later loading integration consumes it.
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type Search struct {
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entries []searchEntry
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issues []string
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}
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// FilenameGroup is an immutable ordered group used by a directory search.
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type FilenameGroup struct {
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kind filenameGroupKind
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names []string
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issues []string
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}
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// DirectorySearchOptions controls the filename groups used by SearchDirectory.
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// A nil Filenames slice selects the default groups; a non-nil empty slice selects none.
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type DirectorySearchOptions struct {
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Filenames []FilenameGroup
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}
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// SearchOptions controls whether a later source consumption requires a match.
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type SearchOptions struct {
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Required bool
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}
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type filenameGroupKind uint8
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const (
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filenameGroupEmpty filenameGroupKind = iota
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filenameGroupNamed
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filenameGroupGeneric
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filenameGroupCustom
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)
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type searchEntryKind uint8
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const (
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searchEntryPath searchEntryKind = iota + 1
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searchEntryDirectory
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)
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type directoryBaseKind uint8
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const (
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directoryBaseLiteral directoryBaseKind = iota
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directoryBaseUnixLocal
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directoryBaseUnixEtc
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directoryBaseUserConfig
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directoryBaseHome
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directoryBaseWorking
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)
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type searchEntry struct {
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kind searchEntryKind
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path string
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baseKind directoryBaseKind
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directory string
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appendSlug bool
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slugPrefix string
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filenames []FilenameGroup
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}
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// NamedFilenames selects <application>.yml followed by <application>.yaml.
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func NamedFilenames() FilenameGroup {
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return FilenameGroup{kind: filenameGroupNamed}
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}
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// GenericFilenames selects config.yml, config.yaml, main.yml, and main.yaml.
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func GenericFilenames() FilenameGroup {
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return FilenameGroup{kind: filenameGroupGeneric}
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}
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// CustomFilenames selects literal filename components in the supplied order.
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func CustomFilenames(names ...string) FilenameGroup {
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group := FilenameGroup{kind: filenameGroupCustom, names: append([]string(nil), names...)}
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for _, name := range group.names {
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if !validFilenameComponent(name) {
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group.issues = append(group.issues, "custom filename must be a usable host filename component")
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}
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}
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return group
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}
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// SearchDirectory searches the supplied directory using the selected filename groups.
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// With omitted options or nil Filenames, it selects Named then Generic filenames.
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func SearchDirectory(directory string, supplied ...DirectorySearchOptions) Search {
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search := Search{}
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if len(supplied) > 1 {
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search.issues = append(search.issues, "directory search accepts at most one options value")
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}
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var groups []FilenameGroup
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if len(supplied) == 0 || supplied[0].Filenames == nil {
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groups = []FilenameGroup{NamedFilenames(), GenericFilenames()}
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} else {
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groups = cloneFilenameGroups(supplied[0].Filenames)
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}
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search.entries = append(search.entries, searchEntry{
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kind: searchEntryDirectory, baseKind: directoryBaseLiteral,
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directory: directory, filenames: groups,
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})
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return search
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}
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// Paths describes literal host-file candidates in the supplied order.
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func Paths(paths ...string) Search {
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search := Search{entries: make([]searchEntry, 0, len(paths))}
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for _, path := range append([]string(nil), paths...) {
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search.entries = append(search.entries, searchEntry{kind: searchEntryPath, path: path})
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}
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return search
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}
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// Searches concatenates descriptions in order and snapshots their entries.
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func Searches(searches ...Search) Search {
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result := Search{}
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for _, search := range append([]Search(nil), searches...) {
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result.entries = append(result.entries, cloneSearchEntries(search.entries)...)
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result.issues = append(result.issues, search.issues...)
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}
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return result
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}
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// UnixSystemDirectories describes the conventional Unix system directories.
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func UnixSystemDirectories() Search {
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namedGeneric := []FilenameGroup{NamedFilenames(), GenericFilenames()}
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return Search{entries: []searchEntry{
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{kind: searchEntryDirectory, baseKind: directoryBaseUnixLocal, appendSlug: true, filenames: cloneFilenameGroups(namedGeneric)},
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{kind: searchEntryDirectory, baseKind: directoryBaseUnixEtc, appendSlug: true, filenames: cloneFilenameGroups(namedGeneric)},
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{kind: searchEntryDirectory, baseKind: directoryBaseUnixEtc, filenames: []FilenameGroup{NamedFilenames()}},
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}}
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}
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// UserConfigDirectory describes the Go user-configuration directory searches.
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func UserConfigDirectory() Search {
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return Search{entries: []searchEntry{
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{kind: searchEntryDirectory, baseKind: directoryBaseUserConfig, appendSlug: true, filenames: defaultFilenameGroups()},
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{kind: searchEntryDirectory, baseKind: directoryBaseUserConfig, filenames: []FilenameGroup{NamedFilenames()}},
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}}
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}
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// HomeDirectory describes the Go home-directory searches.
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func HomeDirectory() Search {
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return Search{entries: []searchEntry{
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{kind: searchEntryDirectory, baseKind: directoryBaseHome, appendSlug: true, slugPrefix: ".", filenames: defaultFilenameGroups()},
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{kind: searchEntryDirectory, baseKind: directoryBaseHome, filenames: []FilenameGroup{NamedFilenames()}},
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}}
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}
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// WorkingDirectory describes application-named files in the current directory.
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func WorkingDirectory() Search {
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return Search{entries: []searchEntry{{
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kind: searchEntryDirectory, baseKind: directoryBaseWorking,
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filenames: []FilenameGroup{NamedFilenames()},
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}}}
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}
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func defaultFilenameGroups() []FilenameGroup {
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return []FilenameGroup{NamedFilenames(), GenericFilenames()}
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}
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func cloneFilenameGroups(groups []FilenameGroup) []FilenameGroup {
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if groups == nil {
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return nil
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}
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cloned := make([]FilenameGroup, len(groups))
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for i, group := range groups {
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cloned[i] = FilenameGroup{
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kind: group.kind, names: append([]string(nil), group.names...),
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issues: append([]string(nil), group.issues...),
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}
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}
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return cloned
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}
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func cloneSearchEntries(entries []searchEntry) []searchEntry {
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if entries == nil {
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return nil
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}
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cloned := make([]searchEntry, len(entries))
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for i, entry := range entries {
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cloned[i] = entry
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cloned[i].filenames = cloneFilenameGroups(entry.filenames)
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}
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return cloned
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}
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func validateSearch(search Search, application string) []Diagnostic {
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var diagnostics []Diagnostic
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for _, issue := range search.issues {
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diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, issue))
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}
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slugNeeded := false
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for _, entry := range search.entries {
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switch entry.kind {
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case searchEntryPath:
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if entry.path == "" {
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diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "search path must not be empty"))
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}
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case searchEntryDirectory:
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if entry.baseKind == directoryBaseLiteral && entry.directory == "" {
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diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "directory search path must not be empty"))
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}
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if entry.appendSlug {
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slugNeeded = true
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}
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for _, group := range entry.filenames {
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switch group.kind {
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case filenameGroupEmpty, filenameGroupGeneric:
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case filenameGroupNamed:
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slugNeeded = true
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case filenameGroupCustom:
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default:
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diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "filename group is invalid"))
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}
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for _, issue := range group.issues {
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diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, issue))
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}
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}
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default:
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diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "search description is invalid"))
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}
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}
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if slugNeeded && !validFilenameComponent(application) {
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diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "application name must be a usable host filename component"))
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}
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return canonicalDiagnostics(diagnostics)
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}
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func validFilenameComponent(value string) bool {
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if value == "" || value == "." || value == ".." || strings.IndexByte(value, 0) >= 0 {
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return false
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}
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if filepath.IsAbs(value) || filepath.VolumeName(value) != "" || filepath.Base(value) != value {
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return false
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}
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if runtime.GOOS == "windows" {
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return validWindowsFilenameComponent(value)
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}
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return true
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}
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func validWindowsFilenameComponent(value string) bool {
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if strings.ContainsAny(value, `<>:"|?*`) || strings.HasSuffix(value, ".") || strings.HasSuffix(value, " ") {
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return false
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}
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for _, character := range value {
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if character < 32 {
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return false
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}
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}
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base := strings.ToUpper(strings.TrimSuffix(value, filepath.Ext(value)))
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switch base {
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case "CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "COM¹", "COM²", "COM³", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9", "LPT¹", "LPT²", "LPT³":
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return false
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default:
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return true
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}
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}
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