152 lines
3.6 KiB
Go
152 lines
3.6 KiB
Go
// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// builtin-os-file.go
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package expr
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import (
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"fmt"
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"io"
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"slices"
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"git.portale-stac.it/go-pkg/expr/kern"
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)
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const paramHandleOrPath = "handle-or-path"
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const fileReadTextIteratorType = "fileReadTextIterator"
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type fileReadTextIterator struct {
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osReader *osReader
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index int
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count int
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line string
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autoClose bool
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}
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func newReadTextIterator(r *osReader, autoClose bool) *fileReadTextIterator {
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return &fileReadTextIterator{osReader: r, index: -1, autoClose: autoClose}
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}
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func (it *fileReadTextIterator) TypeName() string {
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return fileReadTextIteratorType
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}
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func (it *fileReadTextIterator) String() string {
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if it.osReader != nil && it.osReader.fh != nil {
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return fmt.Sprintf("$(%s@%q)", fileReadTextIteratorType, it.osReader.fh.Name())
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}
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return fmt.Sprintf("$(%s@<nil>)", fileReadTextIteratorType)
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}
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func (it *fileReadTextIterator) Count() int {
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return it.count
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}
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func (it *fileReadTextIterator) Next() (item any, err error) { // must return io.EOF after the last item
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if it.osReader.fh != nil {
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if it.line, err = it.osReader.reader.ReadString('\n'); err == nil {
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it.index++
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it.count++
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item = it.line[0 : len(it.line)-1]
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} else if it.autoClose {
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it.Clean()
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}
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}
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return
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}
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func (it *fileReadTextIterator) Current() (item any, err error) {
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if len(it.line) > 0 {
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item = it.line[0 : len(it.line)-1]
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}
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return
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}
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func (it *fileReadTextIterator) Index() int {
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return it.index
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}
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func (it *fileReadTextIterator) Reset() (err error) {
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if _, err = it.osReader.fh.Seek(0, io.SeekStart); err == nil {
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it.index = -1
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it.count = 0
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it.line = ""
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}
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return
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}
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func (it *fileReadTextIterator) HasOperation(name string) bool {
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return slices.Contains([]string{kern.NextName, kern.ResetName, kern.IndexName, kern.CountName, kern.CurrentName, kern.CleanName}, name)
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}
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func (it *fileReadTextIterator) Clean() (err error) {
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if it.osReader.fh != nil {
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if err = it.osReader.fh.Close(); err == nil {
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it.osReader = nil
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}
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}
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return nil
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}
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func (it *fileReadTextIterator) CallOperation(name string, args map[string]any) (v any, err error) {
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switch name {
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case kern.NextName:
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v, err = it.Next()
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case kern.ResetName:
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err = it.Reset()
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case kern.CleanName:
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err = it.Clean()
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case kern.IndexName:
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v = int64(it.Index())
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case kern.CurrentName:
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v, err = it.Current()
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case kern.CountName:
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v = it.count
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default:
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err = kern.ErrNoOperation(name)
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}
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return
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}
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func fileReadIteratorFunc(ctx kern.ExprContext, name string, args map[string]any) (result any, err error) {
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var handle *osReader
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var invalidFileHandle any
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var ok, autoClose bool
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result = nil
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if handle, ok = args[paramHandleOrPath].(*osReader); !ok {
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if fileName, ok := args[paramHandleOrPath].(string); ok && len(fileName) > 0 {
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var handleAny any
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if handleAny, err = openFileFunc(ctx, name, map[string]any{kern.ParamFilepath: fileName}); err != nil {
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return
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}
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if handleAny != nil {
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handle = handleAny.(*osReader)
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autoClose = true
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}
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} else {
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invalidFileHandle = args[paramHandleOrPath]
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}
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}
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if handle != nil {
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result = newReadTextIterator(handle, autoClose)
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}
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if err == nil && (handle == nil || invalidFileHandle != nil) {
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err = errInvalidFileHandle(name, invalidFileHandle)
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}
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return
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}
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// func ImportOsIterFuncs(ctx ExprContext) {
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// ctx.RegisterFunc("fileReadIterator", NewGolangFunctor(fileReadIteratorFunc), TypeIterator, []ExprFuncParam{
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// NewFuncParam(paramHandleOrPath),
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// })
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// }
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// func init() {
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// RegisterBuiltinModule("os.file", ImportOsIterFuncs, "Operating system file iterator functions")
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// }
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