mirror of https://github.com/zellyn/diskii.git
73 lines
2.2 KiB
Go
73 lines
2.2 KiB
Go
// Copyright © 2016 Zellyn Hunter <zellyn@gmail.com>
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// ops.go contains the interfaces and helper functions for operating
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// on disk images logically: catalog, rename, delete, create files,
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// etc.
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package disk
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import (
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"errors"
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"fmt"
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"sort"
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"strings"
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)
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// Descriptor describes a file's characteristics.
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type Descriptor struct {
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Name string
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Sectors int
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Length int
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Locked bool
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}
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// Operator is the interface that can operate on disks.
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type Operator interface {
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// Name returns the name of the operator.
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Name() string
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// HasSubdirs returns true if the underlying operating system on the
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// disk allows subdirectories.
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HasSubdirs() bool
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// Catalog returns a catalog of disk entries. subdir should be empty
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// for operating systems that do not support subdirectories.
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Catalog(subdir string) ([]Descriptor, error)
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}
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// operatorFactory is the type of functions that accept a SectorDisk,
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// and may return an Operator interface to operate on it.
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type operatorFactory func(SectorDisk) (Operator, error)
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// operatorFactories is the map of currently-registered operator
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// factories.
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var operatorFactories map[string]operatorFactory
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func init() {
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operatorFactories = make(map[string]operatorFactory)
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}
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// RegisterOperatorFactory registers an operator factory with the
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// given name: a function that accepts a SectorDisk, and may return an
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// Operator. It doesn't lock operatorFactories: it is expected to be
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// called only from package `init` functions.
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func RegisterOperatorFactory(name string, factory operatorFactory) {
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operatorFactories[name] = factory
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}
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// OperatorFor returns an Operator for the given SectorDisk, if possible.
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func OperatorFor(sd SectorDisk) (Operator, error) {
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if len(operatorFactories) == 0 {
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return nil, errors.New("Cannot find an operator matching the given disk image (none registered)")
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}
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for _, factory := range operatorFactories {
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if operator, err := factory(sd); err == nil {
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return operator, nil
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}
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}
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names := make([]string, 0, len(operatorFactories))
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for name := range operatorFactories {
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names = append(names, `"`+name+`"`)
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}
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sort.Strings(names)
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return nil, fmt.Errorf("Cannot find an operator matching the given disk image (tried %s)", strings.Join(names, ", "))
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}
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