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cloudreve/pkg/thumb/pipeline.go

123 lines
2.9 KiB

package thumb
import (
"context"
"errors"
"fmt"
model "github.com/cloudreve/Cloudreve/v3/models"
"github.com/cloudreve/Cloudreve/v3/pkg/util"
"io"
"os"
"path/filepath"
"reflect"
"sort"
"strconv"
)
// Generator generates a thumbnail for a given reader.
type Generator interface {
// Generate generates a thumbnail for a given reader. Src is the original file path, only provided
// for local policy files.
Generate(ctx context.Context, file io.Reader, src string, name string, options map[string]string) (*Result, error)
// Priority of execution order, smaller value means higher priority.
Priority() int
// EnableFlag returns the setting name to enable this generator.
EnableFlag() string
}
type Result struct {
Path string
Continue bool
Cleanup []func()
}
type (
GeneratorType string
GeneratorList []Generator
)
var (
Generators = GeneratorList{}
ErrPassThrough = errors.New("pass through")
ErrNotAvailable = fmt.Errorf("thumbnail not available: %w", ErrPassThrough)
)
func (g GeneratorList) Len() int {
return len(g)
}
func (g GeneratorList) Less(i, j int) bool {
return g[i].Priority() < g[j].Priority()
}
func (g GeneratorList) Swap(i, j int) {
g[i], g[j] = g[j], g[i]
}
// RegisterGenerator registers a thumbnail generator.
func RegisterGenerator(generator Generator) {
Generators = append(Generators, generator)
sort.Sort(Generators)
}
func (p GeneratorList) Generate(ctx context.Context, file io.Reader, src, name string, options map[string]string) (*Result, error) {
inputFile, inputSrc, inputName := file, src, name
for _, generator := range p {
if model.IsTrueVal(options[generator.EnableFlag()]) {
res, err := generator.Generate(ctx, inputFile, inputSrc, inputName, options)
if errors.Is(err, ErrPassThrough) {
util.Log().Debug("Failed to generate thumbnail using %s for %s: %s, passing through to next generator.", reflect.TypeOf(generator).String(), name, err)
continue
}
if res.Continue {
util.Log().Debug("Generator %s for %s returned continue, passing through to next generator.", reflect.TypeOf(generator).String(), name)
// defer cleanup funcs
for _, cleanup := range res.Cleanup {
defer cleanup()
}
// prepare file reader for next generator
intermediate, err := os.Open(res.Path)
if err != nil {
return nil, fmt.Errorf("failed to open intermediate thumb file: %w", err)
}
defer intermediate.Close()
inputFile = intermediate
inputSrc = res.Path
inputName = filepath.Base(res.Path)
continue
}
return res, err
}
}
return nil, ErrNotAvailable
}
func (p GeneratorList) Priority() int {
return 0
}
func (p GeneratorList) EnableFlag() string {
return ""
}
func thumbSize(options map[string]string) (uint, uint) {
w, h := uint(400), uint(300)
if wParsed, err := strconv.Atoi(options["thumb_width"]); err == nil {
w = uint(wParsed)
}
if hParsed, err := strconv.Atoi(options["thumb_height"]); err == nil {
h = uint(hParsed)
}
return w, h
}