gapid/memory/resource.go

// Copyright (C) 2016 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package memory

import (
	"bytes"
	"fmt"
	"io"

	"android.googlesource.com/platform/tools/gpu/framework/binary"
	"android.googlesource.com/platform/tools/gpu/framework/binary/endian"
	"android.googlesource.com/platform/tools/gpu/framework/device"
	"android.googlesource.com/platform/tools/gpu/framework/id"
	"android.googlesource.com/platform/tools/gpu/framework/log"
	"android.googlesource.com/platform/tools/gpu/gapid/database"
)

// Resource returns a Slice that wraps a resource stored in the database.
// resId is the identifier of the data and size is the size in bytes of the
// data.
func Resource(resId id.ID, size uint64) Slice {
	return resource{resId, size}
}

type resource struct {
	resId id.ID
	size  uint64
}

func (r resource) Get(ctx log.Context, d database.Database, offset uint64, out []byte) error {
	data, err := r.getData(ctx, d)
	if err != nil {
		return err
	}
	copy(out, data[offset:])
	return nil
}

func (r resource) getData(ctx log.Context, d database.Database) ([]byte, error) {
	res, err := database.Resolve(ctx, r.resId, d)
	if err != nil {
		return nil, err
	}
	data := res.([]byte)
	if r.size != uint64(len(data)) {
		return nil, fmt.Errorf("Loaded resource is unexpected size. Expected 0x%x, got 0x%x for resource %v",
			r.size, len(data), r.resId)
	}
	return data, nil
}

func (r resource) ResourceID(ctx log.Context, d database.Database) (id.ID, error) {
	return r.resId, nil
}

func (r resource) Size() uint64 {
	return r.size
}

func (r resource) Slice(rng Range) Slice {
	return newResourceSlice(r, rng)
}

func (r resource) ValidRanges() RangeList {
	return RangeList{Range{Size: r.Size()}}
}

func (r resource) String() string {
	return fmt.Sprintf("Resource[%v]", r.resId)
}

func (r resource) NewReader(ctx log.Context, d database.Database) io.Reader {
	data, err := r.getData(ctx, d)
	if err != nil {
		return failedReader{err}
	}
	return bytes.NewReader(data)
}

func newResourceSlice(src resource, rng Range) Slice {
	if uint64(rng.Last()) > src.Size() {
		panic(fmt.Errorf("Slice range %v out of bounds %v", rng, Range{Base: 0, Size: src.Size()}))
	}
	return resourceSlice{src, rng}
}

type resourceSlice struct {
	src resource
	rng Range
}

func (s resourceSlice) Get(ctx log.Context, d database.Database, offset uint64, out []byte) error {
	trim := min(s.rng.Size-offset, uint64(len(out)))
	return s.src.Get(ctx, d, s.rng.First()+offset, out[:trim])
}

func (r resourceSlice) NewReader(ctx log.Context, d database.Database) io.Reader {
	data, err := r.src.getData(ctx, d)
	if err != nil {
		return failedReader{err}
	}
	return bytes.NewReader(data[r.rng.First() : r.rng.Last()+1])
}

func (s resourceSlice) ResourceID(ctx log.Context, d database.Database) (id.ID, error) {
	subslice := subslice{
		source: s.src.resId,
		from:   s.rng.Base,
		size:   s.rng.Size,
	}
	return database.Store(ctx, &subslice, d)
}

func (s resourceSlice) Size() uint64 {
	return s.rng.Size
}

func (s resourceSlice) Slice(rng Range) Slice {
	return newResourceSlice(s.src, Range{Base: s.rng.Base + rng.Base, Size: rng.Size})
}

func (s resourceSlice) ValidRanges() RangeList {
	return RangeList{Range{Size: s.rng.Size}}
}

func (s resourceSlice) String() string {
	return fmt.Sprintf("%v[%v]", s.src, s.rng)
}

// subslice is a lazy builder that retrieves a subslice of another byte slice.
type subslice struct {
	binary.Generate `java:"disable"`
	source          id.ID
	from            uint64
	size            uint64
}

func (s *subslice) WriteForHash(w io.Writer) error {
	u := endian.Writer(w, device.LittleEndian)
	u.Uint64(s.from)
	u.Uint64(s.size)
	u.Data(s.source[:20])
	return u.Error()
}

func (s *subslice) BuildLazy(ctx log.Context, c interface{}, d database.Database) (interface{}, error) {
	res, err := database.Resolve(ctx, s.source, d)
	if err != nil {
		return nil, err
	}
	data := res.([]byte)
	return data[s.from : s.from+s.size], nil
}

type failedReader struct {
	err error
}

func (fr failedReader) Read([]byte) (int, error) {
	return 0, fr.err
}