mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-29 10:36:31 +00:00
1e7b32490d
This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).
80 lines
2.5 KiB
Go
80 lines
2.5 KiB
Go
package binary
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"io"
|
|
|
|
"github.com/tetratelabs/wazero/api"
|
|
"github.com/tetratelabs/wazero/internal/leb128"
|
|
"github.com/tetratelabs/wazero/internal/wasm"
|
|
)
|
|
|
|
// dataSegmentPrefix represents three types of data segments.
|
|
//
|
|
// https://www.w3.org/TR/2022/WD-wasm-core-2-20220419/binary/modules.html#data-section
|
|
type dataSegmentPrefix = uint32
|
|
|
|
const (
|
|
// dataSegmentPrefixActive is the prefix for the version 1.0 compatible data segment, which is classified as "active" in 2.0.
|
|
dataSegmentPrefixActive dataSegmentPrefix = 0x0
|
|
// dataSegmentPrefixPassive prefixes the "passive" data segment as in version 2.0 specification.
|
|
dataSegmentPrefixPassive dataSegmentPrefix = 0x1
|
|
// dataSegmentPrefixActiveWithMemoryIndex is the active prefix with memory index encoded which is defined for futur use as of 2.0.
|
|
dataSegmentPrefixActiveWithMemoryIndex dataSegmentPrefix = 0x2
|
|
)
|
|
|
|
func decodeDataSegment(r *bytes.Reader, enabledFeatures api.CoreFeatures, ret *wasm.DataSegment) (err error) {
|
|
dataSegmentPrefx, _, err := leb128.DecodeUint32(r)
|
|
if err != nil {
|
|
err = fmt.Errorf("read data segment prefix: %w", err)
|
|
return
|
|
}
|
|
|
|
if dataSegmentPrefx != dataSegmentPrefixActive {
|
|
if err = enabledFeatures.RequireEnabled(api.CoreFeatureBulkMemoryOperations); err != nil {
|
|
err = fmt.Errorf("non-zero prefix for data segment is invalid as %w", err)
|
|
return
|
|
}
|
|
}
|
|
|
|
switch dataSegmentPrefx {
|
|
case dataSegmentPrefixActive,
|
|
dataSegmentPrefixActiveWithMemoryIndex:
|
|
// Active data segment as in
|
|
// https://www.w3.org/TR/2022/WD-wasm-core-2-20220419/binary/modules.html#data-section
|
|
if dataSegmentPrefx == 0x2 {
|
|
d, _, err := leb128.DecodeUint32(r)
|
|
if err != nil {
|
|
return fmt.Errorf("read memory index: %v", err)
|
|
} else if d != 0 {
|
|
return fmt.Errorf("memory index must be zero but was %d", d)
|
|
}
|
|
}
|
|
|
|
err = decodeConstantExpression(r, enabledFeatures, &ret.OffsetExpression)
|
|
if err != nil {
|
|
return fmt.Errorf("read offset expression: %v", err)
|
|
}
|
|
case dataSegmentPrefixPassive:
|
|
// Passive data segment doesn't need const expr nor memory index encoded.
|
|
// https://www.w3.org/TR/2022/WD-wasm-core-2-20220419/binary/modules.html#data-section
|
|
ret.Passive = true
|
|
default:
|
|
err = fmt.Errorf("invalid data segment prefix: 0x%x", dataSegmentPrefx)
|
|
return
|
|
}
|
|
|
|
vs, _, err := leb128.DecodeUint32(r)
|
|
if err != nil {
|
|
err = fmt.Errorf("get the size of vector: %v", err)
|
|
return
|
|
}
|
|
|
|
ret.Init = make([]byte, vs)
|
|
if _, err = io.ReadFull(r, ret.Init); err != nil {
|
|
err = fmt.Errorf("read bytes for init: %v", err)
|
|
}
|
|
return
|
|
}
|