mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-11-28 14:42:46 +00:00
82 lines
1.8 KiB
Go
82 lines
1.8 KiB
Go
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package util
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import (
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"bytes"
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"context"
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"github.com/tetratelabs/wazero/api"
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)
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// NOTE:
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// the below functions are not very well optimized
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// for repeated calls. this is relying on the fact
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// that the only place they get used (tempnam), is
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// not called very often, should only be once per run
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// so calls to ExportedFunction() and Call() instead
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// of caching api.Function and using CallWithStack()
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// will work out the same (if only called once).
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// maxaddr is the maximum
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// wasm32 memory address.
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const maxaddr = ^uint32(0)
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func malloc(ctx context.Context, mod api.Module, sz uint32) uint32 {
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stack, err := mod.ExportedFunction("malloc").Call(ctx, uint64(sz))
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if err != nil {
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panic(err)
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}
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ptr := api.DecodeU32(stack[0])
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if ptr == 0 {
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panic("out of memory")
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}
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return ptr
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}
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func free(ctx context.Context, mod api.Module, ptr uint32) {
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if ptr != 0 {
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mod.ExportedFunction("free").Call(ctx, uint64(ptr))
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}
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}
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func view(ctx context.Context, mod api.Module, ptr uint32, n uint32) []byte {
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if n == 0 {
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n = maxaddr - ptr
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}
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mem := mod.Memory()
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b, ok := mem.Read(ptr, n)
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if !ok {
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panic("out of range")
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}
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return b
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}
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func read(ctx context.Context, mod api.Module, ptr, n uint32) []byte {
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return bytes.Clone(view(ctx, mod, ptr, n))
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}
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func readString(ctx context.Context, mod api.Module, ptr, n uint32) string {
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return string(view(ctx, mod, ptr, n))
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}
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func write(ctx context.Context, mod api.Module, b []byte) uint32 {
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mem := mod.Memory()
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len := uint32(len(b))
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ptr := malloc(ctx, mod, len)
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ok := mem.Write(ptr, b)
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if !ok {
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panic("out of range")
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}
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return ptr
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}
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func writeString(ctx context.Context, mod api.Module, str string) uint32 {
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mem := mod.Memory()
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len := uint32(len(str) + 1)
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ptr := malloc(ctx, mod, len)
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ok := mem.WriteString(ptr, str)
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if !ok {
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panic("out of range")
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}
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return ptr
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}
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