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84bf87df52
Part of #1055. Added System.Storage.PutEx to compiler. Added StorageFlag in order to denote whether item is constant or not.
61 lines
3.2 KiB
Go
61 lines
3.2 KiB
Go
/*
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Package storage provides functions to access and modify contract's storage.
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Neo storage's model follows simple key-value DB pattern, this storage is a part
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of blockchain state, so you can use it between various invocations of the same
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contract.
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*/
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package storage
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import "github.com/nspcc-dev/neo-go/pkg/interop/iterator"
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// Context represents storage context that is mandatory for Put/Get/Delete
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// operations. It's an opaque type that can only be created properly by
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// GetContext, GetReadOnlyContext or ConvertContextToReadOnly. It's similar
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// to Neo .net framework's StorageContext class.
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type Context struct{}
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// ConvertContextToReadOnly returns new context from the given one, but with
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// writing capability turned off, so that you could only invoke Get and Find
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// using this new Context. If Context is already read-only this function is a
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// no-op. It uses `System.Storage.AsReadOnly` syscall.
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func ConvertContextToReadOnly(ctx Context) Context { return Context{} }
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// GetContext returns current contract's (that invokes this function) storage
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// context. It uses `System.Storage.GetContext` syscall.
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func GetContext() Context { return Context{} }
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// GetReadOnlyContext returns current contract's (that invokes this function)
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// storage context in read-only mode, you can use this context for Get and Find
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// functions, but using it for Put and Delete will fail. It uses
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// `System.Storage.GetReadOnlyContext` syscall.
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func GetReadOnlyContext() Context { return Context{} }
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// Put saves given value with given key in the storage using given Context.
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// Even though it accepts interface{} for both, you can only pass simple types
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// there like string, []byte, int or bool (not structures or slices of more
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// complex types). To put more complex types there serialize them first using
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// runtime.Serialize. This function uses `System.Storage.Put` syscall.
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func Put(ctx Context, key interface{}, value interface{}) {}
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// PutEx is an advanced version of Put which saves given value with given key
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// and given ReadOnly flag in the storage using given Context. `flag` argument
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// can either be odd for constant storage items or even for variable storage items.
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// Refer to Put function description for details on how to pass the remaining
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// arguments. This function uses `System.Storage.PutEx` syscall.
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func PutEx(ctx Context, key interface{}, value interface{}, flag int64) {}
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// Get retrieves value stored for the given key using given Context. See Put
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// documentation on possible key and value types. If the value is not present in
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// the database it returns nil. This function uses `System.Storage.Get` syscall.
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func Get(ctx Context, key interface{}) interface{} { return nil }
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// Delete removes key-value pair from storage by the given key using given
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// Context. See Put documentation on possible key types. This function uses
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// `System.Storage.Delete` syscall.
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func Delete(ctx Context, key interface{}) {}
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// Find returns an iterator.Iterator over key-value pairs in the given Context
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// that match the given key (contain it as a prefix). See Put documentation on
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// possible key types and iterator package documentation on how to use the
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// returned value. This function uses `System.Storage.Find` syscall.
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func Find(ctx Context, key interface{}) iterator.Iterator { return iterator.Iterator{} }
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