Crate soroban_env_guest

This crate provides the [Guest] type, the “stub” implementation of the Env interface used for communicating between a contract guest and its host. It is only defined for cfg(target_family = "wasm").

It also re-exports all of the content of the soroban_env_common crate for use by guest code. Most of the type and module definitions visible here are actually defined in the common crate.

Modules

meta

This module contains version constants (and other metadata) that are embedded in binaries (especially WASM binaries) compiled against a particular version of this crate. Versioning at this level provides an early diagnostic check for compatibility between a loaded WASM binary and the Env interface provided by the host, rather than a cryptic failure due to a runtime host function signature mismatch.

num

xdr

Structs

AddressObject

Bool

BytesObject

ConversionError

Error type indicating a failure to convert some type to another; details of the failed conversion may be written to the debug log, when possible.

DurationObject

DurationSmall

DurationVal

Error

Wrapper for a Val that is tagged with [Tag::Error], interpreting the Val’s body as a pair of a 28-bit error-type code and a 32-bit error code. The error-type codes correspond to the enumerated cases of ScErrorType, and the error codes correspond to the code values stored in each variant of the ScError union.

I32Val

I64Object

I64Small

I64Val

I256

A 256-bit signed integer type.

I128Object

I128Small

I128Val

I256Object

I256Small

I256Val

MapObject

Object

Wrapper for a Val that is tagged with one of the object types, interpreting the Val’s body as containing a 32-bit handle to a host object.

ScValObjRef

ScValObject

ScValObject (and its reference-based type ScValObjRef) is a small wrapper type that does not have its own XDR definition, it just denotes (as a type) the subset of ScVal values that need to be represented in Val by one of the cases that can be an Object. In other words Val::try_from_val(&v, e).is_object() will be true iff ScValObject::classify(v) is Ok(ScValObject(v)).

StringObject

Symbol

SymbolObject

SymbolSmall

SymbolSmallIter

An iterator that decodes the individual bit-packed characters from a symbol and yields them as regular Rust char values.

SymbolStr

An expanded form of a Symbol that stores its characters as ASCII-range bytes in a u8 array – up to the maximum size of a large symbol object – rather than as packed 6-bit codes within a u64. Useful for interoperation with standard Rust string types.

TimepointObject

TimepointSmall

TimepointVal

U32Val

U64Object

U64Small

U64Val

U256

A 256-bit unsigned integer type.

U128Object

U128Small

U128Val

U256Object

U256Small

U256Val

Val

VecObject

Version

VmCaller

Void

Enums

StorageType

This is just a distinct enum local to the env interface that is used as an argument to storage functions. It doesn’t correspond to any [Val] types, and is passed by direct marshalling as a u64.

SymbolError

Errors related to operations on the SymbolObject and SymbolSmall types.

Tag

Code values for the 8 tag bits in the bit-packed representation of Val. These don’t coincide with tag numbers in the SCVal XDR but cover all those cases as well as some optimized refinements for special cases (boolean true and false, small-value forms).

Constants

VERSION

Traits

CheckedEnvArg

This trait is used by macro-generated dispatch and forwarding functions to check arguments being passed to the Env. The default implementations call through to the Env integrity-checking functions.

Compare

General trait representing the ability to compare two values of some type. Similar to core::cmp::Cmp but with two key differences: the comparison is fallible, and is provided by some external type implementing Compare rather than the compared type itself.

Convert

General trait representing a the ability of some object to perform a (possibly unsuccessful) conversion between two other types.

Env

This trait represents the interface between Host and Guest, used by client contract code and implemented (via Env) by the host. It consists of functions that take or return only 64-bit values such as Val or u64.

EnvBase

Base trait extended by the Env trait, providing various special-case functions that do not simply call across cross the guest/host interface.

TryFromVal

Trait for types that can be fallibly converted to another type V, analogous to the standard Rust type TryFrom, but making use of the provided Env implementation E in order to convert parts of the type that require it. Mainly this exists because Val types that contain object handles need to delegate to the environment to look up and extract the content of those handles.

TryIntoVal

The opposite trait to TryFromVal, analogous to the way that TryInto exists as an opposite to TryFrom. Exists only for convenience of doing conversions via .try_into_val(e) or specifying convertability with a bound like TryIntoVal<E,Other>.

VmCallerEnv

This trait is a variant of the Env trait used to define the interface implemented by Host. The wasmi VM dispatch functions (in soroban_env_host::dispatch) call methods on VmCallerEnv, passing a VmCaller that wraps the wasmi Caller context, and then convert any Result::Err(...) return value into a VM trap, halting VM execution.