github.com/tetratelabs/wazero@v1.2.1/api/wasm.go (about)

     1  // Package api includes constants and interfaces used by both end-users and internal implementations.
     2  package api
     3  
     4  import (
     5  	"context"
     6  	"fmt"
     7  	"math"
     8  
     9  	"github.com/tetratelabs/wazero/internal/internalapi"
    10  )
    11  
    12  // ExternType classifies imports and exports with their respective types.
    13  //
    14  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#external-types%E2%91%A0
    15  type ExternType = byte
    16  
    17  const (
    18  	ExternTypeFunc   ExternType = 0x00
    19  	ExternTypeTable  ExternType = 0x01
    20  	ExternTypeMemory ExternType = 0x02
    21  	ExternTypeGlobal ExternType = 0x03
    22  )
    23  
    24  // The below are exported to consolidate parsing behavior for external types.
    25  const (
    26  	// ExternTypeFuncName is the name of the WebAssembly 1.0 (20191205) Text Format field for ExternTypeFunc.
    27  	ExternTypeFuncName = "func"
    28  	// ExternTypeTableName is the name of the WebAssembly 1.0 (20191205) Text Format field for ExternTypeTable.
    29  	ExternTypeTableName = "table"
    30  	// ExternTypeMemoryName is the name of the WebAssembly 1.0 (20191205) Text Format field for ExternTypeMemory.
    31  	ExternTypeMemoryName = "memory"
    32  	// ExternTypeGlobalName is the name of the WebAssembly 1.0 (20191205) Text Format field for ExternTypeGlobal.
    33  	ExternTypeGlobalName = "global"
    34  )
    35  
    36  // ExternTypeName returns the name of the WebAssembly 1.0 (20191205) Text Format field of the given type.
    37  //
    38  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#exports%E2%91%A4
    39  func ExternTypeName(et ExternType) string {
    40  	switch et {
    41  	case ExternTypeFunc:
    42  		return ExternTypeFuncName
    43  	case ExternTypeTable:
    44  		return ExternTypeTableName
    45  	case ExternTypeMemory:
    46  		return ExternTypeMemoryName
    47  	case ExternTypeGlobal:
    48  		return ExternTypeGlobalName
    49  	}
    50  	return fmt.Sprintf("%#x", et)
    51  }
    52  
    53  // ValueType describes a parameter or result type mapped to a WebAssembly
    54  // function signature.
    55  //
    56  // The following describes how to convert between Wasm and Golang types:
    57  //
    58  //   - ValueTypeI32 - EncodeU32 DecodeU32 for uint32 / EncodeI32 DecodeI32 for int32
    59  //   - ValueTypeI64 - uint64(int64)
    60  //   - ValueTypeF32 - EncodeF32 DecodeF32 from float32
    61  //   - ValueTypeF64 - EncodeF64 DecodeF64 from float64
    62  //   - ValueTypeExternref - unintptr(unsafe.Pointer(p)) where p is any pointer
    63  //     type in Go (e.g. *string)
    64  //
    65  // e.g. Given a Text Format type use (param i64) (result i64), no conversion is
    66  // necessary.
    67  //
    68  //	results, _ := fn(ctx, input)
    69  //	result := result[0]
    70  //
    71  // e.g. Given a Text Format type use (param f64) (result f64), conversion is
    72  // necessary.
    73  //
    74  //	results, _ := fn(ctx, api.EncodeF64(input))
    75  //	result := api.DecodeF64(result[0])
    76  //
    77  // Note: This is a type alias as it is easier to encode and decode in the
    78  // binary format.
    79  //
    80  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#binary-valtype
    81  type ValueType = byte
    82  
    83  const (
    84  	// ValueTypeI32 is a 32-bit integer.
    85  	ValueTypeI32 ValueType = 0x7f
    86  	// ValueTypeI64 is a 64-bit integer.
    87  	ValueTypeI64 ValueType = 0x7e
    88  	// ValueTypeF32 is a 32-bit floating point number.
    89  	ValueTypeF32 ValueType = 0x7d
    90  	// ValueTypeF64 is a 64-bit floating point number.
    91  	ValueTypeF64 ValueType = 0x7c
    92  
    93  	// ValueTypeExternref is a externref type.
    94  	//
    95  	// Note: in wazero, externref type value are opaque raw 64-bit pointers,
    96  	// and the ValueTypeExternref type in the signature will be translated as
    97  	// uintptr in wazero's API level.
    98  	//
    99  	// For example, given the import function:
   100  	//	(func (import "env" "f") (param externref) (result externref))
   101  	//
   102  	// This can be defined in Go as:
   103  	//  r.NewHostModuleBuilder("env").
   104  	//		NewFunctionBuilder().
   105  	//		WithFunc(func(context.Context, _ uintptr) (_ uintptr) { return }).
   106  	//		Export("f")
   107  	//
   108  	// Note: The usage of this type is toggled with api.CoreFeatureBulkMemoryOperations.
   109  	ValueTypeExternref ValueType = 0x6f
   110  )
   111  
   112  // ValueTypeName returns the type name of the given ValueType as a string.
   113  // These type names match the names used in the WebAssembly text format.
   114  //
   115  // Note: This returns "unknown", if an undefined ValueType value is passed.
   116  func ValueTypeName(t ValueType) string {
   117  	switch t {
   118  	case ValueTypeI32:
   119  		return "i32"
   120  	case ValueTypeI64:
   121  		return "i64"
   122  	case ValueTypeF32:
   123  		return "f32"
   124  	case ValueTypeF64:
   125  		return "f64"
   126  	case ValueTypeExternref:
   127  		return "externref"
   128  	}
   129  	return "unknown"
   130  }
   131  
   132  // Module is a sandboxed, ready to execute Wasm module. This can be used to get exported functions, etc.
   133  //
   134  // In WebAssembly terminology, this corresponds to a "Module Instance", but wazero calls pre-instantiation module as
   135  // "Compiled Module" as in wazero.CompiledModule, therefore we call this post-instantiation module simply "Module".
   136  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#module-instances%E2%91%A0
   137  //
   138  // # Notes
   139  //
   140  //   - This is an interface for decoupling, not third-party implementations.
   141  //     All implementations are in wazero.
   142  //   - Closing the wazero.Runtime closes any Module it instantiated.
   143  type Module interface {
   144  	fmt.Stringer
   145  
   146  	// Name is the name this module was instantiated with. Exported functions can be imported with this name.
   147  	Name() string
   148  
   149  	// Memory returns a memory defined in this module or nil if there are none wasn't.
   150  	Memory() Memory
   151  
   152  	// ExportedFunction returns a function exported from this module or nil if it wasn't.
   153  	ExportedFunction(name string) Function
   154  
   155  	// ExportedFunctionDefinitions returns all the exported function
   156  	// definitions in this module, keyed on export name.
   157  	ExportedFunctionDefinitions() map[string]FunctionDefinition
   158  
   159  	// TODO: Table
   160  
   161  	// ExportedMemory returns a memory exported from this module or nil if it wasn't.
   162  	//
   163  	// WASI modules require exporting a Memory named "memory". This means that a module successfully initialized
   164  	// as a WASI Command or Reactor will never return nil for this name.
   165  	//
   166  	// See https://github.com/WebAssembly/WASI/blob/snapshot-01/design/application-abi.md#current-unstable-abi
   167  	ExportedMemory(name string) Memory
   168  
   169  	// ExportedMemoryDefinitions returns all the exported memory definitions
   170  	// in this module, keyed on export name.
   171  	//
   172  	// Note: As of WebAssembly Core Specification 2.0, there can be at most one
   173  	// memory.
   174  	ExportedMemoryDefinitions() map[string]MemoryDefinition
   175  
   176  	// ExportedGlobal a global exported from this module or nil if it wasn't.
   177  	ExportedGlobal(name string) Global
   178  
   179  	// CloseWithExitCode releases resources allocated for this Module. Use a non-zero exitCode parameter to indicate a
   180  	// failure to ExportedFunction callers.
   181  	//
   182  	// The error returned here, if present, is about resource de-allocation (such as I/O errors). Only the last error is
   183  	// returned, so a non-nil return means at least one error happened. Regardless of error, this Module will
   184  	// be removed, making its name available again.
   185  	//
   186  	// Calling this inside a host function is safe, and may cause ExportedFunction callers to receive a sys.ExitError
   187  	// with the exitCode.
   188  	CloseWithExitCode(ctx context.Context, exitCode uint32) error
   189  
   190  	// Closer closes this module by delegating to CloseWithExitCode with an exit code of zero.
   191  	Closer
   192  
   193  	internalapi.WazeroOnly
   194  }
   195  
   196  // Closer closes a resource.
   197  //
   198  // # Notes
   199  //
   200  //   - This is an interface for decoupling, not third-party implementations.
   201  //     All implementations are in wazero.
   202  type Closer interface {
   203  	// Close closes the resource.
   204  	//
   205  	// Note: The context parameter is used for value lookup, such as for
   206  	// logging. A canceled or otherwise done context will not prevent Close
   207  	// from succeeding.
   208  	Close(context.Context) error
   209  }
   210  
   211  // ExportDefinition is a WebAssembly type exported in a module
   212  // (wazero.CompiledModule).
   213  //
   214  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#exports%E2%91%A0
   215  //
   216  // # Notes
   217  //
   218  //   - This is an interface for decoupling, not third-party implementations.
   219  //     All implementations are in wazero.
   220  type ExportDefinition interface {
   221  	// ModuleName is the possibly empty name of the module defining this
   222  	// export.
   223  	//
   224  	// Note: This may be different from Module.Name, because a compiled module
   225  	// can be instantiated multiple times as different names.
   226  	ModuleName() string
   227  
   228  	// Index is the position in the module's index, imports first.
   229  	Index() uint32
   230  
   231  	// Import returns true with the module and name when this was imported.
   232  	// Otherwise, it returns false.
   233  	//
   234  	// Note: Empty string is valid for both names in the WebAssembly Core
   235  	// Specification, so "" "" is possible.
   236  	Import() (moduleName, name string, isImport bool)
   237  
   238  	// ExportNames include all exported names.
   239  	//
   240  	// Note: The empty name is allowed in the WebAssembly Core Specification,
   241  	// so "" is possible.
   242  	ExportNames() []string
   243  
   244  	internalapi.WazeroOnly
   245  }
   246  
   247  // MemoryDefinition is a WebAssembly memory exported in a module
   248  // (wazero.CompiledModule). Units are in pages (64KB).
   249  //
   250  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#exports%E2%91%A0
   251  //
   252  // # Notes
   253  //
   254  //   - This is an interface for decoupling, not third-party implementations.
   255  //     All implementations are in wazero.
   256  type MemoryDefinition interface {
   257  	ExportDefinition
   258  
   259  	// Min returns the possibly zero initial count of 64KB pages.
   260  	Min() uint32
   261  
   262  	// Max returns the possibly zero max count of 64KB pages, or false if
   263  	// unbounded.
   264  	Max() (uint32, bool)
   265  
   266  	internalapi.WazeroOnly
   267  }
   268  
   269  // FunctionDefinition is a WebAssembly function exported in a module
   270  // (wazero.CompiledModule).
   271  //
   272  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#exports%E2%91%A0
   273  //
   274  // # Notes
   275  //
   276  //   - This is an interface for decoupling, not third-party implementations.
   277  //     All implementations are in wazero.
   278  type FunctionDefinition interface {
   279  	ExportDefinition
   280  
   281  	// Name is the module-defined name of the function, which is not necessarily
   282  	// the same as its export name.
   283  	Name() string
   284  
   285  	// DebugName identifies this function based on its Index or Name in the
   286  	// module. This is used for errors and stack traces. e.g. "env.abort".
   287  	//
   288  	// When the function name is empty, a substitute name is generated by
   289  	// prefixing '$' to its position in the index. Ex ".$0" is the
   290  	// first function (possibly imported) in an unnamed module.
   291  	//
   292  	// The format is dot-delimited module and function name, but there are no
   293  	// restrictions on the module and function name. This means either can be
   294  	// empty or include dots. e.g. "x.x.x" could mean module "x" and name "x.x",
   295  	// or it could mean module "x.x" and name "x".
   296  	//
   297  	// Note: This name is stable regardless of import or export. For example,
   298  	// if Import returns true, the value is still based on the Name or Index
   299  	// and not the imported function name.
   300  	DebugName() string
   301  
   302  	// GoFunction is non-nil when implemented by the embedder instead of a wasm
   303  	// binary, e.g. via wazero.HostModuleBuilder
   304  	//
   305  	// The expected results are nil, GoFunction or GoModuleFunction.
   306  	GoFunction() interface{}
   307  
   308  	// ParamTypes are the possibly empty sequence of value types accepted by a
   309  	// function with this signature.
   310  	//
   311  	// See ValueType documentation for encoding rules.
   312  	ParamTypes() []ValueType
   313  
   314  	// ParamNames are index-correlated with ParamTypes or nil if not available
   315  	// for one or more parameters.
   316  	ParamNames() []string
   317  
   318  	// ResultTypes are the results of the function.
   319  	//
   320  	// When WebAssembly 1.0 (20191205), there can be at most one result.
   321  	// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#result-types%E2%91%A0
   322  	//
   323  	// See ValueType documentation for encoding rules.
   324  	ResultTypes() []ValueType
   325  
   326  	// ResultNames are index-correlated with ResultTypes or nil if not
   327  	// available for one or more results.
   328  	ResultNames() []string
   329  
   330  	internalapi.WazeroOnly
   331  }
   332  
   333  // Function is a WebAssembly function exported from an instantiated module
   334  // (wazero.Runtime InstantiateModule).
   335  //
   336  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#syntax-func
   337  //
   338  // # Notes
   339  //
   340  //   - This is an interface for decoupling, not third-party implementations.
   341  //     All implementations are in wazero.
   342  type Function interface {
   343  	// Definition is metadata about this function from its defining module.
   344  	Definition() FunctionDefinition
   345  
   346  	// Call invokes the function with the given parameters and returns any
   347  	// results or an error for any failure looking up or invoking the function.
   348  	//
   349  	// Encoding is described in Definition, and supplying an incorrect count of
   350  	// parameters vs FunctionDefinition.ParamTypes is an error.
   351  	//
   352  	// If the exporting Module was closed during this call, the error returned
   353  	// may be a sys.ExitError. See Module.CloseWithExitCode for details.
   354  	//
   355  	// Call is not goroutine-safe, therefore it is recommended to create
   356  	// another Function if you want to invoke the same function concurrently.
   357  	// On the other hand, sequential invocations of Call is allowed.
   358  	//
   359  	// To safely encode/decode params/results expressed as uint64, users are encouraged to
   360  	// use api.EncodeXXX or DecodeXXX functions. See the docs on api.ValueType.
   361  	//
   362  	// When RuntimeConfig.WithCloseOnContextDone is toggled, the invocation of this Call method is ensured to be closed
   363  	// whenever one of the three conditions is met. In the event of close, sys.ExitError will be returned and
   364  	// the api.Module from which this api.Function is derived will be made closed. See the documentation of
   365  	// WithCloseOnContextDone on wazero.RuntimeConfig for detail. See examples in context_done_example_test.go for
   366  	// the end-to-end demonstrations of how these terminations can be performed.
   367  	Call(ctx context.Context, params ...uint64) ([]uint64, error)
   368  
   369  	// CallWithStack is an optimized variation of Call that saves memory
   370  	// allocations when the stack slice is reused across calls.
   371  	//
   372  	// Stack length must be at least the max of parameter or result length.
   373  	// The caller adds parameters in order to the stack, and reads any results
   374  	// in order from the stack, except in the error case.
   375  	//
   376  	// For example, the following reuses the same stack slice to call searchFn
   377  	// repeatedly saving one allocation per iteration:
   378  	//
   379  	//	stack := make([]uint64, 4)
   380  	//	for i, search := range searchParams {
   381  	//		// copy the next params to the stack
   382  	//		copy(stack, search)
   383  	//		if err := searchFn.CallWithStack(ctx, stack); err != nil {
   384  	//			return err
   385  	//		} else if stack[0] == 1 { // found
   386  	//			return i // searchParams[i] matched!
   387  	//		}
   388  	//	}
   389  	//
   390  	// # Notes
   391  	//
   392  	//   - This is similar to GoModuleFunction, except for using calling functions
   393  	//     instead of implementing them. Moreover, this is used regardless of
   394  	//     whether the callee is a host or wasm defined function.
   395  	CallWithStack(ctx context.Context, stack []uint64) error
   396  
   397  	internalapi.WazeroOnly
   398  }
   399  
   400  // GoModuleFunction is a Function implemented in Go instead of a wasm binary.
   401  // The Module parameter is the calling module, used to access memory or
   402  // exported functions. See GoModuleFunc for an example.
   403  //
   404  // The stack is includes any parameters encoded according to their ValueType.
   405  // Its length is the max of parameter or result length. When there are results,
   406  // write them in order beginning at index zero. Do not use the stack after the
   407  // function returns.
   408  //
   409  // Here's a typical way to read three parameters and write back one.
   410  //
   411  //	// read parameters off the stack in index order
   412  //	argv, argvBuf := api.DecodeU32(stack[0]), api.DecodeU32(stack[1])
   413  //
   414  //	// write results back to the stack in index order
   415  //	stack[0] = api.EncodeU32(ErrnoSuccess)
   416  //
   417  // This function can be non-deterministic or cause side effects. It also
   418  // has special properties not defined in the WebAssembly Core specification.
   419  // Notably, this uses the caller's memory (via Module.Memory). See
   420  // https://www.w3.org/TR/wasm-core-1/#host-functions%E2%91%A0
   421  //
   422  // Most end users will not define functions directly with this, as they will
   423  // use reflection or code generators instead. These approaches are more
   424  // idiomatic as they can map go types to ValueType. This type is exposed for
   425  // those willing to trade usability and safety for performance.
   426  //
   427  // To safely decode/encode values from/to the uint64 stack, users are encouraged to use
   428  // api.EncodeXXX or api.DecodeXXX functions. See the docs on api.ValueType.
   429  type GoModuleFunction interface {
   430  	Call(ctx context.Context, mod Module, stack []uint64)
   431  }
   432  
   433  // GoModuleFunc is a convenience for defining an inlined function.
   434  //
   435  // For example, the following returns an uint32 value read from parameter zero:
   436  //
   437  //	api.GoModuleFunc(func(ctx context.Context, mod api.Module, stack []uint64) {
   438  //		offset := api.DecodeU32(stack[0]) // read the parameter from the stack
   439  //
   440  //		ret, ok := mod.Memory().ReadUint32Le(offset)
   441  //		if !ok {
   442  //			panic("out of memory")
   443  //		}
   444  //
   445  //		stack[0] = api.EncodeU32(ret) // add the result back to the stack.
   446  //	})
   447  type GoModuleFunc func(ctx context.Context, mod Module, stack []uint64)
   448  
   449  // Call implements GoModuleFunction.Call.
   450  func (f GoModuleFunc) Call(ctx context.Context, mod Module, stack []uint64) {
   451  	f(ctx, mod, stack)
   452  }
   453  
   454  // GoFunction is an optimized form of GoModuleFunction which doesn't require
   455  // the Module parameter. See GoFunc for an example.
   456  //
   457  // For example, this function does not need to use the importing module's
   458  // memory or exported functions.
   459  type GoFunction interface {
   460  	Call(ctx context.Context, stack []uint64)
   461  }
   462  
   463  // GoFunc is a convenience for defining an inlined function.
   464  //
   465  // For example, the following returns the sum of two uint32 parameters:
   466  //
   467  //	api.GoFunc(func(ctx context.Context, stack []uint64) {
   468  //		x, y := api.DecodeU32(stack[0]), api.DecodeU32(stack[1])
   469  //		stack[0] = api.EncodeU32(x + y)
   470  //	})
   471  type GoFunc func(ctx context.Context, stack []uint64)
   472  
   473  // Call implements GoFunction.Call.
   474  func (f GoFunc) Call(ctx context.Context, stack []uint64) {
   475  	f(ctx, stack)
   476  }
   477  
   478  // Global is a WebAssembly 1.0 (20191205) global exported from an instantiated module (wazero.Runtime InstantiateModule).
   479  //
   480  // For example, if the value is not mutable, you can read it once:
   481  //
   482  //	offset := module.ExportedGlobal("memory.offset").Get()
   483  //
   484  // Globals are allowed by specification to be mutable. However, this can be disabled by configuration. When in doubt,
   485  // safe cast to find out if the value can change. Here's an example:
   486  //
   487  //	offset := module.ExportedGlobal("memory.offset")
   488  //	if _, ok := offset.(api.MutableGlobal); ok {
   489  //		// value can change
   490  //	} else {
   491  //		// value is constant
   492  //	}
   493  //
   494  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#globals%E2%91%A0
   495  //
   496  // # Notes
   497  //
   498  //   - This is an interface for decoupling, not third-party implementations.
   499  //     All implementations are in wazero.
   500  type Global interface {
   501  	fmt.Stringer
   502  
   503  	// Type describes the numeric type of the global.
   504  	Type() ValueType
   505  
   506  	// Get returns the last known value of this global.
   507  	//
   508  	// See Type for how to decode this value to a Go type.
   509  	Get() uint64
   510  }
   511  
   512  // MutableGlobal is a Global whose value can be updated at runtime (variable).
   513  //
   514  // # Notes
   515  //
   516  //   - This is an interface for decoupling, not third-party implementations.
   517  //     All implementations are in wazero.
   518  type MutableGlobal interface {
   519  	Global
   520  
   521  	// Set updates the value of this global.
   522  	//
   523  	// See Global.Type for how to encode this value from a Go type.
   524  	Set(v uint64)
   525  
   526  	internalapi.WazeroOnly
   527  }
   528  
   529  // Memory allows restricted access to a module's memory. Notably, this does not allow growing.
   530  //
   531  // See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#storage%E2%91%A0
   532  //
   533  // # Notes
   534  //
   535  //   - This is an interface for decoupling, not third-party implementations.
   536  //     All implementations are in wazero.
   537  //   - This includes all value types available in WebAssembly 1.0 (20191205) and all are encoded little-endian.
   538  type Memory interface {
   539  	// Definition is metadata about this memory from its defining module.
   540  	Definition() MemoryDefinition
   541  
   542  	// Size returns the size in bytes available. e.g. If the underlying memory
   543  	// has 1 page: 65536
   544  	//
   545  	// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#-hrefsyntax-instr-memorymathsfmemorysize%E2%91%A0
   546  	Size() uint32
   547  
   548  	// Grow increases memory by the delta in pages (65536 bytes per page).
   549  	// The return val is the previous memory size in pages, or false if the
   550  	// delta was ignored as it exceeds MemoryDefinition.Max.
   551  	//
   552  	// # Notes
   553  	//
   554  	//   - This is the same as the "memory.grow" instruction defined in the
   555  	//	  WebAssembly Core Specification, except returns false instead of -1.
   556  	//   - When this returns true, any shared views via Read must be refreshed.
   557  	//
   558  	// See MemorySizer Read and https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#grow-mem
   559  	Grow(deltaPages uint32) (previousPages uint32, ok bool)
   560  
   561  	// ReadByte reads a single byte from the underlying buffer at the offset or returns false if out of range.
   562  	ReadByte(offset uint32) (byte, bool)
   563  
   564  	// ReadUint16Le reads a uint16 in little-endian encoding from the underlying buffer at the offset in or returns
   565  	// false if out of range.
   566  	ReadUint16Le(offset uint32) (uint16, bool)
   567  
   568  	// ReadUint32Le reads a uint32 in little-endian encoding from the underlying buffer at the offset in or returns
   569  	// false if out of range.
   570  	ReadUint32Le(offset uint32) (uint32, bool)
   571  
   572  	// ReadFloat32Le reads a float32 from 32 IEEE 754 little-endian encoded bits in the underlying buffer at the offset
   573  	// or returns false if out of range.
   574  	// See math.Float32bits
   575  	ReadFloat32Le(offset uint32) (float32, bool)
   576  
   577  	// ReadUint64Le reads a uint64 in little-endian encoding from the underlying buffer at the offset or returns false
   578  	// if out of range.
   579  	ReadUint64Le(offset uint32) (uint64, bool)
   580  
   581  	// ReadFloat64Le reads a float64 from 64 IEEE 754 little-endian encoded bits in the underlying buffer at the offset
   582  	// or returns false if out of range.
   583  	//
   584  	// See math.Float64bits
   585  	ReadFloat64Le(offset uint32) (float64, bool)
   586  
   587  	// Read reads byteCount bytes from the underlying buffer at the offset or
   588  	// returns false if out of range.
   589  	//
   590  	// For example, to search for a NUL-terminated string:
   591  	//	buf, _ = memory.Read(offset, byteCount)
   592  	//	n := bytes.IndexByte(buf, 0)
   593  	//	if n < 0 {
   594  	//		// Not found!
   595  	//	}
   596  	//
   597  	// Write-through
   598  	//
   599  	// This returns a view of the underlying memory, not a copy. This means any
   600  	// writes to the slice returned are visible to Wasm, and any updates from
   601  	// Wasm are visible reading the returned slice.
   602  	//
   603  	// For example:
   604  	//	buf, _ = memory.Read(offset, byteCount)
   605  	//	buf[1] = 'a' // writes through to memory, meaning Wasm code see 'a'.
   606  	//
   607  	// If you don't intend-write through, make a copy of the returned slice.
   608  	//
   609  	// When to refresh Read
   610  	//
   611  	// The returned slice disconnects on any capacity change. For example,
   612  	// `buf = append(buf, 'a')` might result in a slice that is no longer
   613  	// shared. The same exists Wasm side. For example, if Wasm changes its
   614  	// memory capacity, ex via "memory.grow"), the host slice is no longer
   615  	// shared. Those who need a stable view must set Wasm memory min=max, or
   616  	// use wazero.RuntimeConfig WithMemoryCapacityPages to ensure max is always
   617  	// allocated.
   618  	Read(offset, byteCount uint32) ([]byte, bool)
   619  
   620  	// WriteByte writes a single byte to the underlying buffer at the offset in or returns false if out of range.
   621  	WriteByte(offset uint32, v byte) bool
   622  
   623  	// WriteUint16Le writes the value in little-endian encoding to the underlying buffer at the offset in or returns
   624  	// false if out of range.
   625  	WriteUint16Le(offset uint32, v uint16) bool
   626  
   627  	// WriteUint32Le writes the value in little-endian encoding to the underlying buffer at the offset in or returns
   628  	// false if out of range.
   629  	WriteUint32Le(offset, v uint32) bool
   630  
   631  	// WriteFloat32Le writes the value in 32 IEEE 754 little-endian encoded bits to the underlying buffer at the offset
   632  	// or returns false if out of range.
   633  	//
   634  	// See math.Float32bits
   635  	WriteFloat32Le(offset uint32, v float32) bool
   636  
   637  	// WriteUint64Le writes the value in little-endian encoding to the underlying buffer at the offset in or returns
   638  	// false if out of range.
   639  	WriteUint64Le(offset uint32, v uint64) bool
   640  
   641  	// WriteFloat64Le writes the value in 64 IEEE 754 little-endian encoded bits to the underlying buffer at the offset
   642  	// or returns false if out of range.
   643  	//
   644  	// See math.Float64bits
   645  	WriteFloat64Le(offset uint32, v float64) bool
   646  
   647  	// Write writes the slice to the underlying buffer at the offset or returns false if out of range.
   648  	Write(offset uint32, v []byte) bool
   649  
   650  	// WriteString writes the string to the underlying buffer at the offset or returns false if out of range.
   651  	WriteString(offset uint32, v string) bool
   652  
   653  	internalapi.WazeroOnly
   654  }
   655  
   656  // CustomSection contains the name and raw data of a custom section.
   657  //
   658  // # Notes
   659  //
   660  //   - This is an interface for decoupling, not third-party implementations.
   661  //     All implementations are in wazero.
   662  type CustomSection interface {
   663  	// Name is the name of the custom section
   664  	Name() string
   665  	// Data is the raw data of the custom section
   666  	Data() []byte
   667  
   668  	internalapi.WazeroOnly
   669  }
   670  
   671  // EncodeExternref encodes the input as a ValueTypeExternref.
   672  //
   673  // See DecodeExternref
   674  func EncodeExternref(input uintptr) uint64 {
   675  	return uint64(input)
   676  }
   677  
   678  // DecodeExternref decodes the input as a ValueTypeExternref.
   679  //
   680  // See EncodeExternref
   681  func DecodeExternref(input uint64) uintptr {
   682  	return uintptr(input)
   683  }
   684  
   685  // EncodeI32 encodes the input as a ValueTypeI32.
   686  func EncodeI32(input int32) uint64 {
   687  	return uint64(uint32(input))
   688  }
   689  
   690  // DecodeI32 decodes the input as a ValueTypeI32.
   691  func DecodeI32(input uint64) int32 {
   692  	return int32(input)
   693  }
   694  
   695  // EncodeU32 encodes the input as a ValueTypeI32.
   696  func EncodeU32(input uint32) uint64 {
   697  	return uint64(input)
   698  }
   699  
   700  // DecodeU32 decodes the input as a ValueTypeI32.
   701  func DecodeU32(input uint64) uint32 {
   702  	return uint32(input)
   703  }
   704  
   705  // EncodeI64 encodes the input as a ValueTypeI64.
   706  func EncodeI64(input int64) uint64 {
   707  	return uint64(input)
   708  }
   709  
   710  // EncodeF32 encodes the input as a ValueTypeF32.
   711  //
   712  // See DecodeF32
   713  func EncodeF32(input float32) uint64 {
   714  	return uint64(math.Float32bits(input))
   715  }
   716  
   717  // DecodeF32 decodes the input as a ValueTypeF32.
   718  //
   719  // See EncodeF32
   720  func DecodeF32(input uint64) float32 {
   721  	return math.Float32frombits(uint32(input))
   722  }
   723  
   724  // EncodeF64 encodes the input as a ValueTypeF64.
   725  //
   726  // See EncodeF32
   727  func EncodeF64(input float64) uint64 {
   728  	return math.Float64bits(input)
   729  }
   730  
   731  // DecodeF64 decodes the input as a ValueTypeF64.
   732  //
   733  // See EncodeF64
   734  func DecodeF64(input uint64) float64 {
   735  	return math.Float64frombits(input)
   736  }