util.go

Documentation: github.com/tetratelabs/wazero/internal/gojs/util

     1  package util
     2  
     3  import (
     4  	"fmt"
     5  	pathutil "path"
     6  
     7  	"github.com/tetratelabs/wazero/api"
     8  	"github.com/tetratelabs/wazero/internal/gojs/custom"
     9  	"github.com/tetratelabs/wazero/internal/wasm"
    10  )
    11  
    12  // MustWrite is like api.Memory except that it panics if the offset
    13  // is out of range.
    14  func MustWrite(mem api.Memory, fieldName string, offset uint32, val []byte) {
    15  	if ok := mem.Write(offset, val); !ok {
    16  		panic(fmt.Errorf("out of memory writing %s", fieldName))
    17  	}
    18  }
    19  
    20  // MustRead is like api.Memory except that it panics if the offset and
    21  // byteCount are out of range.
    22  func MustRead(mem api.Memory, funcName string, paramIdx int, offset, byteCount uint32) []byte {
    23  	buf, ok := mem.Read(offset, byteCount)
    24  	if ok {
    25  		return buf
    26  	}
    27  	var paramName string
    28  	if names, ok := custom.NameSection[funcName]; ok {
    29  		if paramIdx < len(names.ParamNames) {
    30  			paramName = names.ParamNames[paramIdx]
    31  		}
    32  	}
    33  	if paramName == "" {
    34  		paramName = fmt.Sprintf("%s param[%d]", funcName, paramIdx)
    35  	}
    36  	panic(fmt.Errorf("out of memory reading %s", paramName))
    37  }
    38  
    39  func NewFunc(name string, goFunc api.GoModuleFunc) *wasm.HostFunc {
    40  	return &wasm.HostFunc{
    41  		ExportName: name,
    42  		Name:       name,
    43  		ParamTypes: []api.ValueType{api.ValueTypeI32},
    44  		ParamNames: []string{"sp"},
    45  		Code:       wasm.Code{GoFunc: goFunc},
    46  	}
    47  }
    48  
    49  // ResolvePath is needed when a non-absolute path is given to a function.
    50  // Unlike other host ABI, GOOS=js maintains the CWD host side.
    51  func ResolvePath(cwd, path string) (resolved string) {
    52  	pathLen := len(path)
    53  	switch {
    54  	case pathLen == 0:
    55  		return cwd
    56  	case pathLen == 1 && path[0] == '.':
    57  		return cwd
    58  	case path[0] == '/':
    59  		resolved = pathutil.Clean(path)
    60  	default:
    61  		resolved = pathutil.Join(cwd, path)
    62  	}
    63  
    64  	// If there's a trailing slash, we need to retain it for symlink edge
    65  	// cases. See https://github.com/golang/go/issues/27225
    66  	if len(resolved) > 1 && path[pathLen-1] == '/' {
    67  		return resolved + "/"
    68  	}
    69  	return resolved
    70  }
    71
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