💥 update: use syscall.Errno-based error code

config.go

@@ -8,7 +8,6 @@ import (
 
 	"github.com/gaukas/water/configbuilder"
 	"github.com/gaukas/water/internal/log"
-	"github.com/gaukas/water/internal/wasm"
 	"google.golang.org/protobuf/proto"
 )
 
@@ -46,7 +45,7 @@ type Config struct {
 	// Caller is supposed to call c.ModuleConfig() to get the pointer to the
 	// ModuleConfigFactory. If the pointer is nil, a new ModuleConfigFactory will
 	// be created and returned.
-	ModuleConfigFactory *wasm.ModuleConfigFactory
+	ModuleConfigFactory *WazeroModuleConfigFactory
 
 	OverrideLogger *log.Logger // essentially a *slog.Logger, currently using an alias to flatten the version discrepancy
 }
@@ -100,9 +99,9 @@ func (c *Config) WATMBinOrPanic() []byte {
 
 // ModuleConfig returns the ModuleConfigFactory. If the pointer is
 // nil, a new ModuleConfigFactory will be created and returned.
-func (c *Config) ModuleConfig() *wasm.ModuleConfigFactory {
+func (c *Config) ModuleConfig() *WazeroModuleConfigFactory {
 	if c.ModuleConfigFactory == nil {
-		c.ModuleConfigFactory = wasm.NewModuleConfigFactory()
+		c.ModuleConfigFactory = NewWazeroModuleConfigFactory()
 
 		// by default, stdout and stderr are inherited
 		c.ModuleConfigFactory.InheritStdout()
@@ -161,7 +160,7 @@ func (c *Config) UnmarshalJSON(data []byte) error {
 		}
 	}
 
-	c.ModuleConfigFactory = wasm.NewModuleConfigFactory()
+	c.ModuleConfigFactory = NewWazeroModuleConfigFactory()
 	if len(confJson.Module.Argv) > 0 {
 		c.ModuleConfigFactory.SetArgv(confJson.Module.Argv)
 	}
@@ -228,7 +227,7 @@ func (c *Config) UnmarshalProto(b []byte) error {
 	}
 
 	// Parse ModuleConfigFactory
-	c.ModuleConfigFactory = wasm.NewModuleConfigFactory()
+	c.ModuleConfigFactory = NewWazeroModuleConfigFactory()
 	if len(confProto.GetModule().GetArgv()) > 0 {
 		c.ModuleConfigFactory.SetArgv(confProto.Module.Argv)
 	}

internal/wasip1/README.md

@@ -0,0 +1,3 @@
+# `wasip1` package
+
+This package is mostly copied from Go standard library `syscall` package for `wasip1` target, and is a duplicate to `watm/wasip1` package. We choose to maintain a separate package for `wasip1` target to avoid import cycle (`watm` may import `water` for some example/demo code).

internal/wasip1/errno.go

@@ -0,0 +1,51 @@
+package wasip1
+
+import (
+	"fmt"
+	"syscall"
+)
+
+// errno is just a copy of syscall.Errno from the Go standard library.
+//
+// The values are defined in syscall/tables_wasip1.go.
+type errno syscall.Errno
+
+// DecodeWATERError converts a error code returned by WATER API
+// into a syscall.Errno or a higher-level error in Go.
+//
+// It automatically detects whether the error code is a WATER error
+// or a success code (positive). In case of a success code, it
+// returns the code itself and a nil error.
+func DecodeWATERError(errorCode int32) (n int32, err error) {
+	if errorCode >= 0 {
+		n = errorCode // such that when error code is 0, it will return 0, nil
+	} else {
+		errorCode = -errorCode // flip the sign
+		if errno, ok := mapErrno2Syscall[errno(errorCode)]; ok {
+			// if the negative of the error code is a valid Errno, then it is a valid WATERErrno.
+			err = errno
+
+			// TODO: convert some special error codes to higher-level errors.
+		} else {
+			// otherwise, it is an unknown error code.
+			err = fmt.Errorf("unknown WATERErrno %d", errorCode)
+		}
+	}
+	return
+}
+
+func EncodeWATERError(errno syscall.Errno) int32 {
+	if errno == 0 {
+		return 0
+	}
+
+	// first find the corresponding Errno (there might
+	// be missing Errno in the map, which means they
+	// are not supported)
+	if foundErrno, ok := mapSyscall2Errno[errno]; ok {
+		// then convert it to the negative value of itself
+		return -int32(foundErrno)
+	}
+	// if the errno is not found, then it is an unknown error
+	return -int32(syscall.ENOSYS)
+}