extend stdlib to allow import of more packages (#1099)

* stdlib: extend stdlib to allow import of more packages

Author: Cornel

src/os/env.go

@@ -0,0 +1,5 @@
+package os
+
+func Getenv(key string) string {
+	return ""
+}

src/os/errors.go

@@ -0,0 +1,39 @@
+package os
+
+import (
+	"errors"
+)
+
+var (
+	ErrInvalid    = errors.New("invalid argument")
+	ErrPermission = errors.New("permission denied")
+	ErrClosed     = errors.New("file already closed")
+
+	// Portable analogs of some common system call errors.
+	// Note that these are exported for use in the Filesystem interface.
+	ErrUnsupported    = errors.New("operation not supported")
+	ErrNotImplemented = errors.New("operation not implemented")
+	ErrNotExist       = errors.New("file not found")
+	ErrExist          = errors.New("file exists")
+)
+
+func IsPermission(err error) bool {
+	return err == ErrPermission
+}
+
+func NewSyscallError(syscall string, err error) error {
+	if err == nil {
+		return nil
+	}
+	return &SyscallError{syscall, err}
+}
+
+// SyscallError records an error from a specific system call.
+type SyscallError struct {
+	Syscall string
+	Err     error
+}
+
+func (e *SyscallError) Error() string { return e.Syscall + ": " + e.Err.Error() }
+
+func (e *SyscallError) Unwrap() error { return e.Err }

src/os/exec.go

@@ -0,0 +1,6 @@
+package os
+
+type Signal interface {
+	String() string
+	Signal() // to distinguish from other Stringers
+}

src/os/file.go

@@ -6,16 +6,7 @@
 package os
 
 import (
-	"errors"
-)
-
-// Portable analogs of some common system call errors.
-// Note that these are exported for use in the Filesystem interface.
-var (
-	ErrUnsupported    = errors.New("operation not supported")
-	ErrNotImplemented = errors.New("operation not implemented")
-	ErrNotExist       = errors.New("file not found")
-	ErrExist          = errors.New("file exists")
+	"syscall"
 )
 
 // Mkdir creates a directory. If the operation fails, it will return an error of
@@ -91,6 +82,10 @@ func (f *File) Read(b []byte) (n int, err error) {
 	return
 }
 
+func (f *File) ReadAt(b []byte, off int64) (n int, err error) {
+	return 0, ErrNotImplemented
+}
+
 // Write writes len(b) bytes to the File. It returns the number of bytes written
 // and an error, if any. Write returns a non-nil error when n != len(b).
 func (f *File) Write(b []byte) (n int, err error) {
@@ -125,6 +120,20 @@ func (f *File) Stat() (FileInfo, error) {
 	return nil, &PathError{"stat", f.name, ErrNotImplemented}
 }
 
+// Sync is a stub, not yet implemented
+func (f *File) Sync() error {
+	return ErrNotImplemented
+}
+
+func (f *File) SyscallConn() (syscall.RawConn, error) {
+	return nil, ErrNotImplemented
+}
+
+// Fd returns the file handle referencing the open file.
+func (f *File) Fd() uintptr {
+	panic("unimplemented: os.file.Fd()")
+}
+
 const (
 	PathSeparator     = '/' // OS-specific path separator
 	PathListSeparator = ':' // OS-specific path list separator
@@ -194,7 +203,7 @@ type FileInfo interface {
 	Name() string   // base name of the file
 	Size() int64    // length in bytes for regular files; system-dependent for others
 	Mode() FileMode // file mode bits
-	// ModTime() time.Time // modification time
+	// TODO ModTime() time.Time // modification time
 	IsDir() bool      // abbreviation for Mode().IsDir()
 	Sys() interface{} // underlying data source (can return nil)
 }

src/os/sys.go

@@ -0,0 +1,5 @@
+package os
+
+func Hostname() (name string, err error) {
+	return "", ErrNotImplemented
+}

src/reflect/deepequal.go

@@ -0,0 +1,9 @@
+package reflect
+
+func DeepEqual(x, y interface{}) bool {
+	if x == nil || y == nil {
+		return x == y
+	}
+
+	panic("unimplemented: reflect.DeepEqual()")
+}

src/reflect/strconv.go

@@ -0,0 +1,248 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package reflect
+
+import (
+	"unicode/utf8"
+)
+
+// errSyntax indicates that a value does not have the right syntax for the target type.
+var errSyntax = badSyntax{}
+
+type badSyntax struct{}
+
+func (badSyntax) Error() string {
+	return "invalid syntax"
+}
+
+func unhex(b byte) (v rune, ok bool) {
+	c := rune(b)
+	switch {
+	case '0' <= c && c <= '9':
+		return c - '0', true
+	case 'a' <= c && c <= 'f':
+		return c - 'a' + 10, true
+	case 'A' <= c && c <= 'F':
+		return c - 'A' + 10, true
+	}
+	return
+}
+
+// unquoteChar decodes the first character or byte in the escaped string
+// or character literal represented by the string s.
+// It returns four values:
+//
+//	1) value, the decoded Unicode code point or byte value;
+//	2) multibyte, a boolean indicating whether the decoded character requires a multibyte UTF-8 representation;
+//	3) tail, the remainder of the string after the character; and
+//	4) an error that will be nil if the character is syntactically valid.
+//
+// The second argument, quote, specifies the type of literal being parsed
+// and therefore which escaped quote character is permitted.
+// If set to a single quote, it permits the sequence \' and disallows unescaped '.
+// If set to a double quote, it permits \" and disallows unescaped ".
+// If set to zero, it does not permit either escape and allows both quote characters to appear unescaped.
+func unquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error) {
+	// easy cases
+	if len(s) == 0 {
+		err = errSyntax
+		return
+	}
+	switch c := s[0]; {
+	case c == quote && (quote == '\'' || quote == '"'):
+		err = errSyntax
+		return
+	case c >= utf8.RuneSelf:
+		r, size := utf8.DecodeRuneInString(s)
+		return r, true, s[size:], nil
+	case c != '\\':
+		return rune(s[0]), false, s[1:], nil
+	}
+
+	// hard case: c is backslash
+	if len(s) <= 1 {
+		err = errSyntax
+		return
+	}
+	c := s[1]
+	s = s[2:]
+
+	switch c {
+	case 'a':
+		value = '\a'
+	case 'b':
+		value = '\b'
+	case 'f':
+		value = '\f'
+	case 'n':
+		value = '\n'
+	case 'r':
+		value = '\r'
+	case 't':
+		value = '\t'
+	case 'v':
+		value = '\v'
+	case 'x', 'u', 'U':
+		n := 0
+		switch c {
+		case 'x':
+			n = 2
+		case 'u':
+			n = 4
+		case 'U':
+			n = 8
+		}
+		var v rune
+		if len(s) < n {
+			err = errSyntax
+			return
+		}
+		for j := 0; j < n; j++ {
+			x, ok := unhex(s[j])
+			if !ok {
+				err = errSyntax
+				return
+			}
+			v = v<<4 | x
+		}
+		s = s[n:]
+		if c == 'x' {
+			// single-byte string, possibly not UTF-8
+			value = v
+			break
+		}
+		if v > utf8.MaxRune {
+			err = errSyntax
+			return
+		}
+		value = v
+		multibyte = true
+	case '0', '1', '2', '3', '4', '5', '6', '7':
+		v := rune(c) - '0'
+		if len(s) < 2 {
+			err = errSyntax
+			return
+		}
+		for j := 0; j < 2; j++ { // one digit already; two more
+			x := rune(s[j]) - '0'
+			if x < 0 || x > 7 {
+				err = errSyntax
+				return
+			}
+			v = (v << 3) | x
+		}
+		s = s[2:]
+		if v > 255 {
+			err = errSyntax
+			return
+		}
+		value = v
+	case '\\':
+		value = '\\'
+	case '\'', '"':
+		if c != quote {
+			err = errSyntax
+			return
+		}
+		value = rune(c)
+	default:
+		err = errSyntax
+		return
+	}
+	tail = s
+	return
+}
+
+// unquote interprets s as a single-quoted, double-quoted,
+// or backquoted Go string literal, returning the string value
+// that s quotes.  (If s is single-quoted, it would be a Go
+// character literal; unquote returns the corresponding
+// one-character string.)
+func unquote(s string) (string, error) {
+	n := len(s)
+	if n < 2 {
+		return "", errSyntax
+	}
+	quote := s[0]
+	if quote != s[n-1] {
+		return "", errSyntax
+	}
+	s = s[1 : n-1]
+
+	if quote == '`' {
+		if contains(s, '`') {
+			return "", errSyntax
+		}
+		if contains(s, '\r') {
+			// -1 because we know there is at least one \r to remove.
+			buf := make([]byte, 0, len(s)-1)
+			for i := 0; i < len(s); i++ {
+				if s[i] != '\r' {
+					buf = append(buf, s[i])
+				}
+			}
+			return string(buf), nil
+		}
+		return s, nil
+	}
+	if quote != '"' && quote != '\'' {
+		return "", errSyntax
+	}
+	if contains(s, '\n') {
+		return "", errSyntax
+	}
+
+	// Is it trivial? Avoid allocation.
+	if !contains(s, '\\') && !contains(s, quote) {
+		switch quote {
+		case '"':
+			if utf8.ValidString(s) {
+				return s, nil
+			}
+		case '\'':
+			r, size := utf8.DecodeRuneInString(s)
+			if size == len(s) && (r != utf8.RuneError || size != 1) {
+				return s, nil
+			}
+		}
+	}
+
+	var runeTmp [utf8.UTFMax]byte
+	buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
+	for len(s) > 0 {
+		c, multibyte, ss, err := unquoteChar(s, quote)
+		if err != nil {
+			return "", err
+		}
+		s = ss
+		if c < utf8.RuneSelf || !multibyte {
+			buf = append(buf, byte(c))
+		} else {
+			n := utf8.EncodeRune(runeTmp[:], c)
+			buf = append(buf, runeTmp[:n]...)
+		}
+		if quote == '\'' && len(s) != 0 {
+			// single-quoted must be single character
+			return "", errSyntax
+		}
+	}
+	return string(buf), nil
+}
+
+// contains reports whether the string contains the byte c.
+func contains(s string, c byte) bool {
+	return indexByteString(s, c) != -1
+}
+
+// Index finds the index of the first instance of the specified byte in the string.
+// If the byte is not found, this returns -1.
+func indexByteString(s string, c byte) int {
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			return i
+		}
+	}
+	return -1
+}