156 lines
3.4 KiB
Go
156 lines
3.4 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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// The Error interface identifies a run time error.
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type Error interface {
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error
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// RuntimeError is a no-op function but
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// serves to distinguish types that are runtime
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// errors from ordinary errors: a type is a
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// runtime error if it has a RuntimeError method.
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RuntimeError()
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}
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// A TypeAssertionError explains a failed type assertion.
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type TypeAssertionError struct {
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interfaceString string
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concreteString string
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assertedString string
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missingMethod string // one method needed by Interface, missing from Concrete
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}
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func (*TypeAssertionError) RuntimeError() {}
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func (e *TypeAssertionError) Error() string {
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inter := e.interfaceString
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if inter == "" {
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inter = "interface"
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}
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if e.concreteString == "" {
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return "interface conversion: " + inter + " is nil, not " + e.assertedString
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}
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if e.missingMethod == "" {
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return "interface conversion: " + inter + " is " + e.concreteString +
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", not " + e.assertedString
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}
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return "interface conversion: " + e.concreteString + " is not " + e.assertedString +
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": missing method " + e.missingMethod
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}
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// For calling from C.
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func NewTypeAssertionError(ps1, ps2, ps3 *string, pmeth *string, ret *interface{}) {
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var s1, s2, s3, meth string
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if ps1 != nil {
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s1 = *ps1
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}
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if ps2 != nil {
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s2 = *ps2
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}
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if ps3 != nil {
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s3 = *ps3
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}
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if pmeth != nil {
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meth = *pmeth
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}
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// For gccgo, strip out quoted strings.
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s1 = unquote(s1)
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s2 = unquote(s2)
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s3 = unquote(s3)
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*ret = &TypeAssertionError{s1, s2, s3, meth}
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}
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// Remove quoted strings from gccgo reflection strings.
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func unquote(s string) string {
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ls := len(s)
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var i int
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for i = 0; i < ls; i++ {
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if s[i] == '\t' {
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break
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}
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}
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if i == ls {
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return s
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}
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var q bool
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r := make([]byte, len(s))
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j := 0
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for i = 0; i < ls; i++ {
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if s[i] == '\t' {
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q = !q
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} else if !q {
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r[j] = s[i]
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j++
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}
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}
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return string(r[:j])
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}
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// An errorString represents a runtime error described by a single string.
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type errorString string
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func (e errorString) RuntimeError() {}
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func (e errorString) Error() string {
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return "runtime error: " + string(e)
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}
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// For calling from C.
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func NewErrorString(s string, ret *interface{}) {
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*ret = errorString(s)
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}
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// An errorCString represents a runtime error described by a single C string.
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type errorCString uintptr
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func (e errorCString) RuntimeError() {}
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func cstringToGo(uintptr) string
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func (e errorCString) Error() string {
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return "runtime error: " + cstringToGo(uintptr(e))
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}
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// For calling from C.
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func NewErrorCString(s uintptr, ret *interface{}) {
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*ret = errorCString(s)
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}
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type stringer interface {
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String() string
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}
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func typestring(interface{}) string
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// For calling from C.
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// Prints an argument passed to panic.
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// There's room for arbitrary complexity here, but we keep it
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// simple and handle just a few important cases: int, string, and Stringer.
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func Printany(i interface{}) {
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switch v := i.(type) {
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case nil:
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print("nil")
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case stringer:
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print(v.String())
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case error:
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print(v.Error())
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case int:
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print(v)
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case string:
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print(v)
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default:
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print("(", typestring(i), ") ", i)
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}
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}
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// called from generated code
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func panicwrap(pkg, typ, meth string) {
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panic("value method " + pkg + "." + typ + "." + meth + " called using nil *" + typ + " pointer")
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}
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