// Copyright 2019 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 http

import (
	"mime/multipart"
	"net/textproto"
	"net/url"
	_ "unsafe" // for linkname
)

// cloneURLValues should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/searKing/golang
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname cloneURLValues
func cloneURLValues(v url.Values) url.Values {
	if v == nil {
		return nil
	}
	// http.Header and url.Values have the same representation, so temporarily
	// treat it like http.Header, which does have a clone:
	return url.Values(Header(v).Clone())
}

// cloneURL should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/searKing/golang
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname cloneURL
func cloneURL(u *url.URL) *url.URL {
	if u == nil {
		return nil
	}
	u2 := new(url.URL)
	*u2 = *u
	if u.User != nil {
		u2.User = new(url.Userinfo)
		*u2.User = *u.User
	}
	return u2
}

// cloneMultipartForm should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/searKing/golang
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname cloneMultipartForm
func cloneMultipartForm(f *multipart.Form) *multipart.Form {
	if f == nil {
		return nil
	}
	f2 := &multipart.Form{
		Value: (map[string][]string)(Header(f.Value).Clone()),
	}
	if f.File != nil {
		m := make(map[string][]*multipart.FileHeader)
		for k, vv := range f.File {
			vv2 := make([]*multipart.FileHeader, len(vv))
			for i, v := range vv {
				vv2[i] = cloneMultipartFileHeader(v)
			}
			m[k] = vv2
		}
		f2.File = m
	}
	return f2
}

// cloneMultipartFileHeader should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/searKing/golang
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname cloneMultipartFileHeader
func cloneMultipartFileHeader(fh *multipart.FileHeader) *multipart.FileHeader {
	if fh == nil {
		return nil
	}
	fh2 := new(multipart.FileHeader)
	*fh2 = *fh
	fh2.Header = textproto.MIMEHeader(Header(fh.Header).Clone())
	return fh2
}

// cloneOrMakeHeader invokes Header.Clone but if the
// result is nil, it'll instead make and return a non-nil Header.
//
// cloneOrMakeHeader should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/searKing/golang
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname cloneOrMakeHeader
func cloneOrMakeHeader(hdr Header) Header {
	clone := hdr.Clone()
	if clone == nil {
		clone = make(Header)
	}
	return clone
}