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/******************************************************************************
*
* Copyright 2018 Stefan Majewsky <majewsky@gmx.net>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
package schwift
import (
"fmt"
"reflect"
"github.com/majewsky/schwift/headers"
)
//AccountHeaders contains the headers for an account. The Headers attribute
//contains the actual set of headers that was returned from a HEAD or GET
//request on the account, and will be sent by a PUT or POST request. The other
//attributes allow type-safe access to well-known headers, as noted in the tags
//next to each field.
//
//Follow the link on the Headers attribute for the documentation of the Get(),
//Set(), Del(), Clear() methods on this type.
type AccountHeaders struct {
headers.Headers
BytesUsed headers.Uint64Readonly `schwift:"X-Account-Bytes-Used"`
ContainerCount headers.Uint64Readonly `schwift:"X-Account-Container-Count"`
Metadata headers.Metadata `schwift:"X-Account-Meta-"`
ObjectCount headers.Uint64Readonly `schwift:"X-Account-Object-Count"`
QuotaBytes headers.Uint64 `schwift:"X-Account-Meta-Quota-Bytes"`
TempURLKey headers.String `schwift:"X-Account-Meta-Temp-URL-Key"`
TempURLKey2 headers.String `schwift:"X-Account-Meta-Temp-URL-Key-2"`
Timestamp headers.UnixTimeReadonly `schwift:"X-Timestamp"`
//forbid initialization as struct literal (must use NewAccountHeaders)
initialized bool
}
//NewAccountHeaders prepares a new AccountHeaders instance.
//
//WARNING: Always use this function to construct AccountHeaders instances.
//Failure to do so will result in uncontrolled crashes!
func NewAccountHeaders() AccountHeaders {
var ah AccountHeaders
ah.Headers = make(headers.Headers)
initializeByReflection(&ah)
ah.initialized = true
return ah
}
//Validate returns headers.MalformedHeaderError if the value of any well-known
//header does not conform to its data type. This is called automatically by
//Schwift when preparing an AccountHeaders instance from a GET/HEAD response,
//so you usually do not need to do it yourself. You will get the validation error
//from the Account method doing the request, e.g. Headers() or List().
func (ah AccountHeaders) Validate() error {
return validateByReflection(&ah)
}
//ContainerHeaders contains the headers for a container. The Headers attribute
//contains the actual set of headers that was returned from a HEAD or GET
//request on the container, and will be sent by a PUT or POST request. The
//other attributes allow type-safe access to well-known headers, as noted in
//the tags next to each field.
//
//Follow the link on the Headers attribute for the documentation of the Get(),
//Set(), Del(), Clear() methods on this type.
type ContainerHeaders struct {
headers.Headers
BytesUsed headers.Uint64Readonly `schwift:"X-Container-Bytes-Used"`
BytesUsedQuota headers.Uint64 `schwift:"X-Container-Meta-Quota-Bytes"`
HistoryLocation headers.String `schwift:"X-History-Location"`
Metadata headers.Metadata `schwift:"X-Container-Meta-"`
ObjectCount headers.Uint64Readonly `schwift:"X-Container-Object-Count"`
ObjectCountQuota headers.Uint64 `schwift:"X-Container-Meta-Quota-Count"`
ReadACL headers.String `schwift:"X-Container-Read"`
//StoragePolicy can only be set in a PUT request.
StoragePolicy headers.String `schwift:"X-Storage-Policy"`
SyncKey headers.String `schwift:"X-Container-Sync-Key"`
SyncTo headers.String `schwift:"X-Container-Sync-To"`
TempURLKey2 headers.String `schwift:"X-Container-Meta-Temp-URL-Key-2"`
TempURLKey headers.String `schwift:"X-Container-Meta-Temp-URL-Key"`
Timestamp headers.UnixTimeReadonly `schwift:"X-Timestamp"`
VersionsLocation headers.String `schwift:"X-Versions-Location"`
WriteACL headers.String `schwift:"X-Container-Write"`
//TODO map X-Container-Meta-Access-Control-* (requires new data types)
//forbid initialization as struct literal (must use NewContainerHeaders)
initialized bool
}
//NewContainerHeaders prepares a new ContainerHeaders instance.
//
//WARNING: Always use this function to construct ContainerHeaders instances.
//Failure to do so will result in uncontrolled crashes!
func NewContainerHeaders() ContainerHeaders {
var ch ContainerHeaders
ch.Headers = make(headers.Headers)
initializeByReflection(&ch)
ch.initialized = true
return ch
}
//Validate returns headers.MalformedHeaderError if the value of any well-known
//header does not conform to its data type. This is called automatically by
//Schwift when preparing an ContainerHeaders instance from a GET/HEAD response,
//so you usually do not need to do it yourself. You will get the validation error
//from the Container method doing the request, e.g. Headers() or List().
func (ch ContainerHeaders) Validate() error {
return validateByReflection(&ch)
}
type fieldInfo struct {
FieldName string
HeaderName string
}
func initializeByReflection(value interface{}) {
rv := reflect.ValueOf(value).Elem()
hdrs := rv.FieldByName("Headers").Interface().(headers.Headers)
foreachTaggedField(value, func(fieldPtr interface{}, info fieldInfo) error {
base := reflect.ValueOf(fieldPtr).Elem().FieldByName("Base").Addr().Interface().(*headers.Base)
base.H = hdrs
base.K = info.HeaderName
return nil
})
}
type validator interface {
Validate() error
}
func validateByReflection(value interface{}) error {
return foreachTaggedField(value, func(fieldPtr interface{}, info fieldInfo) error {
if validator, ok := fieldPtr.(validator); ok {
err := validator.Validate()
if err != nil {
return err
}
}
return nil
})
}
func ensureInitializedByReflection(value interface{}) {
initialized := reflect.ValueOf(value).FieldByName("initialized").Bool()
if !initialized {
msg := "values of type %T MUST be initialized with the corresponding New...() function"
panic(fmt.Sprintf(msg, value, value))
}
}
func foreachTaggedField(value interface{}, callback func(fieldPtr interface{}, info fieldInfo) error) error {
rv := reflect.ValueOf(value).Elem()
//iterate over the struct fields
for idx := 0; idx < rv.NumField(); idx++ {
fieldType := rv.Type().Field(idx)
headerName := fieldType.Tag.Get("schwift")
if headerName != "" {
fieldPtr := rv.Field(idx).Addr().Interface()
err := callback(fieldPtr, fieldInfo{
FieldName: fieldType.Name,
HeaderName: headerName,
})
if err != nil {
return err
}
}
}
return nil
}
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