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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2020 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package assets
import (
"fmt"
"sort"
"github.com/snapcore/snapd/osutil"
)
var registeredAssets = map[string][]byte{}
// ForEditions wraps a snippet that is used in editions starting with
// FirstEdition.
type ForEditions struct {
// First edition this snippet is used in
FirstEdition uint
// Snippet data
Snippet []byte
}
var registeredEditionSnippets = map[string][]ForEditions{}
// registerInternal registers an internal asset under the given name.
func registerInternal(name string, data []byte) {
if _, ok := registeredAssets[name]; ok {
panic(fmt.Sprintf("asset %q is already registered", name))
}
registeredAssets[name] = data
}
// Internal returns the content of an internal asset registered under the given
// name, or nil when none was found.
func Internal(name string) []byte {
return registeredAssets[name]
}
type byFirstEdition []ForEditions
func (b byFirstEdition) Len() int { return len(b) }
func (b byFirstEdition) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
func (b byFirstEdition) Less(i, j int) bool { return b[i].FirstEdition < b[j].FirstEdition }
func sanitizeSnippets(snippets []ForEditions) error {
if !sort.IsSorted(byFirstEdition(snippets)) {
return fmt.Errorf("snippets must be sorted in ascending edition number order")
}
for i := range snippets {
if i == 0 {
continue
}
if snippets[i-1].FirstEdition == snippets[i].FirstEdition {
return fmt.Errorf(`first edition %v repeated`, snippets[i].FirstEdition)
}
}
return nil
}
// registerSnippetForEditions register a set of snippets, each carrying the
// first edition number it applies to, under a given key.
func registerSnippetForEditions(name string, snippets []ForEditions) {
if _, ok := registeredEditionSnippets[name]; ok {
panic(fmt.Sprintf("edition snippets %q are already registered", name))
}
if err := sanitizeSnippets(snippets); err != nil {
panic(fmt.Errorf("cannot validate snippets %q: %v", name, err))
}
registeredEditionSnippets[name] = snippets
}
// SnippetForEdition returns a snippet registered under given name,
// applicable for the provided edition number.
func SnippetForEdition(name string, edition uint) []byte {
snippets := registeredEditionSnippets[name]
if snippets == nil {
return nil
}
var current []byte
// snippets are sorted by ascending edition number when adding
for _, snip := range snippets {
if edition >= snip.FirstEdition {
current = snip.Snippet
} else {
break
}
}
return current
}
// MockInternal mocks the contents of an internal asset for use in testing.
func MockInternal(name string, data []byte) (restore func()) {
osutil.MustBeTestBinary("mocking can be done only in tests")
old, ok := registeredAssets[name]
registeredAssets[name] = data
return func() {
if ok {
registeredAssets[name] = old
} else {
delete(registeredAssets, name)
}
}
}
// MockSnippetsForEdition mocks the contents of per-edition snippets.
func MockSnippetsForEdition(name string, snippets []ForEditions) (restore func()) {
osutil.MustBeTestBinary("mocking can be done only in tests")
old, ok := registeredEditionSnippets[name]
snippetsCopy := make([]ForEditions, len(snippets))
copy(snippetsCopy, snippets)
if ok {
delete(registeredEditionSnippets, name)
}
registerSnippetForEditions(name, snippetsCopy)
return func() {
if ok {
registeredEditionSnippets[name] = old
} else {
delete(registeredAssets, name)
}
}
}
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