mirror of https://github.com/mum4k/termdash.git
87 lines
2.2 KiB
Go
87 lines
2.2 KiB
Go
// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package container
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import (
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"errors"
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"fmt"
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)
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// traversal.go provides functions that navigate the container tree.
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// rootCont returns the root container.
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func rootCont(c *Container) *Container {
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for p := c.parent; p != nil; p = c.parent {
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c = p
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}
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return c
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}
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// visitFunc is executed during traversals when node is visited.
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// If the visit function returns an error, the traversal terminates and the
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// errStr is set to the text of the returned error.
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type visitFunc func(*Container) error
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// preOrder performs pre-order DFS traversal on the container tree.
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func preOrder(c *Container, errStr *string, visit visitFunc) {
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if c == nil || *errStr != "" {
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return
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}
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if err := visit(c); err != nil {
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*errStr = err.Error()
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return
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}
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preOrder(c.first, errStr, visit)
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preOrder(c.second, errStr, visit)
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}
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// postOrder performs post-order DFS traversal on the container tree.
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func postOrder(c *Container, errStr *string, visit visitFunc) {
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if c == nil || *errStr != "" {
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return
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}
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postOrder(c.first, errStr, visit)
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postOrder(c.second, errStr, visit)
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if err := visit(c); err != nil {
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*errStr = err.Error()
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return
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}
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}
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// findID finds container with the provided ID.
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// Returns an error of there is no container with the specified ID.
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func findID(root *Container, id string) (*Container, error) {
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if id == "" {
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return nil, errors.New("the container ID must not be empty")
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}
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var (
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errStr string
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cont *Container
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)
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preOrder(root, &errStr, visitFunc(func(c *Container) error {
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if c.opts.id == id {
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cont = c
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}
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return nil
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}))
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if cont == nil {
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return nil, fmt.Errorf("cannot find container with ID %q", id)
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}
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return cont, nil
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}
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