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| 1 | +// Copyright 2020 VMware, Inc. |
| 2 | +// SPDX-License-Identifier: BSD-2-Clause |
| 3 | + |
| 4 | +package lensed |
| 5 | + |
| 6 | +import ( |
| 7 | + "encoding/json" |
| 8 | + "fmt" |
| 9 | + "io" |
| 10 | + "strconv" |
| 11 | + "strings" |
| 12 | + |
| 13 | + "github.com/go-openapi/jsonpointer" |
| 14 | + "github.com/google/go-jsonnet" |
| 15 | + "github.com/google/go-jsonnet/ast" |
| 16 | + "github.com/vmware-labs/go-yaml-edit/splice" |
| 17 | + "golang.org/x/text/transform" |
| 18 | +) |
| 19 | + |
| 20 | +// Jsonnet implements the "jsonnet" lens. |
| 21 | +// |
| 22 | +// The jsonnet lens implementation is still in its early stages, it only supports: |
| 23 | +// 1. double quoted string scalars |
| 24 | +// 2. single level ~{"foo":"bar", "baz":"quz"} matchers |
| 25 | +type Jsonnet struct{} |
| 26 | + |
| 27 | +// Apply implements the Lens interface. |
| 28 | +func (Jsonnet) Apply(src []byte, vals []Setter) ([]byte, error) { |
| 29 | + var ops []splice.Op |
| 30 | + |
| 31 | + root, err := jsonnet.SnippetToAST("-", string(src)) |
| 32 | + if err != nil { |
| 33 | + return nil, err |
| 34 | + } |
| 35 | + |
| 36 | + for _, v := range vals { |
| 37 | + p, err := jsonpointer.New(v.Pointer) |
| 38 | + if err != nil { |
| 39 | + return nil, err |
| 40 | + } |
| 41 | + path := p.DecodedTokens() |
| 42 | + |
| 43 | + n, err := findJsonnetNode(root, path) |
| 44 | + if err != nil { |
| 45 | + return nil, err |
| 46 | + } |
| 47 | + start, err := lineColToPos(src, n.Loc().Begin.Line, n.Loc().Begin.Column+1) |
| 48 | + if err != nil { |
| 49 | + return nil, err |
| 50 | + } |
| 51 | + end, err := lineColToPos(src, n.Loc().End.Line, n.Loc().End.Column+1) |
| 52 | + if err != nil { |
| 53 | + return nil, err |
| 54 | + } |
| 55 | + |
| 56 | + var oldval []byte |
| 57 | + switch n := n.(type) { |
| 58 | + case *ast.LiteralString: |
| 59 | + oldval = []byte(n.Value) |
| 60 | + default: |
| 61 | + return nil, fmt.Errorf("unhandled node type %T", n) |
| 62 | + } |
| 63 | + |
| 64 | + newval, err := v.Value.Transform(oldval) |
| 65 | + if err != nil { |
| 66 | + return nil, err |
| 67 | + } |
| 68 | + |
| 69 | + ops = append(ops, splice.Span(start, end).With(fmt.Sprintf("%q", string(newval)))) |
| 70 | + } |
| 71 | + b, _, err := transform.Bytes(splice.T(ops...), src) |
| 72 | + return b, err |
| 73 | +} |
| 74 | + |
| 75 | +func findJsonnetNode(root ast.Node, path []string) (ast.Node, error) { |
| 76 | + if len(path) == 0 { |
| 77 | + return root, nil |
| 78 | + } |
| 79 | + p := path[0] |
| 80 | + |
| 81 | + switch n := root.(type) { |
| 82 | + case *ast.DesugaredObject: |
| 83 | + for _, f := range n.Fields { |
| 84 | + if k, ok := f.Name.(*ast.LiteralString); !ok { |
| 85 | + continue |
| 86 | + } else if p == k.Value { |
| 87 | + return findJsonnetNode(f.Body, path[1:]) |
| 88 | + } |
| 89 | + } |
| 90 | + case *ast.Array: |
| 91 | + var exprs []ast.Node |
| 92 | + for _, e := range n.Elements { |
| 93 | + exprs = append(exprs, e.Expr) |
| 94 | + } |
| 95 | + |
| 96 | + e, err := matchJsonnetArrayItem(p, exprs) |
| 97 | + if err != nil { |
| 98 | + return nil, err |
| 99 | + } |
| 100 | + return findJsonnetNode(e, path[1:]) |
| 101 | + case *ast.Local: |
| 102 | + return findJsonnetNode(n.Body, path) |
| 103 | + default: |
| 104 | + return nil, fmt.Errorf("unsupported jsonnet node type: %T", n) |
| 105 | + } |
| 106 | + |
| 107 | + return nil, fmt.Errorf("cannot find field %q in object", p) |
| 108 | +} |
| 109 | + |
| 110 | +func lineColToPos(src []byte, line, column int) (int, error) { |
| 111 | + l, c := 1, 1 |
| 112 | + for i, r := range string(src) { |
| 113 | + c++ |
| 114 | + if r == '\n' { |
| 115 | + l++ |
| 116 | + c = 1 |
| 117 | + } |
| 118 | + if l == line && c == column { |
| 119 | + return i, nil |
| 120 | + } |
| 121 | + } |
| 122 | + return 0, io.EOF |
| 123 | +} |
| 124 | + |
| 125 | +func matchJsonnetArrayItem(p string, exprs []ast.Node) (ast.Node, error) { |
| 126 | + if strings.HasPrefix(p, "~{") { |
| 127 | + var m map[string]string |
| 128 | + if err := json.Unmarshal([]byte(p[1:]), &m); err != nil { |
| 129 | + return nil, err |
| 130 | + } |
| 131 | + nodes, err := filterJsonnetArrayItems(exprs, isTreeSubsetPred(m)) |
| 132 | + if err != nil { |
| 133 | + return nil, err |
| 134 | + } |
| 135 | + if got, want := len(nodes), 1; got != want { |
| 136 | + return nil, fmt.Errorf("bad number of subtree matches: got=%d, want=%d", got, want) |
| 137 | + } |
| 138 | + return nodes[0], nil |
| 139 | + } |
| 140 | + i, err := strconv.Atoi(p) |
| 141 | + if err != nil { |
| 142 | + return nil, err |
| 143 | + } |
| 144 | + return exprs[i], nil |
| 145 | +} |
| 146 | + |
| 147 | +type jsonnetNodePredicate func(ast.Node) bool |
| 148 | + |
| 149 | +func isTreeSubsetPred(a map[string]string) jsonnetNodePredicate { |
| 150 | + return func(b ast.Node) bool { |
| 151 | + return isTreeSubset(a, b) |
| 152 | + } |
| 153 | +} |
| 154 | + |
| 155 | +func isTreeSubset(a map[string]string, b ast.Node) bool { |
| 156 | + for k, v := range a { |
| 157 | + if !jsonnetObjectHasField(b, k, v) { |
| 158 | + return false |
| 159 | + } |
| 160 | + } |
| 161 | + return true |
| 162 | +} |
| 163 | + |
| 164 | +func jsonnetObjectHasField(b ast.Node, name, value string) bool { |
| 165 | + if o, ok := b.(*ast.DesugaredObject); ok { |
| 166 | + for _, f := range o.Fields { |
| 167 | + if n, ok := f.Name.(*ast.LiteralString); ok && n.Value == name { |
| 168 | + v, ok := f.Body.(*ast.LiteralString) |
| 169 | + return ok && v.Value == value |
| 170 | + } |
| 171 | + } |
| 172 | + } |
| 173 | + return false |
| 174 | +} |
| 175 | + |
| 176 | +func filterJsonnetArrayItems(nodes []ast.Node, pred jsonnetNodePredicate) ([]ast.Node, error) { |
| 177 | + var res []ast.Node |
| 178 | + for _, n := range nodes { |
| 179 | + if pred(n) { |
| 180 | + res = append(res, n) |
| 181 | + } |
| 182 | + } |
| 183 | + return res, nil |
| 184 | +} |
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