94 lines
2.5 KiB
Go
94 lines
2.5 KiB
Go
package addrs
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import (
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"fmt"
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"github.com/hashicorp/hcl/v2"
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)
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// Reference describes a reference to an address with source location
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// information.
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type Reference struct {
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Subject Referenceable
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SourceRange hcl.Range
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Remaining hcl.Traversal
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}
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// ParseRef attempts to extract a referencable address from the prefix of the
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// given traversal, which must be an absolute traversal or this function
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// will panic.
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//
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// If no error diagnostics are returned, the returned reference includes the
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// address that was extracted, the source range it was extracted from, and any
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// remaining relative traversal that was not consumed as part of the
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// reference.
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//
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// If error diagnostics are returned then the Reference value is invalid and
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// must not be used.
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func ParseRef(traversal hcl.Traversal) (*Reference, hcl.Diagnostics) {
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ref, diags := parseRef(traversal)
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// Normalize a little to make life easier for callers.
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if ref != nil {
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if len(ref.Remaining) == 0 {
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ref.Remaining = nil
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}
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}
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return ref, diags
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}
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func parseRef(traversal hcl.Traversal) (*Reference, hcl.Diagnostics) {
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var diags hcl.Diagnostics
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root := traversal.RootName()
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rootRange := traversal[0].SourceRange()
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switch root {
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case "var":
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name, rng, remain, diags := parseSingleAttrRef(traversal)
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return &Reference{
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Subject: InputVariable{Name: name},
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SourceRange: rng,
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Remaining: remain,
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}, diags
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default:
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diags = append(diags, &hcl.Diagnostic{
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Severity: hcl.DiagError,
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Summary: "Unhandled reference type",
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Detail: `Currently parseRef can only parse "var" references.`,
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Subject: &rootRange,
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})
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}
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return nil, diags
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}
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func parseSingleAttrRef(traversal hcl.Traversal) (string, hcl.Range, hcl.Traversal, hcl.Diagnostics) {
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var diags hcl.Diagnostics
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root := traversal.RootName()
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rootRange := traversal[0].SourceRange()
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if len(traversal) < 2 {
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diags = append(diags, &hcl.Diagnostic{
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Severity: hcl.DiagError,
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Summary: "Invalid reference",
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Detail: fmt.Sprintf("The %q object cannot be accessed directly. Instead, access one of its attributes.", root),
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Subject: &rootRange,
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})
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return "", hcl.Range{}, nil, diags
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}
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if attrTrav, ok := traversal[1].(hcl.TraverseAttr); ok {
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return attrTrav.Name, hcl.RangeBetween(rootRange, attrTrav.SrcRange), traversal[2:], diags
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}
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diags = diags.Append(&hcl.Diagnostic{
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Severity: hcl.DiagError,
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Summary: "Invalid reference",
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Detail: fmt.Sprintf("The %q object does not support this operation.", root),
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Subject: traversal[1].SourceRange().Ptr(),
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})
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return "", hcl.Range{}, nil, diags
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}
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