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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package source
import (
"fmt"
"go/ast"
"golang.org/x/tools/internal/lsp/snippet"
)
// structFieldSnippets calculates the plain and placeholder snippets for struct literal field names.
func (c *completer) structFieldSnippets(label, detail string) (*snippet.Builder, *snippet.Builder) {
clInfo := c.enclosingCompositeLiteral
if clInfo == nil || !clInfo.isStruct() {
return nil, nil
}
// If we are already in a key-value expression, we don't want a snippet.
if clInfo.kv != nil {
return nil, nil
}
// We don't want snippet unless we are completing a field name. maybeInFieldName
// means we _might_ not be a struct field name, but this method is only called for
// struct fields, so we can ignore that possibility.
if !clInfo.inKey && !clInfo.maybeInFieldName {
return nil, nil
}
plain, placeholder := &snippet.Builder{}, &snippet.Builder{}
label = fmt.Sprintf("%s: ", label)
// A plain snippet turns "Foo{Ba<>" into "Foo{Bar: <>".
plain.WriteText(label)
plain.WritePlaceholder(nil)
// A placeholder snippet turns "Foo{Ba<>" into "Foo{Bar: <*int*>".
placeholder.WriteText(label)
placeholder.WritePlaceholder(func(b *snippet.Builder) {
b.WriteText(detail)
})
// If the cursor position is on a different line from the literal's opening brace,
// we are in a multiline literal.
if c.view.Session().Cache().FileSet().Position(c.pos).Line != c.view.Session().Cache().FileSet().Position(clInfo.cl.Lbrace).Line {
plain.WriteText(",")
placeholder.WriteText(",")
}
return plain, placeholder
}
// functionCallSnippets calculates the plain and placeholder snippets for function calls.
func (c *completer) functionCallSnippets(name string, params []string) (*snippet.Builder, *snippet.Builder) {
// If we are the left side (i.e. "Fun") part of a call expression,
// we don't want a snippet since there are already parens present.
if len(c.path) > 1 {
switch n := c.path[1].(type) {
case *ast.CallExpr:
if n.Fun == c.path[0] {
return nil, nil
}
case *ast.SelectorExpr:
if len(c.path) > 2 {
if call, ok := c.path[2].(*ast.CallExpr); ok && call.Fun == c.path[1] {
return nil, nil
}
}
}
}
plain, placeholder := &snippet.Builder{}, &snippet.Builder{}
label := fmt.Sprintf("%s(", name)
// A plain snippet turns "someFun<>" into "someFunc(<>)".
plain.WriteText(label)
if len(params) > 0 {
plain.WritePlaceholder(nil)
}
plain.WriteText(")")
// A placeholder snippet turns "someFun<>" into "someFunc(<*i int*>, *s string*)".
placeholder.WriteText(label)
for i, p := range params {
if i > 0 {
placeholder.WriteText(", ")
}
placeholder.WritePlaceholder(func(b *snippet.Builder) {
b.WriteText(p)
})
}
placeholder.WriteText(")")
return plain, placeholder
}