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generate.go
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generate.go
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// DO NOT CHANGE PACKAGE
// Package template provides a template used by copygen to generate custom code.
package template
import (
"strings"
"github.com/reedom/copygen/cli/models"
)
// Generate generates code.
// GENERATOR FUNCTION.
// EDITABLE.
// DO NOT REMOVE.
func Generate(gen *models.Generator) (string, error) {
var content strings.Builder
content.WriteString(string(gen.Keep) + "\n")
for i := range gen.Functions {
content.WriteString(Function(&gen.Functions[i]) + "\n")
}
return content.String(), nil
}
// Function provides generated code for a function.
func Function(function *models.Function) string {
var fn strings.Builder
fn.WriteString(generateComment(function) + "\n")
fn.WriteString(generateSignature(function) + "\n")
fn.WriteString(generateFuncCall(function, function.Options.PreProcess, false))
fn.WriteString(generateBody(function))
fn.WriteString(generateFuncCall(function, function.Options.PostProcess, true))
fn.WriteString(generateReturn(function))
return fn.String()
}
// generateComment generates a function comment.
func generateComment(function *models.Function) string {
var toComment strings.Builder
for i, toType := range function.To {
if i+1 == len(function.To) {
toComment.WriteString(toType.Name())
break
}
toComment.WriteString(toType.Name() + ", ")
}
var fromComment strings.Builder
for i, fromType := range function.From {
if i+1 == len(function.From) {
fromComment.WriteString(fromType.Name())
break
}
fromComment.WriteString(fromType.Name() + ", ")
}
return "// " + function.Name + " copies a " + fromComment.String() + " to a " + toComment.String() + "."
}
// generateSignature generates a function's signature.
func generateSignature(function *models.Function) string {
ret := ""
if function.Options.Error {
ret = "(err error)"
}
return "func " + function.Name + "(" + generateParameters(function) + ")" + ret + "{"
}
// generateParameters generates the parameters of a function.
func generateParameters(function *models.Function) string {
var parameters strings.Builder
for _, toType := range function.To {
parameters.WriteString(toType.Field.VariableName + " " + toType.Name() + ", ")
}
for i, fromType := range function.From {
if i+1 == len(function.From) {
parameters.WriteString(fromType.Field.VariableName + " " + fromType.Name())
break
}
parameters.WriteString(fromType.Field.VariableName + " " + fromType.Name() + ", ")
}
return parameters.String()
}
// generateBody generates the body of a function.
func generateBody(function *models.Function) string {
var body strings.Builder
// Assign fields to ToType(s).
for i, toType := range function.To {
body.WriteString(generateAssignment(toType))
if i+1 != len(function.To) {
body.WriteString("\n")
}
}
return body.String()
}
// generateAssignment generates assignments for a to-type.
func generateAssignment(toType models.Type) string {
var assign strings.Builder
assign.WriteString("// " + toType.Name() + " fields\n")
for _, toField := range toType.Field.AllFields(nil, nil) {
if toField.From != nil {
fromField := toField.From
errVal := ""
if fromField.Options.Convert.Error {
errVal = ", err"
}
assign.WriteString(toField.FullVariableName("") + errVal + " = ")
if !fromField.Options.Convert.IsEmpty() {
assign.WriteString(fromField.Options.Convert.Ident + "(" + fromField.FullVariableName("") + ")\n")
if fromField.Options.Convert.Error {
assign.WriteString("if err != nil {\nreturn\n}\n")
}
} else {
switch {
case toField.FullDefinition() == fromField.FullDefinition():
assign.WriteString(fromField.FullVariableName("") + "\n")
case toField.FullDefinition()[1:] == fromField.FullDefinition():
assign.WriteString("&" + fromField.FullVariableName("") + "\n")
case toField.FullDefinition() == fromField.FullDefinition()[1:]:
assign.WriteString("*" + fromField.FullVariableName("") + "\n")
}
}
}
}
return assign.String()
}
// generatePreprocess may generate a function call.
func generateFuncCall(function *models.Function, ident string, last bool) string {
if ident == "" {
return ""
}
var builder strings.Builder
if function.Options.Error {
builder.WriteString("err = ")
}
builder.WriteString(ident)
builder.WriteString("(")
builder.WriteString(generateFuncCallParameters(function))
builder.WriteString(")\n")
if !last && function.Options.Error {
builder.WriteString("if err != nil {\nreturn\n}\n")
}
return builder.String()
}
// generateFuncCallParameters generates the parameters of a function.
func generateFuncCallParameters(function *models.Function) string {
var parameters strings.Builder
for _, toType := range function.To {
parameters.WriteString(toType.Field.VariableName)
parameters.WriteString(", ")
}
for i, fromType := range function.From {
parameters.WriteString(fromType.Field.VariableName)
if i < len(function.From)-1 {
parameters.WriteString(", ")
}
}
return parameters.String()
}
// generateReturn generates a return statement for the function.
func generateReturn(function *models.Function) string {
if function.Options.Error {
return "\nreturn\n}"
}
return "}"
}