mirror of https://github.com/pulumi/pulumi.git
74 lines
2.2 KiB
Go
74 lines
2.2 KiB
Go
// Copyright 2016-2017, Pulumi Corporation. All rights reserved.
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package tools
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import (
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"bufio"
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"bytes"
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"fmt"
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"os"
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"github.com/pulumi/pulumi/pkg/util/contract"
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)
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// GenWriter adds some convenient helpers atop a buffered writer.
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type GenWriter struct {
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tool string // the name of the code-generator.
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f *os.File // the file being written to.
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buff *bytes.Buffer // the buffer (if there is no file).
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w *bufio.Writer // the buffered writer used to emit code.
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}
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func NewGenWriter(tool string, file string) (*GenWriter, error) {
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// If the file is non-empty, open up a writer and overwrite whatever file contents already exist.
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if file != "" {
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f, err := os.OpenFile(file, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
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if err != nil {
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return nil, err
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}
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return &GenWriter{tool: tool, f: f, w: bufio.NewWriter(f)}, nil
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}
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// Otherwise, we are emitting into an in-memory buffer.
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var buff bytes.Buffer
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return &GenWriter{tool: tool, buff: &buff, w: bufio.NewWriter(&buff)}, nil
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}
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// Flush explicitly flushes the writer's pending writes.
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func (g *GenWriter) Flush() error {
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return g.w.Flush()
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}
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// Close flushes and closes the underlying writer.
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func (g *GenWriter) Close() error {
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err := g.w.Flush()
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contract.IgnoreError(err)
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if g.f != nil {
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return g.f.Close()
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}
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return nil
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}
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// Writefmt wraps the bufio.Writer.WriteString function, but also performs fmt.Sprintf-style formatting.
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func (g *GenWriter) Writefmt(msg string, args ...interface{}) {
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_, err := g.w.WriteString(fmt.Sprintf(msg, args...))
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contract.IgnoreError(err)
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}
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// Writefmtln wraps the bufio.Writer.WriteString function, performing fmt.Sprintf-style formatting and appending \n.
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func (g *GenWriter) Writefmtln(msg string, args ...interface{}) {
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g.Writefmt(msg+"\n", args...)
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}
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// EmitHeaderWarning emits the standard "WARNING" into a generated file.
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func (g *GenWriter) EmitHeaderWarning() {
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g.Writefmtln("// *** WARNING: this file was generated by %v. ***", g.tool)
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g.Writefmtln("// *** Do not edit by hand unless you're certain you know what you are doing! ***")
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g.Writefmtln("")
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}
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// Buffer returns whatever has been written to the in-memory buffer (in non-file cases).
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func (g *GenWriter) Buffer() string {
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return g.buff.String()
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}
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