88 lines
2.3 KiB
Go
88 lines
2.3 KiB
Go
package main
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import (
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"bytes"
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"io"
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"os/exec"
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"strings"
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)
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// Jobs are the way plugins can run processes in the background
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// A job is simply a process that gets executed asynchronously
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// There are callbacks for when the job exits, when the job creates stdout
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// and when the job creates stderr
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// These jobs run in a separate goroutine but the lua callbacks need to be
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// executed in the main thread (where the Lua VM is running) so they are
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// put into the jobs channel which gets read by the main loop
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// JobFunction is a representation of a job (this data structure is what is loaded
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// into the jobs channel)
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type JobFunction struct {
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function func(string, ...string)
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output string
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args []string
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}
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// A CallbackFile is the data structure that makes it possible to catch stderr and stdout write events
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type CallbackFile struct {
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io.Writer
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callback func(string, ...string)
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args []string
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}
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func (f *CallbackFile) Write(data []byte) (int, error) {
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// This is either stderr or stdout
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// In either case we create a new job function callback and put it in the jobs channel
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jobFunc := JobFunction{f.callback, string(data), f.args}
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jobs <- jobFunc
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return f.Writer.Write(data)
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}
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// JobStart starts a process in the background with the given callbacks
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// It returns an *exec.Cmd as the job id
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func JobStart(cmd string, onStdout, onStderr, onExit string, userargs ...string) *exec.Cmd {
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split := strings.Split(cmd, " ")
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args := split[1:]
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cmdName := split[0]
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// Set up everything correctly if the functions have been provided
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proc := exec.Command(cmdName, args...)
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var outbuf bytes.Buffer
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if onStdout != "" {
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proc.Stdout = &CallbackFile{&outbuf, LuaFunctionJob(onStdout), userargs}
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} else {
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proc.Stdout = &outbuf
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}
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if onStderr != "" {
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proc.Stderr = &CallbackFile{&outbuf, LuaFunctionJob(onStderr), userargs}
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} else {
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proc.Stderr = &outbuf
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}
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go func() {
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// Run the process in the background and create the onExit callback
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proc.Run()
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jobFunc := JobFunction{LuaFunctionJob(onExit), string(outbuf.Bytes()), userargs}
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jobs <- jobFunc
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}()
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return proc
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}
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// JobStop kills a job
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func JobStop(cmd *exec.Cmd) {
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cmd.Process.Kill()
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}
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// JobSend sends the given data into the job's stdin stream
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func JobSend(cmd *exec.Cmd, data string) {
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stdin, err := cmd.StdinPipe()
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if err != nil {
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return
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}
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stdin.Write([]byte(data))
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}
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