history.go

Documentation: edge-infra.dev/pkg/sds/emergencyaccess/emulator

     1  package emulator
     2  
     3  import (
     4  	"bufio"
     5  	"fmt"
     6  	"os"
     7  )
     8  
     9  type commandHistory struct {
    10  	file    *os.File
    11  	history []string
    12  }
    13  
    14  // Create new commandHistory struct.
    15  // Opens specified file and reads its contents into a string array
    16  func newCommandHistory(filepath string) (commandHistory, error) {
    17  	f, err := os.OpenFile(filepath, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
    18  	if err != nil {
    19  		return commandHistory{}, fmt.Errorf("could not open file")
    20  	}
    21  	ch := commandHistory{file: f, history: []string{}}
    22  	err = ch.readFromFile()
    23  	if err != nil {
    24  		return commandHistory{}, fmt.Errorf("error reading from file")
    25  	}
    26  	return ch, nil
    27  }
    28  
    29  func (ch *commandHistory) readFromFile() error {
    30  	scanner := bufio.NewScanner(ch.file)
    31  	for scanner.Scan() {
    32  		ch.history = append(ch.history, scanner.Text())
    33  	}
    34  	return scanner.Err()
    35  }
    36  
    37  // Update both history and file with new input
    38  func (ch *commandHistory) updateHistory(in string, limit int) error {
    39  	if len(ch.history) == 0 || in != ch.history[len(ch.history)-1] {
    40  		ch.history = append(ch.history, in)
    41  		// Truncate ch.history to only the most recent commands within size limit
    42  		if len(ch.history) > limit {
    43  			diff := len(ch.history) - limit
    44  			ch.history = ch.history[diff:]
    45  		}
    46  		// Write new line to file
    47  		_, err := ch.file.WriteString(in + "\n")
    48  		if err != nil {
    49  			return err
    50  		}
    51  	}
    52  	return nil
    53  }
    54  
    55  func (ch *commandHistory) close() {
    56  	ch.file.Close()
    57  }
    58
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