/*
** 2016 February 26
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C# code to perform regular expression replacements
** using the standard input and output channels.
*/
using System;
using System.Diagnostics;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;
///////////////////////////////////////////////////////////////////////////////
#region Assembly Metadata
[assembly: AssemblyTitle("Replace Tool")]
[assembly: AssemblyDescription("Replace text using standard input/output.")]
[assembly: AssemblyCompany("SQLite Development Team")]
[assembly: AssemblyProduct("SQLite")]
[assembly: AssemblyCopyright("Public Domain")]
[assembly: ComVisible(false)]
[assembly: Guid("95a0513f-8863-48cd-a76f-cb80868cb578")]
[assembly: AssemblyVersion("1.0.*")]
#if DEBUG
[assembly: AssemblyConfiguration("Debug")]
#else
[assembly: AssemblyConfiguration("Release")]
#endif
#endregion
///////////////////////////////////////////////////////////////////////////////
namespace Replace
{
/// <summary>
/// This enumeration is used to represent all the possible exit codes from
/// this tool.
/// </summary>
internal enum ExitCode
{
/// <summary>
/// The file download was a success.
/// </summary>
Success = 0,
/// <summary>
/// The command line arguments are missing (i.e. null). Generally,
/// this should not happen.
/// </summary>
MissingArgs = 1,
/// <summary>
/// The wrong number of command line arguments was supplied.
/// </summary>
WrongNumArgs = 2,
/// <summary>
/// The "matchingOnly" flag could not be converted to a value of the
/// <see cref="Boolean"/> type.
/// </summary>
BadMatchingOnlyFlag = 3,
/// <summary>
/// An exception was caught in <see cref="Main" />. Generally, this
/// should not happen.
/// </summary>
Exception = 4
}
///////////////////////////////////////////////////////////////////////////
internal static class Replace
{
#region Private Support Methods
/// <summary>
/// This method displays an error message to the console and/or
/// displays the command line usage information for this tool.
/// </summary>
/// <param name="message">
/// The error message to display, if any.
/// </param>
/// <param name="usage">
/// Non-zero to display the command line usage information.
/// </param>
private static void Error(
string message,
bool usage
)
{
if (message != null)
Console.WriteLine(message);
string fileName = Path.GetFileName(
Process.GetCurrentProcess().MainModule.FileName);
Console.WriteLine(String.Format(
"usage: {0} <regExPattern> <regExSubSpec> <matchingOnly>",
fileName));
}
#endregion
///////////////////////////////////////////////////////////////////////
#region Program Entry Point
/// <summary>
/// This is the entry-point for this tool. It handles processing the
/// command line arguments, reading from the standard input channel,
/// replacing any matching lines of text, and writing to the standard
/// output channel.
/// </summary>
/// <param name="args">
/// The command line arguments.
/// </param>
/// <returns>
/// Zero upon success; non-zero on failure. This will be one of the
/// values from the <see cref="ExitCode" /> enumeration.
/// </returns>
private static int Main(
string[] args
)
{
//
// NOTE: Sanity check the command line arguments.
//
if (args == null)
{
Error(null, true);
return (int)ExitCode.MissingArgs;
}
if (args.Length != 3)
{
Error(null, true);
return (int)ExitCode.WrongNumArgs;
}
try
{
//
// NOTE: Create a regular expression from the first command
// line argument. Then, grab the replacement string,
// which is the second argument.
//
Regex regEx = new Regex(args[0]);
string replacement = args[1];
//
// NOTE: Attempt to convert the third argument to a boolean.
//
bool matchingOnly;
if (!bool.TryParse(args[2], out matchingOnly))
{
Error(null, true);
return (int)ExitCode.BadMatchingOnlyFlag;
}
//
// NOTE: Grab the standard input and output channels from the
// console.
//
TextReader inputTextReader = Console.In;
TextWriter outputTextWriter = Console.Out;
//
// NOTE: Loop until end-of-file is hit on the standard input
// stream.
//
while (true)
{
//
// NOTE: Read a line from the standard input channel. If
// null is returned here, there is no more input and
// we are done.
//
string inputLine = inputTextReader.ReadLine();
if (inputLine == null)
break;
//
// NOTE: Perform regular expression replacements on this
// line, if any. Then, write the modified line to
// the standard output channel.
//
string outputLine = regEx.Replace(inputLine, replacement);
if (!matchingOnly || !String.Equals(
inputLine, outputLine, StringComparison.Ordinal))
{
outputTextWriter.WriteLine(outputLine);
}
}
//
// NOTE: At this point, everything has succeeded.
//
return (int)ExitCode.Success;
}
catch (Exception e)
{
//
// NOTE: An exception was caught. Report it via the console
// and return failure.
//
Error(e.ToString(), false);
return (int)ExitCode.Exception;
}
}
#endregion
}
}