Rewrote data parsing using streams.
This commit is contained in:
parent
42afc67d46
commit
4ee7ec2127
6 changed files with 273 additions and 223 deletions
211
lib/dcat.dart
211
lib/dcat.dart
|
|
@ -8,19 +8,31 @@ library dcat;
|
|||
import 'dart:convert';
|
||||
import 'dart:io';
|
||||
|
||||
/// Failure exit code.
|
||||
const exitFailure = 1;
|
||||
|
||||
/// Success exit code.
|
||||
const exitSuccess = 0;
|
||||
|
||||
const _lineFeed = 10;
|
||||
|
||||
/// Holds the [cat] result [exitCode] and error [messages].
|
||||
class CatResult {
|
||||
/// The exit code.
|
||||
int exitCode = exitSuccess;
|
||||
|
||||
/// The error messages.
|
||||
final List<String> messages = [];
|
||||
|
||||
CatResult();
|
||||
|
||||
/// Add a message.
|
||||
/// Returns `true` if the [exitCode] is [exitFailure].
|
||||
bool get isFailure => exitCode == exitFailure;
|
||||
|
||||
/// Returns `true` if the [exitCode] is [exitSuccess].
|
||||
bool get isSuccess => exitCode == exitSuccess;
|
||||
|
||||
/// Add a message with an optional path.
|
||||
void addMessage(int exitCode, String message, {String? path}) {
|
||||
this.exitCode = exitCode;
|
||||
if (path != null && path.isNotEmpty) {
|
||||
|
|
@ -31,40 +43,35 @@ class CatResult {
|
|||
}
|
||||
}
|
||||
|
||||
/// Concatenates files in [paths] to [stdout] or [File].
|
||||
// Holds the current line number and last character.
|
||||
class _LastLine {
|
||||
int lineNumber;
|
||||
int lastChar;
|
||||
|
||||
_LastLine(this.lineNumber, this.lastChar);
|
||||
}
|
||||
|
||||
/// Concatenates files in [paths] to the standard output or a file.
|
||||
///
|
||||
/// * [output] should be an [IOSink] like [stdout] or a [File].
|
||||
/// * [output] should be an [IOSink] such as [stdout] or [File.openWrite].
|
||||
/// * [input] can be [stdin].
|
||||
/// * [log] is used for debugging/testing purposes.
|
||||
///
|
||||
/// The remaining optional parameters are similar to the [GNU cat utility](https://www.gnu.org/software/coreutils/manual/html_node/cat-invocation.html#cat-invocation).
|
||||
Future<CatResult> cat(List<String> paths, Object output,
|
||||
Future<CatResult> cat(List<String> paths, IOSink output,
|
||||
{Stream<List<int>>? input,
|
||||
List<String>? log,
|
||||
bool showEnds = false,
|
||||
bool numberNonBlank = false,
|
||||
bool showLineNumbers = false,
|
||||
bool showTabs = false,
|
||||
bool squeezeBlank = false,
|
||||
bool showNonPrinting = false}) async {
|
||||
var result = CatResult();
|
||||
var lineNumber = 1;
|
||||
log?.clear();
|
||||
final result = CatResult();
|
||||
final lastLine = _LastLine(0, _lineFeed);
|
||||
if (paths.isEmpty) {
|
||||
if (input != null) {
|
||||
final lines = await _readStream(input);
|
||||
try {
|
||||
await _writeLines(
|
||||
lines,
|
||||
lineNumber,
|
||||
output,
|
||||
log,
|
||||
showEnds,
|
||||
showLineNumbers,
|
||||
numberNonBlank,
|
||||
showTabs,
|
||||
squeezeBlank,
|
||||
showNonPrinting);
|
||||
await _writeStream(input, lastLine, output, showEnds, showLineNumbers,
|
||||
numberNonBlank, showTabs, squeezeBlank, showNonPrinting);
|
||||
} catch (e) {
|
||||
result.addMessage(exitFailure, '$e');
|
||||
}
|
||||
|
|
@ -72,25 +79,14 @@ Future<CatResult> cat(List<String> paths, Object output,
|
|||
} else {
|
||||
for (final path in paths) {
|
||||
try {
|
||||
final Stream<String> lines;
|
||||
final Stream<List<int>> stream;
|
||||
if (path == '-' && input != null) {
|
||||
lines = await _readStream(input);
|
||||
stream = input;
|
||||
} else {
|
||||
lines = utf8.decoder
|
||||
.bind(File(path).openRead())
|
||||
.transform(const LineSplitter());
|
||||
stream = File(path).openRead();
|
||||
}
|
||||
lineNumber = await _writeLines(
|
||||
lines,
|
||||
lineNumber,
|
||||
output,
|
||||
log,
|
||||
showEnds,
|
||||
showLineNumbers,
|
||||
numberNonBlank,
|
||||
showTabs,
|
||||
squeezeBlank,
|
||||
showNonPrinting);
|
||||
await _writeStream(stream, lastLine, output, showEnds, showLineNumbers,
|
||||
numberNonBlank, showTabs, squeezeBlank, showNonPrinting);
|
||||
} on FileSystemException catch (e) {
|
||||
final String? osMessage = e.osError?.message;
|
||||
final String message;
|
||||
|
|
@ -111,80 +107,77 @@ Future<CatResult> cat(List<String> paths, Object output,
|
|||
return result;
|
||||
}
|
||||
|
||||
/// Parses line with non-printing characters.
|
||||
Future<String> _parseNonPrinting(String line, bool showTabs) async {
|
||||
// Writes parsed data from a stream
|
||||
Future<void> _writeStream(
|
||||
Stream stream,
|
||||
_LastLine lastLine,
|
||||
IOSink out,
|
||||
bool showEnds,
|
||||
bool showLineNumbers,
|
||||
bool numberNonBlank,
|
||||
bool showTabs,
|
||||
bool squeezeBlank,
|
||||
bool showNonPrinting) async {
|
||||
const tab = 9;
|
||||
int squeeze = 0;
|
||||
final sb = StringBuffer();
|
||||
for (var ch in line.runes) {
|
||||
if (ch >= 32) {
|
||||
if (ch < 127) {
|
||||
sb.writeCharCode(ch);
|
||||
} else if (ch == 127) {
|
||||
sb.write('^?');
|
||||
} else {
|
||||
sb.write('U+' + ch.toRadixString(16).padLeft(4, '0').toUpperCase());
|
||||
}
|
||||
} else if (ch == 9 && !showTabs) {
|
||||
sb.write('\t');
|
||||
} else {
|
||||
sb
|
||||
..write('^')
|
||||
..writeCharCode(ch + 64);
|
||||
}
|
||||
}
|
||||
return sb.toString();
|
||||
}
|
||||
|
||||
/// Reads from stream (stdin, etc.)
|
||||
Future<Stream<String>> _readStream(Stream<List<int>> input) async =>
|
||||
input.transform(utf8.decoder).transform(const LineSplitter());
|
||||
|
||||
/// Writes lines to stdout.
|
||||
Future<int> _writeLines(Stream<String> lines, int lineNumber, Object out,
|
||||
[List<String>? log,
|
||||
bool showEnds = false,
|
||||
bool showLineNumbers = false,
|
||||
bool showNonBlank = false,
|
||||
bool showTabs = false,
|
||||
bool squeezeBlank = false,
|
||||
bool showNonPrinting = false]) async {
|
||||
var emptyLine = 0;
|
||||
final sb = StringBuffer();
|
||||
await for (final line in lines) {
|
||||
await stream.forEach((data) {
|
||||
sb.clear();
|
||||
if (squeezeBlank && line.isEmpty) {
|
||||
if (++emptyLine >= 2) {
|
||||
continue;
|
||||
for (final ch in utf8.decode(data).runes) {
|
||||
if (lastLine.lastChar == _lineFeed) {
|
||||
if (squeezeBlank) {
|
||||
if (ch == _lineFeed) {
|
||||
if (squeeze >= 1) {
|
||||
lastLine.lastChar = ch;
|
||||
continue;
|
||||
}
|
||||
squeeze++;
|
||||
} else {
|
||||
squeeze = 0;
|
||||
}
|
||||
}
|
||||
if (showLineNumbers || numberNonBlank) {
|
||||
if (!numberNonBlank || ch != _lineFeed) {
|
||||
sb.write('${++lastLine.lineNumber}'.padLeft(6) + '\t');
|
||||
}
|
||||
}
|
||||
}
|
||||
} else {
|
||||
emptyLine = 0;
|
||||
}
|
||||
if (showLineNumbers || (showNonBlank && line.isNotEmpty)) {
|
||||
sb.write('${lineNumber++} '.padLeft(8));
|
||||
}
|
||||
|
||||
if (showNonPrinting) {
|
||||
sb.write(await _parseNonPrinting(line, showTabs));
|
||||
} else if (showTabs) {
|
||||
sb.write(line.replaceAll('\t', '^I'));
|
||||
} else {
|
||||
sb.write(line);
|
||||
}
|
||||
|
||||
if (showEnds) {
|
||||
sb.write('\$');
|
||||
}
|
||||
|
||||
log?.add(sb.toString());
|
||||
|
||||
try {
|
||||
if (out is IOSink) {
|
||||
out.writeln(sb);
|
||||
} else if (out is File) {
|
||||
await out.writeAsString("$sb\n", mode: FileMode.append);
|
||||
lastLine.lastChar = ch;
|
||||
if (ch == _lineFeed) {
|
||||
if (showEnds) {
|
||||
sb.write('\$');
|
||||
}
|
||||
} else if (ch == tab) {
|
||||
if (showTabs) {
|
||||
sb.write('^I');
|
||||
continue;
|
||||
}
|
||||
} else if (showNonPrinting) {
|
||||
if (ch >= 32) {
|
||||
if (ch < 127) {
|
||||
// ASCII
|
||||
sb.writeCharCode(ch);
|
||||
continue;
|
||||
} else if (ch == 127) {
|
||||
// NULL
|
||||
sb.write('^?');
|
||||
continue;
|
||||
} else {
|
||||
// UNICODE
|
||||
sb.write('U+' + ch.toRadixString(16).padLeft(4, '0').toUpperCase());
|
||||
continue;
|
||||
}
|
||||
} else {
|
||||
sb
|
||||
..write('^')
|
||||
..writeCharCode(ch + 64);
|
||||
continue;
|
||||
}
|
||||
}
|
||||
} catch (e) {
|
||||
rethrow;
|
||||
sb.writeCharCode(ch);
|
||||
}
|
||||
}
|
||||
return lineNumber;
|
||||
}
|
||||
if (sb.isNotEmpty) {
|
||||
out.write(sb);
|
||||
}
|
||||
});
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue