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Replace bad StringReader usage with String.Split() #784

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Merged
merged 5 commits into from
Nov 6, 2018
Merged

Replace bad StringReader usage with String.Split() #784

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0b1f3af
Replace bad StringReader usage with String.Split()
rjmholt Oct 23, 2018
f002a6f
Change some whitespace
rjmholt Oct 24, 2018
705eff5
Reorder string splitting
rjmholt Oct 24, 2018
50c5fb4
Fix test
rjmholt Oct 24, 2018
4429850
Include variant line split tests
Oct 29, 2018
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30 changes: 8 additions & 22 deletions src/PowerShellEditorServices/Workspace/ScriptFile.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,12 @@ public class ScriptFile
{
#region Private Fields

private static readonly string[] s_newlines = new []
{
"\r\n",
"\n"
};

private Token[] scriptTokens;
private Version powerShellVersion;

Expand Down Expand Up @@ -167,8 +173,8 @@ public ScriptFile(
new StringReader(initialBuffer),
powerShellVersion)
{

}

/// <summary>
/// Creates a new ScriptFile instance with the specified filepath.
/// </summary>
Expand All @@ -185,7 +191,6 @@ public ScriptFile(
File.ReadAllText(filePath),
powerShellVersion)
{

}

#endregion
Expand Down Expand Up @@ -215,26 +220,7 @@ internal static List<string> GetLinesInternal(string text)
throw new ArgumentNullException(nameof(text));
}

// ReadLine returns null immediately for empty string, so special case it.
if (text.Length == 0)
{
return new List<string> {string.Empty};
}

using (var reader = new StringReader(text))
{
// 50 is a rough guess for typical average line length, this saves some list
// resizes in the common case and does not hurt meaningfully if we're wrong.
var list = new List<string>(text.Length / 50);
string line;

while ((line = reader.ReadLine()) != null)
{
list.Add(line);
}

return list;
}
return new List<string>(text.Split(s_newlines, StringSplitOptions.None));
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So I take it this splits by \r\n if it finds \r\n and then splits by \n if it just finds \n? Just want to make sure that it doesn't get split by \n if it finds a \r\n

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@rjmholt rjmholt Oct 24, 2018 •
edited
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Oh you raise an excellent point! I need to reorder the array:

To avoid ambiguous results when strings in separator have characters in common, the Split operation proceeds from the beginning to the end of the value of the instance, and matches the first element in separator that is equal to a delimiter in the instance. The order in which substrings are encountered in the instance takes precedence over the order of elements in separator.

}

/// <summary>
Expand Down
55 changes: 35 additions & 20 deletions test/PowerShellEditorServices.Test/Session/ScriptFileTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -255,26 +255,35 @@ private void AssertFileChange(

public class ScriptFileGetLinesTests
{
private ScriptFile scriptFile;
private const string TestString_NoTrailingNewline = "Line One\r\nLine Two\r\nLine Three\r\nLine Four\r\nLine Five";

private const string TestString_TrailingNewline = TestString_NoTrailingNewline + "\r\n";

private static readonly string[] s_newLines = new string[] { "\r\n" };

private static readonly string[] s_testStringLines_noTrailingNewline = TestString_NoTrailingNewline.Split(s_newLines, StringSplitOptions.None);

private static readonly string[] s_testStringLines_trailingNewline = TestString_TrailingNewline.Split(s_newLines, StringSplitOptions.None);

private ScriptFile _scriptFile_trailingNewline;

private ScriptFile _scriptFile_noTrailingNewline;

private const string TestString = "Line One\r\nLine Two\r\nLine Three\r\nLine Four\r\nLine Five";
private readonly string[] TestStringLines =
TestString.Split(
new string[] { "\r\n" },
StringSplitOptions.None);

public ScriptFileGetLinesTests()
{
this.scriptFile =
ScriptFileChangeTests.CreateScriptFile(
"Line One\r\nLine Two\r\nLine Three\r\nLine Four\r\nLine Five\r\n");
_scriptFile_noTrailingNewline = ScriptFileChangeTests.CreateScriptFile(
TestString_NoTrailingNewline);

_scriptFile_trailingNewline = ScriptFileChangeTests.CreateScriptFile(
TestString_TrailingNewline);
}

[Fact]
public void CanGetWholeLine()
{
string[] lines =
this.scriptFile.GetLinesInRange(
_scriptFile_noTrailingNewline.GetLinesInRange(
new BufferRange(5, 1, 5, 10));

Assert.Equal(1, lines.Length);
Expand All @@ -285,17 +294,17 @@ public void CanGetWholeLine()
public void CanGetMultipleWholeLines()
{
string[] lines =
this.scriptFile.GetLinesInRange(
_scriptFile_noTrailingNewline.GetLinesInRange(
new BufferRange(2, 1, 4, 10));

Assert.Equal(TestStringLines.Skip(1).Take(3), lines);
Assert.Equal(s_testStringLines_noTrailingNewline.Skip(1).Take(3), lines);
}

[Fact]
public void CanGetSubstringInSingleLine()
{
string[] lines =
this.scriptFile.GetLinesInRange(
_scriptFile_noTrailingNewline.GetLinesInRange(
new BufferRange(4, 3, 4, 8));

Assert.Equal(1, lines.Length);
Expand All @@ -306,7 +315,7 @@ public void CanGetSubstringInSingleLine()
public void CanGetEmptySubstringRange()
{
string[] lines =
this.scriptFile.GetLinesInRange(
_scriptFile_noTrailingNewline.GetLinesInRange(
new BufferRange(4, 3, 4, 3));

Assert.Equal(1, lines.Length);
Expand All @@ -324,7 +333,7 @@ public void CanGetSubstringInMultipleLines()
};

string[] lines =
this.scriptFile.GetLinesInRange(
_scriptFile_noTrailingNewline.GetLinesInRange(
new BufferRange(2, 6, 4, 9));

Assert.Equal(expectedLines, lines);
Expand All @@ -341,23 +350,29 @@ public void CanGetRangeAtLineBoundaries()
};

string[] lines =
this.scriptFile.GetLinesInRange(
_scriptFile_noTrailingNewline.GetLinesInRange(
new BufferRange(2, 9, 4, 1));

Assert.Equal(expectedLines, lines);
}

[Fact]
public void CanSplitLines()
public void CanSplitLines_NoTrailingNewline()
{
Assert.Equal(s_testStringLines_noTrailingNewline, _scriptFile_noTrailingNewline.FileLines);
}

[Fact]
public void CanSplitLines_TrailingNewline()
{
Assert.Equal(TestStringLines, scriptFile.FileLines);
Assert.Equal(s_testStringLines_trailingNewline, _scriptFile_trailingNewline.FileLines);
}

[Fact]
public void CanGetSameLinesWithUnixLineBreaks()
{
var unixFile = ScriptFileChangeTests.CreateScriptFile(TestString.Replace("\r\n", "\n"));
Assert.Equal(scriptFile.FileLines, unixFile.FileLines);
var unixFile = ScriptFileChangeTests.CreateScriptFile(TestString_NoTrailingNewline.Replace("\r\n", "\n"));
Assert.Equal(_scriptFile_noTrailingNewline.FileLines, unixFile.FileLines);
}

[Fact]
Expand Down