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Fix correctness and perf issues across the lookup and extraction paths #221

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Merged
SimonCropp merged 1 commit into from
Jul 5, 2026
Merged

Fix correctness and perf issues across the lookup and extraction paths #221

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96 changes: 65 additions & 31 deletions src/EmptyFiles/AllFiles.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -38,15 +38,15 @@ static AllFiles()
sheets = AddCategory(sheetExtensions, Category.Sheet);
slides = AddCategory(slideExtensions, Category.Slide);
binary = AddCategory(binaryExtensions, Category.Binary);
var all = new Dictionary<string, EmptyFile>();
var all = new Dictionary<string, EmptyFile>(StringComparer.OrdinalIgnoreCase);
Append(archives);
Append(documents);
Append(images);
Append(sheets);
Append(slides);
Append(binary);

files = all.ToFrozenDictionary();
files = all.ToFrozenDictionary(StringComparer.OrdinalIgnoreCase);

void Append(FrozenDictionary<string, EmptyFile> files)
{
Expand All @@ -59,7 +59,7 @@ void Append(FrozenDictionary<string, EmptyFile> files)

static FrozenDictionary<string, EmptyFile> AddCategory(FrozenSet<string> extensions, Category category)
{
Dictionary<string, EmptyFile> items = [];
Dictionary<string, EmptyFile> items = new(StringComparer.OrdinalIgnoreCase);
var categoryName = category
.ToString()
.ToLowerInvariant();
Expand All @@ -69,47 +69,58 @@ static FrozenDictionary<string, EmptyFile> AddCategory(FrozenSet<string> extensi
items[extension] = EmptyFile.Embedded(category, extension, resourceName);
}

return items.ToFrozenDictionary();
return items.ToFrozenDictionary(StringComparer.OrdinalIgnoreCase);
}

static readonly Lazy<string> extractDirectory = new(
() =>
{
// AssemblyVersion and FileVersion are both pinned (1.0.0), so use the
// informational version, which tracks the package version, to keep
// extracted templates isolated per release. Strip any "+sha" suffix
// appended by source control integration.
var assembly = typeof(AllFiles).Assembly;
var version = assembly.GetName().Version?.ToString() ?? "unknown";
var informational = assembly
.GetCustomAttribute<AssemblyInformationalVersionAttribute>()
?.InformationalVersion;
var version = "unknown";
if (informational != null)
{
var plusIndex = informational.IndexOf('+');
version = plusIndex == -1 ? informational : informational[..plusIndex];
}

return Path.Combine(Path.GetTempPath(), "EmptyFiles", version);
});

internal static string ExtractDirectory => extractDirectory.Value;

static void ExtractAll(string directory)
{
var assembly = typeof(AllFiles).Assembly;
ExtractCategory(assembly, directory, "archive", archiveExtensions);
ExtractCategory(assembly, directory, "binary", binaryExtensions);
ExtractCategory(assembly, directory, "document", documentExtensions);
ExtractCategory(assembly, directory, "image", imageExtensions);
ExtractCategory(assembly, directory, "sheet", sheetExtensions);
ExtractCategory(assembly, directory, "slide", slideExtensions);
ExtractCategory(directory, "archive", archives);
ExtractCategory(directory, "binary", binary);
ExtractCategory(directory, "document", documents);
ExtractCategory(directory, "image", images);
ExtractCategory(directory, "sheet", sheets);
ExtractCategory(directory, "slide", slides);
}

static void ExtractCategory(Assembly assembly, string root, string categoryName, FrozenSet<string> extensions)
static void ExtractCategory(string root, string categoryName, FrozenDictionary<string, EmptyFile> items)
{
var categoryDirectory = Path.Combine(root, categoryName);
Directory.CreateDirectory(categoryDirectory);
foreach (var extension in extensions)
foreach (var emptyFile in items.Values)
{
var resourceName = $"EmptyFiles.{categoryName}.empty{extension}";
using var resource = assembly.GetManifestResourceStream(resourceName) ??
throw new($"Embedded resource not found: {resourceName}");
var target = Path.Combine(categoryDirectory, $"empty{extension}");
if (File.Exists(target) && new FileInfo(target).Length == resource.Length)
using var resource = emptyFile.OpenRead();
var target = Path.Combine(categoryDirectory, $"empty{emptyFile.Extension}");
if (File.Exists(target) &&
new FileInfo(target).Length == resource.Length)
{
continue;
}

using var file = File.Create(target);
resource.CopyTo(file);
using var fileStream = File.Create(target);
resource.CopyTo(fileStream);
}
}

Expand Down Expand Up @@ -149,21 +160,27 @@ public static void UseFile(Category category, string file)
throw new($"Unknown category: {category}");
}

var mergedFiles = new Dictionary<string, EmptyFile>(files, StringComparer.OrdinalIgnoreCase)
{
[extension] = emptyFile
};
files = mergedFiles.ToFrozenDictionary(StringComparer.OrdinalIgnoreCase);

void Init(ref FrozenDictionary<string, EmptyFile> emptyFiles, ref FrozenSet<string> extensions)
{
var tempDictionary = new Dictionary<string, EmptyFile>();
var tempDictionary = new Dictionary<string, EmptyFile>(StringComparer.OrdinalIgnoreCase);
foreach (var (key, value) in emptyFiles)
{
tempDictionary[key] = value;
}

tempDictionary[extension] = emptyFile;
emptyFiles = tempDictionary.ToFrozenDictionary();
var tempSet = new HashSet<string>(extensions)
emptyFiles = tempDictionary.ToFrozenDictionary(StringComparer.OrdinalIgnoreCase);
var tempSet = new HashSet<string>(extensions, StringComparer.OrdinalIgnoreCase)
{
extension
};
extensions = tempSet.ToFrozenSet();
extensions = tempSet.ToFrozenSet(StringComparer.OrdinalIgnoreCase);
}
}

Expand All @@ -189,7 +206,8 @@ void Init(ref FrozenDictionary<string, EmptyFile> emptyFiles, ref FrozenSet<stri
".tar",
".xz",
".zip"
]);
],
StringComparer.OrdinalIgnoreCase);

public static IEnumerable<string> DocumentPaths => documents.Values.Select(_ => _.Path);

Expand All @@ -201,7 +219,8 @@ void Init(ref FrozenDictionary<string, EmptyFile> emptyFiles, ref FrozenSet<stri
".odt",
".pdf",
".rtf"
]);
],
StringComparer.OrdinalIgnoreCase);

public static IEnumerable<string> ImagePaths => images.Values.Select(_ => _.Path);

Expand Down Expand Up @@ -239,7 +258,8 @@ void Init(ref FrozenDictionary<string, EmptyFile> emptyFiles, ref FrozenSet<stri
".wdp",
".webp",
".wmp"
]);
],
StringComparer.OrdinalIgnoreCase);

public static IEnumerable<string> SheetPaths => sheets.Values.Select(_ => _.Path);

Expand All @@ -249,7 +269,8 @@ void Init(ref FrozenDictionary<string, EmptyFile> emptyFiles, ref FrozenSet<stri
[
".ods",
".xlsx"
]);
],
StringComparer.OrdinalIgnoreCase);

public static IEnumerable<string> SlidePaths => slides.Values.Select(_ => _.Path);

Expand All @@ -259,7 +280,8 @@ void Init(ref FrozenDictionary<string, EmptyFile> emptyFiles, ref FrozenSet<stri
[
".odp",
".pptx"
]);
],
StringComparer.OrdinalIgnoreCase);

public static IEnumerable<string> BinaryPaths => binary.Values.Select(_ => _.Path);

Expand All @@ -268,7 +290,8 @@ void Init(ref FrozenDictionary<string, EmptyFile> emptyFiles, ref FrozenSet<stri
static FrozenSet<string> binaryExtensions = FrozenSet.ToFrozenSet(
[
".bin"
]);
],
StringComparer.OrdinalIgnoreCase);

public static bool IsEmptyFile(string path)
{
Expand Down Expand Up @@ -319,6 +342,11 @@ public static bool TryCreateFile(string path, bool useEmptyStringForTextFiles =
Guard.AgainstNullOrEmpty(path);
var extension = Path.GetExtension(path);

if (extension.Length == 0)
{
return false;
}

if (useEmptyStringForTextFiles &&
FileExtensions.IsTextExtension(extension))
{
Expand Down Expand Up @@ -351,6 +379,12 @@ static void TryCreateDirectory(string path)

public static bool TryGetPathFor(string extension, [NotNullWhen(true)] out string? path)
{
if (extension.Length > 0 &&
extension[0] != '.')
{
extension = $".{extension}";
}

if (files.TryGetValue(extension, out var emptyFile))
{
path = emptyFile.Path;
Expand Down
2 changes: 1 addition & 1 deletion src/EmptyFiles/ContentTypes.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -235,7 +235,7 @@ public static bool TryGetExtension(string? mediaType, [NotNullWhen(true)] out st
"image/bmp", "bmp"
},
{
"image/heic", ".heic"
"image/heic", "heic"
},
{
"image/heic-sequence", "heics"
Expand Down
49 changes: 43 additions & 6 deletions src/EmptyFiles/EmptyFile.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ public DateTime LastWriteTime
string? path;
DateTime lastWriteTime;
bool extracted;
readonly bool embedded;
readonly object sync = new();

internal static EmptyFile Embedded(Category category, string extension, string resourceName) =>
Expand All @@ -37,6 +38,7 @@ internal static EmptyFile Embedded(Category category, string extension, string r
Category = category;
Extension = extension;
ResourceName = resourceName;
embedded = true;
}

public EmptyFile(string path, in DateTime lastWriteTime, in Category category)
Expand Down Expand Up @@ -68,13 +70,11 @@ void EnsureExtracted()
var directory = System.IO.Path.Combine(AllFiles.ExtractDirectory, categoryName);
Directory.CreateDirectory(directory);
var target = System.IO.Path.Combine(directory, $"empty{Extension}");
var assembly = typeof(EmptyFile).Assembly;
using var resource = assembly.GetManifestResourceStream(ResourceName) ??
throw new($"Embedded resource not found: {ResourceName}");
if (!File.Exists(target) || new FileInfo(target).Length != resource.Length)
using var resource = OpenRead();
if (!File.Exists(target) ||
new FileInfo(target).Length != resource.Length)
{
using var fileStream = File.Create(target);
resource.CopyTo(fileStream);
ExtractTo(directory, target, resource);
}

path = target;
Expand All @@ -83,8 +83,45 @@ void EnsureExtracted()
}
}

// Extract via a unique temp file then move into place, so that parallel
// test processes sharing the temp directory cannot observe or write a
// partially written file. A concurrent process winning the race is treated
// as success, since every process writes byte-identical content.
static void ExtractTo(string directory, string target, Stream resource)
{
var temp = System.IO.Path.Combine(directory, $"{Guid.NewGuid():N}.tmp");
try
{
using (var fileStream = File.Create(temp))
{
resource.CopyTo(fileStream);
}

try
{
File.Move(temp, target);
}
catch (IOException) when (File.Exists(target))
{
// Another process published the file first.
}
}
finally
{
if (File.Exists(temp))
{
File.Delete(temp);
}
}
}

public Stream OpenRead()
{
if (!embedded)
{
return File.OpenRead(Path);
}

var assembly = typeof(EmptyFile).Assembly;
return assembly.GetManifestResourceStream(ResourceName) ??
throw new($"Embedded resource not found: {ResourceName}");
Expand Down
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