aj
e4d64a88eb
PDFsharp/MigraDoc layout and font state is process-wide. Parallel exports of the same snapshot laid text out differently (for example merged words like "Total physicalsheets" and shifted table columns). Serialize the whole render-and-save in NestPdfWriter.Write; reports are rare. Regression test exports one snapshot 128 times in parallel and compares page content streams with a sequential export; it failed with dozens of mismatches per run before the lock.
57 lines
2.3 KiB
C#
57 lines
2.3 KiB
C#
using System.Collections.Concurrent;
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using System.Text;
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using OpenNest.Reporting;
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using PdfSharp.Pdf.IO;
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namespace OpenNest.Tests.Reporting;
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public sealed class NestPdfWriterConcurrencyTests : IDisposable
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{
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private readonly string directory = Path.Combine(Path.GetTempPath(), "opennest-pdf-concurrency-" + Guid.NewGuid().ToString("N"));
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public NestPdfWriterConcurrencyTests() => Directory.CreateDirectory(directory);
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public void Dispose() => Directory.Delete(directory, true);
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[Fact]
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public void Write_ConcurrentExportsProduceTheSameLayoutAsASequentialExport()
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{
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// PDFsharp/MigraDoc layout shares process-wide font state; unsynchronized concurrent
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// exports produced shifted/merged words (for example "Total physicalsheets").
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var snapshot = NestReportBuilder.Capture(NestReportTestData.CreateNest(), NestReportTestData.GeneratedAt);
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var reference = Path.Combine(directory, "reference.pdf");
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NestPdfWriter.Write(snapshot, reference);
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var expected = PageContent(reference);
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var mismatches = new ConcurrentBag<int>();
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Parallel.For(0, 128, new ParallelOptions { MaxDegreeOfParallelism = System.Math.Max(8, Environment.ProcessorCount) }, index =>
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{
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var path = Path.Combine(directory, $"export-{index}.pdf");
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NestPdfWriter.Write(snapshot, path);
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if (PageContent(path) != expected)
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mismatches.Add(index);
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});
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Assert.Empty(mismatches);
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}
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/// <summary>Page content streams only: document IDs and font-subset tags vary per export.</summary>
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private static string PageContent(string path)
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{
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using var pdf = PdfReader.Open(path, PdfDocumentOpenMode.Import);
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var text = new StringBuilder();
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foreach (var page in pdf.Pages)
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{
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foreach (var item in page.Contents.Elements)
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{
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var dictionary = (item as PdfSharp.Pdf.Advanced.PdfReference)?.Value as PdfSharp.Pdf.PdfDictionary
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?? item as PdfSharp.Pdf.PdfDictionary;
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if (dictionary?.Stream != null)
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text.Append(Encoding.Latin1.GetString(dictionary.Stream.UnfilteredValue));
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}
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text.Append('\f');
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}
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return text.ToString();
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}
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}
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