Add File.ReadLinesAsync #43108
Add File.ReadLinesAsync #43108
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Note regarding the This serves as a reminder for when your PR is modifying a ref *.cs file and adding/modifying public APIs, to please make sure the API implementation in the src *.cs file is documented with triple slash comments, so the PR reviewers can sign off that change. |
| Debug.Assert(!string.IsNullOrEmpty(path)); | ||
| Debug.Assert(encoding != null); | ||
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| using StreamReader sr = AsyncStreamReader(path, encoding); |
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File.ReadLines has some special behaviors related to this. It actually creates the StreamReader as part of the ReadLines call, so that the file is opened as part of the ReadLines call and any validation as part of that (e.g. does the file exist) happens as part of the call to ReadLines, rather than as part of the first MoveNext on the resulting iterator. It then has to take care to create a new reader on subsequent iterations. For consistency between ReadLines and ReadLinesAsync, and for all the reasons ReadLines chose that approach, we should probably do the same thing here, even though it means extra complication.
| cancellationToken.ThrowIfCancellationRequested(); | ||
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| string? line; | ||
| while ((line = await sr.ReadLineAsync().ConfigureAwait(false)) != null) |
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The lack of cancellation support in ReadLineAsync is unfortunate for this API in particular, as it means the cancellation token won't help unblocking work stuck because no data is available yet (e.g. if reading from a NetworkStream). We should strongly consider implementing #20824 before adding this API that would sit on top of it; otherwise, dev expectations on this ReadLinesAsync API aren't going to be met. cc: @terrajobst, @carlossanlop, @jozkee
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Yeah, that would be nice. I have no problem holding off until #20824 gets in 👍🏻
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Draft Pull Request was automatically closed for inactivity. It can be manually reopened in the next 30 days if the work resumes. |
ghost
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Opening this up for early feedback. Will add XML docs and tests once I get everything set up properly 😅
Closes #2214