[API Proposal]: TextEncoder.FindFirstCharacterToEncode(ReadOnlySpan<char>)

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#114,423 3 comments 1 reaction 0 assignees View on GitHub

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp
Domain
api, backend-api-design

Research direction

Start at the TextEncoder entry point and compare the existing unsafe UTF-16 overload with the safe UTF-8 overload. Trace the System.Text.Json usage referenced in the issue and the linked pull request. Done means the proposed ReadOnlySpan API is available and the unnecessary unsafe usage can be removed.

Written by the indexing model from the issue text.

Description

api-suggestion area-System.Text.Encodings.Web reduce-unsafe
Background and motivation

TextEncoder does not provide a safe version of FindFirstCharacterToEncode for UTF16, it only has an unsafe (accepting an unmanaged pointer) for UTF16 and a safe one for UTF8.

It's needed to remove an unnecessary unsafe context from System.Text.Json, see https://github.com/dotnet/runtime/pull/114154/files#r2025039597

This is part of the "remove unsafe" effort.

API Proposal
namespaceSystem.Text.Encodings.Web;

public abstract class TextEncoder
{
        public abstract unsafe int FindFirstCharacterToEncode(char* text, int textLength);
+       public int FindFirstCharacterToEncode(ReadOnlySpan<char> text);
        public virtual int FindFirstCharacterToEncodeUtf8(ReadOnlySpan<byte> utf8Text)
}
API Usage
return (encoder ?? JavaScriptEncoder.Default).FindFirstCharacterToEncode(value);

instead of what we currently have to do:

unsafe
{
    fixed (char* ptr = value)
    {
        return (encoder ?? JavaScriptEncoder.Default).FindFirstCharacterToEncode(ptr, value.Length);
    }
}
Alternative Designs

No response

Risks

No response

Dominant language
C#
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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

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