解决C＃CodeDom导致堆溢出（CS1647）在csc.exe中的解决方法？ [英] Work-around for C# CodeDom causing stack-overflow (CS1647) in csc.exe?

问题描述

我有一种情况，我需要生成一个大的字符串const的类。在我控制之外的代码使我生成的CodeDom树被发送到C＃源，然后编译为更大的Assembly的一部分。

I've got a situation where I need to generate a class with a large string const. Code outside of my control causes my generated CodeDom tree to be emitted to C# source and then later compiled as part of a larger Assembly.

不幸的是，我遇到了一个如果这个字符串的长度在Win2K8 x64（926240在Win2K3 x86）超过335440字符，C＃编译器退出与一个致命错误：

Unfortunately, I've run into a situation whereby if the length of this string exceeds 335440 chars in Win2K8 x64 (926240 in Win2K3 x86), the C# compiler exits with a fatal error:

致命错误CS1647：表达式太长或太复杂，无法在'int' '

MSDN说CS1647是编译器中的堆栈溢出。更仔细地看，我确定CodeDom很好包装我的字符串常量在80字符。这导致编译器连接超过4193字符串块，这显然是C＃编译器在x64 NetFx的堆栈深度。 CSC.exe必须在内部递归计算这个表达式，以恢复我的单个字符串。

MSDN says CS1647 is "a stack overflow in the compiler" (no pun intended!). Looking more closely I've determined that the CodeDom "nicely" wraps my string const at 80 chars.This causes the compiler to concatenate over 4193 string chunks which apparently is the stack depth of the C# compiler in x64 NetFx. CSC.exe must internally recursively evaluate this expression to "rehydrate" my single string.

我的初始问题是：有人知道一个工作更改代码生成器如何发出字符串？我无法控制外部系统使用C＃源作为中间体，而我想这是一个常量（而不是字符串的运行时连接）。

My initial question is this: "does anyone know of a work-around to change how the code generator emits strings?" I cannot control the fact that the external system uses C# source as an intermediate and I want this to be a constant (rather than a runtime concatenation of strings).

或者，如何制定此表达式，以便在一定数量的字符后，我仍然能够创建一个常量，但它由多个大

完全重现在这里：

// this string breaks CSC: 335440 is Win2K8 x64 max, 926240 is Win2K3 x86 max
string HugeString = new String('X', 926300);

CodeDomProvider provider = CodeDomProvider.CreateProvider("C#");
CodeCompileUnit code = new CodeCompileUnit();

// namespace Foo {}
CodeNamespace ns = new CodeNamespace("Foo");
code.Namespaces.Add(ns);

// public class Bar {}
CodeTypeDeclaration type = new CodeTypeDeclaration();
type.IsClass = true;
type.Name = "Bar";
type.Attributes = MemberAttributes.Public;
ns.Types.Add(type);

// public const string HugeString = "XXXX...";

CodeMemberField field = new CodeMemberField();
field.Name = "HugeString";
field.Type = new CodeTypeReference(typeof(String));
field.Attributes = MemberAttributes.Public|MemberAttributes.Const;
field.InitExpression = new CodePrimitiveExpression(HugeString);
type.Members.Add(field);

// generate class file
using (TextWriter writer = File.CreateText("FooBar.cs"))
{
    provider.GenerateCodeFromCompileUnit(code, writer, new CodeGeneratorOptions());
}

// compile class file
CompilerResults results = provider.CompileAssemblyFromFile(new CompilerParameters(), "FooBar.cs");

// output reults
foreach (string msg in results.Output)
{
    Console.WriteLine(msg);
}

// output errors
foreach (CompilerError error in results.Errors)
{
    Console.WriteLine(error);
}

推荐答案

使用CodeSnippetExpression和引用的字符串，我能够发出我想从Microsoft.CSharp.CSharpCodeGenerator看到的源码。

Using a CodeSnippetExpression and a manually quoted string, I was able to emit the source that I would have liked to have seen from Microsoft.CSharp.CSharpCodeGenerator.

因此，为了回答上面的问题，替换这行：

So to answer the question above, replace this line:

field.InitExpression = new CodePrimitiveExpression(HugeString);

：

field.InitExpression = new CodeSnippetExpression(QuoteSnippetStringCStyle(HugeString));

最后修改引用Microsoft.CSharp.CSharpCodeGenerator.QuoteSnippetStringCStyle方法的私有字符串，不包含80个字符：

And finally modify the private string quoting Microsoft.CSharp.CSharpCodeGenerator.QuoteSnippetStringCStyle method to not wrap after 80 chars:

private static string QuoteSnippetStringCStyle(string value)
{
    // CS1647: An expression is too long or complex to compile near '...'
    // happens if number of line wraps is too many (335440 is max for x64, 926240 is max for x86)

    // CS1034: Compiler limit exceeded: Line cannot exceed 16777214 characters
    // theoretically every character could be escaped unicode (6 chars), plus quotes, etc.

    const int LineWrapWidth = (16777214/6) - 4;
    StringBuilder b = new StringBuilder(value.Length+5);

    b.Append("\r\n\"");
    for (int i=0; i<value.Length; i++)
    {
        switch (value[i])
        {
            case '\u2028':
            case '\u2029':
            {
                int ch = (int)value[i];
                b.Append(@"\u");
                b.Append(ch.ToString("X4", CultureInfo.InvariantCulture));
                break;
            }
            case '\\':
            {
                b.Append(@"\\");
                break;
            }
            case '\'':
            {
                b.Append(@"\'");
                break;
            }
            case '\t':
            {
                b.Append(@"\t");
                break;
            }
            case '\n':
            {
                b.Append(@"\n");
                break;
            }
            case '\r':
            {
                b.Append(@"\r");
                break;
            }
            case '"':
            {
                b.Append("\\\"");
                break;
            }
            case '\0':
            {
                b.Append(@"\0");
                break;
            }
            default:
            {
                b.Append(value[i]);
                break;
            }
        }

        if ((i > 0) && ((i % LineWrapWidth) == 0))
        {
            if ((Char.IsHighSurrogate(value[i]) && (i < (value.Length - 1))) && Char.IsLowSurrogate(value[i + 1]))
            {
                b.Append(value[++i]);
            }
            b.Append("\"+\r\n");
            b.Append('"');
        }
    }
    b.Append("\"");
    return b.ToString();
}

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