如何确定Git是否将文件处理为二进制文件或文本？ [英] How to determine if Git handles a file as binary or as text?

问题描述

我知道GIT以某种方式自动检测文件是二进制文件还是文本文件，并且如果需要，可以使用gitattributes手动设置。但是，还有一种方法可以问GIT如何处理文件吗？

然后，假设我有一个包含两个文件的GIT存储库：a ascii。包含纯文本和包含随机二进制内容的 binary.dat 文件。 Git将第一个dat文件处理为文本，将第二个文件处理为二进制文件。现在我想写一个GIT webfrontend，它有一个文本文件查看器和一个二进制文件的特殊查看器（例如显示一个十六进制转储文件）。当然，我可以实现自己的文本/二进制检查，但如果观众依赖GIT处理这些文件的信息，它会更有用。

所以我该如何问GIT是否将文件视为文本或二进制文件？ 解决方案

builtin_diff() ¹ 调用 diff_filespec_is_binary（） ，它调用 buffer_is_binary（） ，它检查一个零字节（NUL字符）在前8000个字节（或整个长度，如果更短）。

我没有看到这个是二进制吗？测试是明确暴露的在任何命令中都可以使用。

git merge-file 直接使用 buffer_is_binary / code>，所以你可以使用它：

  git merge-file / dev / null / dev / null文件测试
  

它似乎会产生错误消息，如 error：无法合并二进制文件：file-to-test ，并在给定二进制文件时产生退出状态255。虽然我不确定我是否会依赖这种行为。

也许 git diff --numstat 会是更可靠：

  isBinary（）{
p = $（printf'％s\t-\t' - ）
t = $（git diff --no-index --numstat / dev / null$ 1）
 case$ tin$ p*）return 0 ;; esac 
 return 1 
} 
是二进制文件测试&&回声二进制|| echo二进制
  

对于二进制文件， - numstat 输出应该以 - TAB - TAB开头，所以我们只是测试一下。

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<1>
builtin_diff（） has字符串像二进制文件％s和％s不同应该很熟悉。

I know that GIT somehow automatically detects if a file is binary or text and that gitattributes can be used to set this manually if needed. But is there also a way to ask GIT how it treats a file?

So let's say I have a GIT repository with two files in it: A ascii.dat file containing plain-text and a binary.dat file containing random binary stuff. Git handles the first dat file as text and the secondary file as binary. Now I want to write a GIT webfrontend which has a viewer for text files and a special viewer for binary files (Displaying a Hex dump for example). Sure, I could implement my own text/binary check but it would be more useful if the viewer relies on the information how GIT handles these files.

So how can I ask GIT if it treats a file as text or binary?

解决方案

builtin_diff()¹ calls diff_filespec_is_binary() which calls buffer_is_binary() which checks for any occurrence of a zero byte (NUL "character") in the first 8000 bytes (or the entire length if shorter).

I do not see that this "is it binary?" test is explicitly exposed in any command though.

git merge-file directly uses buffer_is_binary(), so you may be able to make use of it:

git merge-file /dev/null /dev/null file-to-test

It seems to produce the error message like error: Cannot merge binary files: file-to-test and yields an exit status of 255 when given a binary file. I am not sure I would want to rely on this behavior though.

Maybe git diff --numstat would be more reliable:

isBinary() {
    p=$(printf '%s\t-\t' -)
    t=$(git diff --no-index --numstat /dev/null "$1")
    case "$t" in "$p"*) return 0 ;; esac
    return 1
}
isBinary file-to-test && echo binary || echo not binary

For binary files, the --numstat output should start with - TAB - TAB, so we just test for that.

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¹ builtin_diff() has strings like Binary files %s and %s differ that should be familiar.

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