fix highlight problem of git diff

[a1012112796]

related #23176

try fix it with @silverwind solution in #23176 (comment)

looks the result is good. but looks it will cost to much memorry when the file is large. maybe limt the max file size?

[wxiaoguang]

What's algorithm?

The current method supports to highlight deleted/added/changed part, could you show how your algorithm works?

[silverwind]

looks the result is good. but looks it will cost to much memorry when the file is large. maybe limt the max file size?

Hmm yes, full file highlight is expensive. Might need a option for max line count after which to fall back to the cheap method. Kind of similar to git.MAX_GIT_DIFF_LINES but for the whole file, so the value can probably be larger, like start with 2000 or so.

[a1012112796]

What's algorithm?

The current method supports to highlight deleted/added/changed part, could you show how your algorithm works?

no change about algorithm.

but render full file instead of render it line by line. ref: #23176 (comment)

[wxiaoguang]

no change about algorithm.

but render full file instead of render it line by line. ref: #23176 (comment)

I mean , does the old style diff still work? This feature is pretty useful.

[a1012112796]

no change about algorithm.
but render full file instead of render it line by line. ref: #23176 (comment)

I mean , does the old style diff still work? This feature is pretty useful.

Oh, I see. sorry, I forgot it, will fix it later.

[a1012112796]

@wxiaoguang fixed 4362fa6

[wxiaoguang]

Haven't looked into details, some quick thoughts after a quick review:

• why MAX_DIFF_HIGHLIGHT_FILE_SIZE=5k ? models/user/user.go is 37k
• the name of MAX_DIFF_HIGHLIGHT_FILE_SIZE seems unclear, files exceed this limit also get hightlighted (line by line)
• the "HighlightContent" could be dropped?
  • if the content is not highlighted, then highlight it , and set HasHighlightContent = true
• there are too many arguments for diffWithHighlight, the logic doesn't seem easy to understand how these arguments affect each other
• could there be some tests to cover the new logic?

[a1012112796]

I'd like try some refactor to make highlight.File() using io.Reader directly at first. ref:

• proposal: Add TokeniseStream support alecthomas/chroma#791
• a1012112796@93a5d88