Module: OllamaAgent::Runtime::UnifiedDiffApply

Defined in:
lib/ollama_agent/runtime/unified_diff_apply.rb

Overview

Pure-Ruby application of a unified diff to a single file (no shell). Supports typical git-style hunks; multiple hunks are applied bottom-up.

Defined Under Namespace

Classes: Hunk

Class Method Summary collapse

Class Method Details

.apply(old_content, diff_text) ⇒ :ok, String

rubocop:disable Metrics/MethodLength, Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity – diff engine

Parameters:

  • old_content (String) —

    current file bytes (UTF-8 or binary)

  • diff_text (String) —

    unified diff (may include headers)

Returns:

  • (:ok, String) —

    or [:error, String]



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# File 'lib/ollama_agent/runtime/unified_diff_apply.rb', line 22

def apply(old_content, diff_text)
  hunks = parse_hunks(diff_text.to_s)
  return [:error, "no hunk in patch"] if hunks.empty?

  lines = to_line_array(old_content)
  had_trailing_nl = old_content.end_with?("\n")
  sorted = hunks.sort_by { |hunk| -hunk.old_start }
  sorted.each do |hunk|
    lines = apply_hunk(lines, hunk)
    return [:error, "patch did not apply cleanly"] unless lines
  end

  out = lines.join("\n")
  out += "\n" if had_trailing_nl || !old_content.empty?
  [:ok, out]
end

.apply_hunk(lines, hunk) ⇒ Object 



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# File 'lib/ollama_agent/runtime/unified_diff_apply.rb', line 73

def apply_hunk(lines, hunk)
  work = lines.dup
  idx = hunk.old_start - 1
  return nil if idx.negative?

  hunk.body.each do |raw|
    op = raw[0]
    text = raw[1..]
    case op
    when " "
      return nil unless work[idx] == text

      idx += 1
    when "-"
      return nil unless work[idx] == text

      work.delete_at(idx)
    when "+"
      work.insert(idx, text)
      idx += 1
    else
      return nil
    end
  end
  work
end

.parse_hunks(diff_text) ⇒ Object 



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# File 'lib/ollama_agent/runtime/unified_diff_apply.rb', line 39

def parse_hunks(diff_text)
  raw = diff_text.lines.map(&:chomp)
  hunks = []
  i = 0
  while i < raw.length
    line = raw[i]
    if line.start_with?("@@")
      m = line.match(/@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@/)
      unless m
        i += 1
        next
      end
      old_start = m[1].to_i
      old_count = m[2] ? m[2].to_i : 1
      i += 1
      body = []
      while i < raw.length && !raw[i].start_with?("@@") && !raw[i].start_with?("diff --git")
        l = raw[i]
        i += 1
        next if l.empty?

        first = l[0]
        next if first == "\\"

        body << l if " +-".include?(first)
      end
      hunks << Hunk.new(old_start: old_start, old_count: old_count, body: body)
    else
      i += 1
    end
  end
  hunks
end

.to_line_array(content) ⇒ Object 



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# File 'lib/ollama_agent/runtime/unified_diff_apply.rb', line 12

def to_line_array(content)
  return [] if content.nil? || content.empty?

  content.each_line.map { |l| l.delete_suffix("\n") }
end