Problem

At Meta, data pipelines often need to scan very large log exports from systems such as Scribe without reading the entire file into memory. Implement a streaming parser that processes a text file chunk-by-chunk and computes line-level statistics.

Given a file path file_path and an integer chunk_size, write a function that reads the file incrementally and returns:

1. the total number of lines,
2. the number of non-empty lines, and
3. the length of the longest line.

Your solution must not call read() on the full file and must work correctly even when a line is split across multiple chunks.

Formal Specification

• Input:
  • file_path: string path to a UTF-8 text file
  • chunk_size: positive integer number of bytes/characters to read per iteration
• Output:
  • A list [total_lines, non_empty_lines, longest_line_length]

Examples

Example 1 Input: `file contents = "alpha beta

gamma ", chunk_size = 5Output:[4, 3, 5]` Explanation: There are 4 lines total, 3 are non-empty, and the longest line has length 5.

Example 2 Input: file contents = "one very long line without newline", chunk_size = 4 Output: [1, 1, 34] Explanation: The file has one line even without a trailing newline.

Constraints

• 1 <= chunk_size <= 10^6
• File size may be much larger than available memory
• File may or may not end with a newline
• Empty lines must be counted as lines