refactor verifiable matcher btd to explicitly use file reader for reading file

Summary:
previously.. json::read_file_lines_parallel implictely reads and decompress the file. This wasn't very obvious (2 of us missed this)

We just want to refactor so it's clear that BTD already takes care of decompressing file before calling json decoder.

Differential Revision: D90789486

fbshipit-source-id: 33cbb06b5edaff0a11bc7b9d62de23688f27205b

Author: Martin Hsueh

td_util/src/json.rs

@@ -89,6 +89,18 @@ pub fn read_file_lines_par_iter<T: for<'a> Deserialize<'a> + Send>(
     Ok(rdr.lines().par_bridge().map(parse_line::<T>))
 }
 
+/// Read JSON lines from a reader. The order of entries is not guaranteed.
+/// Use this when you want explicit control over file opening (e.g., with file_io::file_reader).
+pub fn read_reader_lines_parallel<T: for<'a> Deserialize<'a> + Send>(
+    reader: impl BufRead + Send,
+) -> anyhow::Result<Vec<T>> {
+    reader
+        .lines()
+        .par_bridge()
+        .map(parse_line::<T>)
+        .collect::<anyhow::Result<Vec<T>>>()
+}
+
 /// Read a file that consists of many JSON blobs, one per line.
 pub fn read_file_lines<T: for<'a> Deserialize<'a>>(filename: &Path) -> anyhow::Result<Vec<T>> {
     fn f<T: for<'a> Deserialize<'a>>(filename: &Path) -> anyhow::Result<Vec<T>> {