Make the indexer support gzipped CSV as input

Cargo.lock

@@ -445,9 +445,9 @@ checksum = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
 
 [[package]]
 name = "flate2"
-version = "1.0.16"
+version = "1.0.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "68c90b0fc46cf89d227cc78b40e494ff81287a92dd07631e5af0d06fe3cf885e"
+checksum = "766d0e77a2c1502169d4a93ff3b8c15a71fd946cd0126309752104e5f3c46d94"
 dependencies = [
  "cfg-if",
  "crc32fast",
@@ -1006,6 +1006,7 @@ dependencies = [
  "cow-utils",
  "criterion",
  "csv",
+ "flate2",
  "fst",
  "fxhash",
  "heed",

Cargo.toml

@@ -14,6 +14,7 @@ bstr = "0.2.13"
 byteorder = "1.3.4"
 cow-utils = "0.1.2"
 csv = "1.1.3"
+flate2 = "1.0.17"
 fst = "0.4.3"
 fxhash = "0.2.1"
 heed = { version = "0.8.1", default-features = false, features = ["lmdb"] }

src/bin/indexer.rs

@@ -1,5 +1,4 @@
-use std::convert::TryInto;
-use std::convert::TryFrom;
+use std::convert::{TryFrom, TryInto};
 use std::fs::{File, OpenOptions};
 use std::io::{self, Read, Write};
 use std::iter::FromIterator;
@@ -11,6 +10,7 @@ use anyhow::Context;
 use arc_cache::ArcCache;
 use bstr::ByteSlice as _;
 use cow_utils::CowUtils;
+use flate2::read::GzDecoder;
 use fst::IntoStreamer;
 use heed::EnvOpenOptions;
 use heed::types::*;
@@ -74,6 +74,9 @@ struct Opt {
 
     /// CSV file to index, if unspecified the CSV is read from standard input.
     ///
+    /// You can also provide a ".gz" or ".gzip" CSV file, the indexer will figure out
+    /// how to decode and read it.
+    ///
     /// Note that it is much faster to index from a file as when the indexer reads from stdin
     /// it will dedicate a thread for that and context switches could slow down the indexing jobs.
     csv_file: Option<PathBuf>,
@@ -501,7 +504,12 @@ fn main() -> anyhow::Result<()> {
             (0..num_threads)
                 .map(|_| {
                     let file = File::open(&file_path)?;
-                    let r = Box::new(file) as Box<dyn Read + Send>;
+                    // if the file extension is "gz" or "gzip" we can decode and read it.
+                    let r = if file_path.extension().map_or(false, |ext| ext == "gz" || ext == "gzip") {
+                        Box::new(GzDecoder::new(file)) as Box<dyn Read + Send>
+                    } else {
+                        Box::new(file) as Box<dyn Read + Send>
+                    };
                     Ok(csv::Reader::from_reader(r)) as io::Result<_>
                 })
                 .collect::<Result<Vec<_>, _>>()?