From 9ae42b606b41136292e2ba7c3f0b131a536a155f Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 14:48:47 -0800
Subject: [PATCH 01/11] Add repr(C) for ResourceKey

---
 provider/core/src/extract.rs  | 73 ++++++++++++++++++++++++++++++
 provider/core/src/lib.rs      |  2 +
 provider/core/src/resource.rs | 83 +++++++++++++++++++++++++++++------
 provider/core/tests/sizes.rs  |  6 ++-
 4 files changed, 148 insertions(+), 16 deletions(-)
 create mode 100644 provider/core/src/extract.rs

diff --git a/provider/core/src/extract.rs b/provider/core/src/extract.rs
new file mode 100644
index 00000000000..11c256e8d44
--- /dev/null
+++ b/provider/core/src/extract.rs
@@ -0,0 +1,73 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+//! Utilities for extracting `ResourceKey` objects from a byte stream. Requires the "std" feature.
+
+use crate::prelude::*;
+use std::io::BufRead;
+use std::io::BufReader;
+use std::io;
+
+pub fn extract_keys_from_byte_stream(stream: impl io::Read) -> io::Result<Vec<ResourceKey>> {
+    let mut reader = BufReader::with_capacity(1024, stream);
+    let mut working_buffer = [0u8; 1024 + 39];
+    let mut output = Vec::new();
+    loop {
+        let reader_buffer = reader.fill_buf()?;
+        if reader_buffer.len() == 0 {
+            break;
+        }
+        let len = reader_buffer.len();
+        // Save 39 bytes from iteration to iteration: one less than a 40-byte window
+        working_buffer[39..(39+len)].copy_from_slice(reader_buffer);
+        for window in working_buffer[..(39+len)].windows(40) {
+            if &window[0..8] == b"ICURES[[" && &window[36..40] == b"]]**" {
+                let mut bytes: [u8; 40] = [0; 40];
+                bytes.copy_from_slice(window);
+                let resc_key = match ResourceKey::from_repr_c(bytes) {
+                    Some(k) => k,
+                    None => continue
+                };
+                output.push(resc_key);
+            }
+        }
+        reader.consume(len);
+        working_buffer.copy_within(len.., 0);
+    }
+    output.sort();
+    output.dedup();
+    Ok(output)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::resource_key;
+
+    const GOLDEN_BYTES: &[u8] = b"\x00\x00ICURES[[\x02\x00\x00\x00\x00\x00\x00\x00skeletons\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00]]**ICURES[[\x02\x00\x00\x00\x00\x00\x00\x00symbols\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00]]**\x00\x00";
+
+    #[test]
+    fn test_extract_golden() {
+        let keys = extract_keys_from_byte_stream(&*GOLDEN_BYTES).unwrap();
+        assert_eq!(keys, vec![
+            resource_key!(DateTime, "skeletons", 1),
+            resource_key!(DateTime, "symbols", 1),
+        ]);
+    }
+
+    #[test]
+    fn test_extract_large() {
+        let keys: Vec<ResourceKey> = (0u8..=255u8).map(|i| resource_key!(Core, "demo", i)).collect();
+        let mut buffer: Vec<u8> = Vec::new();
+        for key in keys.iter() {
+            // Insert some garbage
+            buffer.extend(b"\x00ICURES[[\x00\x00]]**\x00\x00");
+            // This is safe because we are transmuting to a POD type
+            let key_bytes: [u8; 40] = unsafe { core::mem::transmute(*key) };
+            buffer.extend(&key_bytes);
+        }
+        let extracted_keys = extract_keys_from_byte_stream(&*buffer).unwrap();
+        assert_eq!(keys, extracted_keys);
+    }
+}
diff --git a/provider/core/src/lib.rs b/provider/core/src/lib.rs
index 703bddfd714..6ad62a2f27b 100644
--- a/provider/core/src/lib.rs
+++ b/provider/core/src/lib.rs
@@ -113,6 +113,8 @@ mod error;
 #[macro_use]
 pub mod erased;
 pub mod export;
+#[cfg(feature = "std")]
+pub mod extract;
 pub mod filter;
 pub mod hello_world;
 pub mod inv;
diff --git a/provider/core/src/resource.rs b/provider/core/src/resource.rs
index 94aa9696db0..2c624cddc2a 100644
--- a/provider/core/src/resource.rs
+++ b/provider/core/src/resource.rs
@@ -15,12 +15,13 @@ use core::default::Default;
 use core::fmt;
 use core::fmt::Write;
 use icu_locid::LanguageIdentifier;
-use tinystr::{TinyStr16, TinyStr4};
+use tinystr::{tinystr4, tinystr8, TinyStr16, TinyStr4, TinyStr8};
 use writeable::{LengthHint, Writeable};
 
 /// A top-level collection of related resource keys.
 #[non_exhaustive]
 #[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
+#[repr(C)]
 pub enum ResourceCategory {
     Core,
     Calendar,
@@ -79,10 +80,64 @@ impl writeable::Writeable for ResourceCategory {
 ///
 /// Use [`resource_key!`] as a shortcut to create resource keys in code.
 #[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone)]
+#[repr(C)]
 pub struct ResourceKey {
+    _tag0: TinyStr8,
     pub category: ResourceCategory,
     pub sub_category: TinyStr16,
-    pub version: u16,
+    pub version: u8,
+    _tag1: TinyStr4,
+}
+
+impl ResourceKey {
+    /// Creates a new [`ResourceKey`].
+    pub const fn new(
+        category: ResourceCategory,
+        sub_category: TinyStr16,
+        version: u8,
+    ) -> ResourceKey {
+        ResourceKey {
+            _tag0: tinystr8!("ICURES[["),
+            category,
+            sub_category,
+            version,
+            _tag1: tinystr4!("]]**"),
+        }
+    }
+
+    /// Recovers a [`ResourceKey`] from its `repr(C)` bytes.
+    /// 
+    /// Returns `None` if the bytes are not a valid [`ResourceKey`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use icu_provider::prelude::*;
+    ///
+    /// let demo_key = icu_provider::resource_key!(Core, "demo", 1);
+    /// // This is safe because we are transmuting to a POD type
+    /// let repr_c_bytes: [u8; 40] = unsafe {
+    ///     core::mem::transmute(demo_key)
+    /// };
+    /// let recovered_key = ResourceKey::from_repr_c(repr_c_bytes)
+    ///     .expect("The bytes are valid");
+    ///
+    /// assert_eq!(demo_key, recovered_key);
+    /// ```
+    pub fn from_repr_c(bytes: [u8; 40]) -> Option<ResourceKey> {
+        // Smoke check
+        if &bytes[0..8] != b"ICURES[[" || &bytes[36..40] != b"]]**" {
+            return None;
+        }
+
+        // TODO(#1457): Use a ULE-like code path here.
+        // TODO(#1457): This is not safe!
+        // - We can't currently verify the ResourceCategory!
+        // - TinyStr does not currently have a function that takes a byte *array* (with NULs).
+        unsafe {
+            Some(core::mem::transmute(bytes))
+        }
+    }
 }
 
 /// Shortcut to construct a const resource identifier.
@@ -119,11 +174,11 @@ macro_rules! resource_key {
         )
     };
     ($category:expr, $sub_category:literal, $version:tt) => {
-        $crate::ResourceKey {
-            category: $category,
-            sub_category: $crate::internal::tinystr16!($sub_category),
-            version: $version,
-        }
+        $crate::ResourceKey::new(
+            $category,
+            $crate::internal::tinystr16!($sub_category),
+            $version,
+        )
     };
 }
 
@@ -433,11 +488,11 @@ mod tests {
                 expected: "core/cardinal@1",
             },
             KeyTestCase {
-                resc_key: ResourceKey {
-                    category: ResourceCategory::PrivateUse(tinystr4!("priv")),
-                    sub_category: tinystr::tinystr16!("cardinal"),
-                    version: 1,
-                },
+                resc_key: ResourceKey::new(
+                    ResourceCategory::PrivateUse(tinystr4!("priv")),
+                    tinystr::tinystr16!("cardinal"),
+                    1,
+                ),
                 expected: "x-priv/cardinal@1",
             },
             KeyTestCase {
@@ -445,8 +500,8 @@ mod tests {
                 expected: "core/maxlengthsubcatg@1",
             },
             KeyTestCase {
-                resc_key: resource_key!(Core, "cardinal", 65535),
-                expected: "core/cardinal@65535",
+                resc_key: resource_key!(Core, "cardinal", 255),
+                expected: "core/cardinal@255",
             },
         ]
     }
diff --git a/provider/core/tests/sizes.rs b/provider/core/tests/sizes.rs
index f2377eea994..ea082694287 100644
--- a/provider/core/tests/sizes.rs
+++ b/provider/core/tests/sizes.rs
@@ -5,7 +5,9 @@
 use icu_provider::prelude::*;
 use static_assertions::const_assert_eq;
 
+const_assert_eq!(8, core::mem::size_of::<tinystr::TinyStr8>());
 const_assert_eq!(8, core::mem::size_of::<ResourceCategory>());
 const_assert_eq!(16, core::mem::size_of::<tinystr::TinyStr16>());
-const_assert_eq!(4, core::mem::size_of::<u32>());
-const_assert_eq!(32, core::mem::size_of::<ResourceKey>());
+const_assert_eq!(1, core::mem::size_of::<u8>());
+const_assert_eq!(4, core::mem::size_of::<tinystr::TinyStr4>());
+const_assert_eq!(40, core::mem::size_of::<ResourceKey>());

From b4c75aedab9f45cd8cabbd9c901d4b3209fbcbeb Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 15:25:29 -0800
Subject: [PATCH 02/11] Add icu4x-key-extract

---
 tools/datagen/Cargo.toml             |  5 ++
 tools/datagen/README.md              |  1 +
 tools/datagen/src/bin/key-extract.rs | 89 ++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 tools/datagen/src/bin/key-extract.rs

diff --git a/tools/datagen/Cargo.toml b/tools/datagen/Cargo.toml
index 3382f605568..e09d8a7c6b8 100644
--- a/tools/datagen/Cargo.toml
+++ b/tools/datagen/Cargo.toml
@@ -29,6 +29,7 @@ all-features = true
 [dependencies]
 eyre = "0.6"
 clap = "2.33"
+either = "1.6"
 futures = "0.3"
 icu_locid = { version = "0.4", path = "../../components/locid", features = ["std"]}
 icu_properties = { version = "0.4", path = "../../components/properties", features = ["std"]}
@@ -52,3 +53,7 @@ path = "src/bin/datagen.rs"
 [[bin]]
 name = "icu4x-testdata-download"
 path = "src/bin/testdata-download.rs"
+
+[[bin]]
+name = "icu4x-key-extract"
+path = "src/bin/key-extract.rs"
diff --git a/tools/datagen/README.md b/tools/datagen/README.md
index 5337abcc59d..9dad544448a 100644
--- a/tools/datagen/README.md
+++ b/tools/datagen/README.md
@@ -6,6 +6,7 @@ The tools include:
 
 1. `icu4x-datagen`: Read source data (CLDR JSON) and dump ICU4X-format data.
 2. `icu4x-testdata-download`: Download fresh CLDR JSON for testdata.
+3. `icu4x-key-extract`: Extract `ResourceKey` objects present in a compiled executable.
 
 More details on each tool can be found by running `--help`.
 
diff --git a/tools/datagen/src/bin/key-extract.rs b/tools/datagen/src/bin/key-extract.rs
new file mode 100644
index 00000000000..f51b10c0855
--- /dev/null
+++ b/tools/datagen/src/bin/key-extract.rs
@@ -0,0 +1,89 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use clap::{App, Arg};
+use either::Either;
+use eyre::WrapErr;
+use simple_logger::SimpleLogger;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() -> eyre::Result<()> {
+    let args = App::new("ICU4X Resource Key Extractor")
+        .version("0.0.1")
+        .author("The ICU4X Project Developers")
+        .about("Extract resource keys from a compiled binary")
+        .arg(
+            Arg::with_name("VERBOSE")
+                .short("v")
+                .long("verbose")
+                .multiple(true)
+                .help("Sets the level of verbosity (-v, -vv, or -vvv)"),
+        )
+        .arg(
+            Arg::with_name("INPUT")
+                .short("i")
+                .long("input")
+                .help(
+                    "Path to the file to scan. If omitted, reads from standard input."
+                )
+                .takes_value(true)
+        )
+        .arg(
+            Arg::with_name("OUTPUT")
+                .short("o")
+                .long("out")
+                .help(
+                    "Path to a file to print the detected resource keys. If omitted, writes to standard output.",
+                )
+                .takes_value(true)
+        )
+        .get_matches();
+
+    match args.occurrences_of("VERBOSE") {
+        0 => SimpleLogger::new()
+            .env()
+            .with_level(log::LevelFilter::Info)
+            .init()
+            .unwrap(),
+        1 => SimpleLogger::new()
+            .with_level(log::LevelFilter::Debug)
+            .init()
+            .unwrap(),
+        2 => SimpleLogger::new()
+            .with_level(log::LevelFilter::Trace)
+            .init()
+            .unwrap(),
+        _ => eyre::bail!("Only -v and -vv are supported"),
+    }
+
+    let read_stream: Either<_, _> = match args.value_of("INPUT") {
+        Some(path_str) => {
+            let path_buf = PathBuf::from(path_str);
+            Either::Left(
+                File::open(&path_buf).with_context(|| path_buf.to_string_lossy().into_owned())?,
+            )
+        }
+        None => Either::Right(std::io::stdin()),
+    };
+
+    let mut write_stream: Either<_, _> = match args.value_of("OUTPUT") {
+        Some(path_str) => {
+            let path_buf = PathBuf::from(path_str);
+            Either::Left(
+                File::create(&path_buf).with_context(|| path_buf.to_string_lossy().into_owned())?,
+            )
+        }
+        None => Either::Right(std::io::stdout()),
+    };
+
+    let keys = icu_provider::extract::extract_keys_from_byte_stream(read_stream)?;
+
+    for key in keys {
+        writeln!(write_stream, "{}", key)?;
+    }
+
+    Ok(())
+}

From c511e8d9b6b72a0841a04ea4af4b969871ba2ad2 Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 17:06:39 -0800
Subject: [PATCH 03/11] Add icu4x-key-extract test to CI

---
 .github/workflows/build-test.yml              | 15 +++--
 Makefile.toml                                 |  2 +
 provider/core/src/extract.rs                  |  2 +-
 provider/core/src/resource.rs                 |  4 +-
 .../datagen/tests/testdata/work_log+keys.txt  |  4 ++
 tools/scripts/data.toml                       | 28 ++++++++++
 tools/scripts/wasm.toml                       | 56 +++++++++++++++++++
 7 files changed, 103 insertions(+), 8 deletions(-)
 create mode 100644 tools/datagen/tests/testdata/work_log+keys.txt

diff --git a/.github/workflows/build-test.yml b/.github/workflows/build-test.yml
index 0a3a395f14c..dfbf13e8052 100644
--- a/.github/workflows/build-test.yml
+++ b/.github/workflows/build-test.yml
@@ -231,6 +231,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+      - name: Install Node.js v14.17.0
+        uses: actions/setup-node@v1
+        with:
+          node-version: 14.17.0
       - name: Load nightly Rust toolchain for WASM.
         run: |
           rustup install nightly-2021-12-22
@@ -320,15 +324,16 @@ jobs:
         with:
           command: make
           args: wasm-release
-      - name: Install Node.js v14.17.0
-        uses: actions/setup-node@v1
-        with:
-          node-version: 14.17.0
-      - name: Build
+      - name: Test
         uses: actions-rs/cargo@v1.0.1
         with:
           command: make
           args: wasm-test-release
+      - name: Build Examples and test icu4x-key-extract
+        uses: actions-rs/cargo@v1.0.1
+        with:
+          command: make
+          args: wasm-compare-worklog-keys
       # This has to be a separate test since the emscripten sdk
       # will otherwise interfere with other node-using tests
       - name: Run emscripten test
diff --git a/Makefile.toml b/Makefile.toml
index 2f66eb57583..6f4d74d5fde 100644
--- a/Makefile.toml
+++ b/Makefile.toml
@@ -91,6 +91,8 @@ dependencies = [
     # we have to set up the environment for the emscripten job separately
     # Instead, each of these is called individually.
     "wasm-release",
+    "wasm-test-release",
+    "wasm-compare-worklog-keys",
     "wasm-cpp-emscripten",
 ]
 
diff --git a/provider/core/src/extract.rs b/provider/core/src/extract.rs
index 11c256e8d44..4c493ab5dd4 100644
--- a/provider/core/src/extract.rs
+++ b/provider/core/src/extract.rs
@@ -25,7 +25,7 @@ pub fn extract_keys_from_byte_stream(stream: impl io::Read) -> io::Result<Vec<Re
             if &window[0..8] == b"ICURES[[" && &window[36..40] == b"]]**" {
                 let mut bytes: [u8; 40] = [0; 40];
                 bytes.copy_from_slice(window);
-                let resc_key = match ResourceKey::from_repr_c(bytes) {
+                let resc_key = match ResourceKey::from_repr_c(&bytes) {
                     Some(k) => k,
                     None => continue
                 };
diff --git a/provider/core/src/resource.rs b/provider/core/src/resource.rs
index 2c624cddc2a..79e9ce3c15a 100644
--- a/provider/core/src/resource.rs
+++ b/provider/core/src/resource.rs
@@ -124,7 +124,7 @@ impl ResourceKey {
     ///
     /// assert_eq!(demo_key, recovered_key);
     /// ```
-    pub fn from_repr_c(bytes: [u8; 40]) -> Option<ResourceKey> {
+    pub fn from_repr_c(bytes: &[u8; 40]) -> Option<ResourceKey> {
         // Smoke check
         if &bytes[0..8] != b"ICURES[[" || &bytes[36..40] != b"]]**" {
             return None;
@@ -135,7 +135,7 @@ impl ResourceKey {
         // - We can't currently verify the ResourceCategory!
         // - TinyStr does not currently have a function that takes a byte *array* (with NULs).
         unsafe {
-            Some(core::mem::transmute(bytes))
+            Some(core::mem::transmute(*bytes))
         }
     }
 }
diff --git a/tools/datagen/tests/testdata/work_log+keys.txt b/tools/datagen/tests/testdata/work_log+keys.txt
new file mode 100644
index 00000000000..9f03fd10b11
--- /dev/null
+++ b/tools/datagen/tests/testdata/work_log+keys.txt
@@ -0,0 +1,4 @@
+datetime/lengths@1
+datetime/skeletons@1
+datetime/symbols@1
+plurals/ordinal@1
diff --git a/tools/scripts/data.toml b/tools/scripts/data.toml
index f7668eae749..5fccdd58444 100644
--- a/tools/scripts/data.toml
+++ b/tools/scripts/data.toml
@@ -15,6 +15,17 @@ args = [
     "-v",
 ]
 
+[tasks.icu4x-key-extract]
+description = "Build and smoke-test the icu4x-key-extract tool"
+category = "ICU4X Data"
+command = "cargo"
+args = [
+    "run",
+    "--bin=icu4x-key-extract",
+    "--",
+    "--help",
+]
+
 [tasks.testdata-build-json]
 description = "Build ICU4X JSON from the downloaded CLDR JSON, overwriting the existing ICU4X JSON."
 category = "ICU4X Data"
@@ -65,6 +76,22 @@ args = [
     "--overwrite",
 ]
 
+[tasks.testdata-build-worklog-json]
+description = "Build JSON files for the work_log example"
+category = "ICU4X Data"
+command = "cargo"
+args = [
+    "run",
+    "--bin=icu4x-datagen",
+    "--",
+    "--input-from-testdata",
+    "--out=tools/datagen/tests/testdata/work_log_json",
+    "--key-file=tools/datagen/tests/testdata/work_log+keys.txt",
+    "--locales=de",
+    "--locales=es",
+    "--overwrite",
+]
+
 [tasks.testdata]
 description = "Rebuild all ICU4X testdata from source data checked into the repository"
 category = "ICU4X Data"
@@ -72,6 +99,7 @@ dependencies = [
     "testdata-build-json",
     "testdata-build-blob",
     "testdata-build-blob-smaller",
+    "testdata-build-worklog-json",
 ]
 
 [tasks.testdata-check]
diff --git a/tools/scripts/wasm.toml b/tools/scripts/wasm.toml
index f1717a37bef..5c84478bb5f 100644
--- a/tools/scripts/wasm.toml
+++ b/tools/scripts/wasm.toml
@@ -334,6 +334,62 @@ end
 '''
 dependencies = ["wasm-wasm-examples"]
 
+[tasks.wasm-key-extract-examples]
+description = "Run icu4x-key-extract on WASM files"
+category = "ICU4X WASM"
+script_runner = "@duckscript"
+script = '''
+exit_on_error true
+
+mkdir wasmpkg/keys
+
+handle = glob_array wasmpkg/*.wasm
+for src_path in ${handle}
+    path_no_extension = substring ${src_path} -5
+    basename = substring ${path_no_extension} 8
+    out_path = concat wasmpkg/keys/ ${basename} "+keys.txt"
+
+    out_exists = is_path_exists ${out_path}
+    up_to_date = set false
+    if ${out_exists}
+        src_time = get_last_modified_time ${src_path}
+        out_time = get_last_modified_time ${out_path}
+        up_to_date = less_than ${src_time} ${out_time}
+    end
+
+    if not ${up_to_date}
+        echo Writing ${out_path}
+        exec --fail-on-error cargo run --bin icu4x-key-extract -- -i ${src_path} -o ${out_path}
+    end
+end
+'''
+dependencies = ["wasm-wasm-examples", "icu4x-key-extract"]
+
+[tasks.wasm-compare-worklog-keys]
+description = "Compare the generated worklog key file with the golden version"
+category = "ICU4X WASM"
+script_runner = "@duckscript"
+script = '''
+exit_on_error true
+
+expected = readfile tools/datagen/tests/testdata/work_log+keys.txt
+actual = readfile wasmpkg/keys/work_log+keys.txt
+are_equal = eq ${expected} ${actual}
+
+if ${are_equal}
+    exit 0
+else
+    echo "*****"
+    echo "work_log+keys.txt do not match! Actual generated output:"
+    echo ""
+    echo ${actual}
+    echo "If this is expected, copy the above output into tools/datagen/tests/testdata/work_log+keys.txt"
+    echo "*****"
+    exit 1
+end
+'''
+dependencies = ["wasm-key-extract-examples"]
+
 [tasks.wasm-dev]
 description = "All-in-one command to build dev-mode WASM FFI to wasmpkg"
 category = "ICU4X WASM"

From 84660258091d8e8e77707136107c0e216a05caf2 Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 17:51:57 -0800
Subject: [PATCH 04/11] Add support for and test --key-file in icu4x-datagen

---
 .gitignore                       |  1 +
 Cargo.lock                       |  1 +
 tools/datagen/src/bin/datagen.rs | 37 ++++++++++++++++++++++----------
 tools/scripts/data.toml          | 33 ++++++++++++++--------------
 4 files changed, 45 insertions(+), 27 deletions(-)

diff --git a/.gitignore b/.gitignore
index 799786906a2..3c63338f000 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,6 +23,7 @@ dhat-heap.json
 
 # Do not check-in bincode test data
 provider/testdata/data/bincode
+tools/datagen/tests/testdata/work_log_bincode
 
 # Ignore irrelevant files that get generated on macOS
 **/.DS_Store
diff --git a/Cargo.lock b/Cargo.lock
index c7b5d59c6c6..3234fde405d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1096,6 +1096,7 @@ name = "icu_datagen"
 version = "0.4.0"
 dependencies = [
  "clap",
+ "either",
  "eyre",
  "futures",
  "icu_locid",
diff --git a/tools/datagen/src/bin/datagen.rs b/tools/datagen/src/bin/datagen.rs
index 5bb35054e3b..e1762174ab0 100644
--- a/tools/datagen/src/bin/datagen.rs
+++ b/tools/datagen/src/bin/datagen.rs
@@ -27,6 +27,10 @@ use simple_logger::SimpleLogger;
 use std::collections::HashSet;
 use std::path::PathBuf;
 use std::str::FromStr;
+use std::io;
+use std::io::BufRead;
+use std::fs::File;
+use std::borrow::Cow;
 use writeable::Writeable;
 
 fn main() -> eyre::Result<()> {
@@ -240,10 +244,6 @@ fn main() -> eyre::Result<()> {
             .unwrap()
     }
 
-    if matches.is_present("KEY_FILE") {
-        eyre::bail!("Key file is not yet supported (see #192)",);
-    }
-
     if matches.is_present("DRY_RUN") {
         eyre::bail!("Dry-run is not yet supported");
     }
@@ -280,14 +280,29 @@ fn main() -> eyre::Result<()> {
         _ => unreachable!(),
     };
 
+    let mut allowed_keys: Option<HashSet<Cow<str>>> = None;
+    if let Some(keys) = matches.values_of("KEYS") {
+        let allowed_keys = allowed_keys.get_or_insert_with(Default::default);
+        allowed_keys.extend(keys.map(|s| Cow::Borrowed(s)));
+    }
+    if let Some(key_file_path) = matches.value_of_os("KEY_FILE") {
+        // eyre::bail!("Key file is not yet supported (see #192)",);
+        let allowed_keys = allowed_keys.get_or_insert_with(Default::default);
+        let file = File::open(key_file_path).with_context(|| key_file_path.to_string_lossy().into_owned())?;
+        for line in io::BufReader::new(file).lines() {
+            let line_string = line.with_context(|| key_file_path.to_string_lossy().into_owned())?;
+            allowed_keys.insert(Cow::Owned(line_string));
+        }
+    }
+
     if matches.is_present("ALL_KEYS")
         || matches.is_present("KEYS")
+        || matches.is_present("KEY_FILE")
         || matches.is_present("TEST_KEYS")
     {
-        let keys = matches.values_of("KEYS").map(|values| values.collect());
-        export_cldr(&matches, exporter, locales_vec.as_deref(), keys.as_ref())?;
-        export_set_props(&matches, exporter, keys.as_ref())?;
-        export_map_props(&matches, exporter, keys.as_ref())?;
+        export_cldr(&matches, exporter, locales_vec.as_deref(), allowed_keys.as_ref())?;
+        export_set_props(&matches, exporter, allowed_keys.as_ref())?;
+        export_map_props(&matches, exporter, allowed_keys.as_ref())?;
     }
 
     if matches.is_present("HELLO_WORLD") {
@@ -379,7 +394,7 @@ fn export_cldr(
     matches: &ArgMatches,
     exporter: &mut (impl DataExporter<SerializeMarker> + ?Sized),
     allowed_locales: Option<&[LanguageIdentifier]>,
-    allowed_keys: Option<&HashSet<&str>>,
+    allowed_keys: Option<&HashSet<Cow<str>>>,
 ) -> eyre::Result<()> {
     let locale_subset = matches.value_of("CLDR_LOCALE_SUBSET").unwrap_or("full");
     let cldr_paths: Box<dyn CldrPaths> = if let Some(tag) = matches.value_of("CLDR_TAG") {
@@ -437,7 +452,7 @@ fn export_cldr(
 fn export_set_props(
     matches: &ArgMatches,
     exporter: &mut (impl DataExporter<SerializeMarker> + ?Sized),
-    allowed_keys: Option<&HashSet<&str>>,
+    allowed_keys: Option<&HashSet<Cow<str>>>,
 ) -> eyre::Result<()> {
     log::trace!("Loading data for binary properties...");
 
@@ -485,7 +500,7 @@ fn export_set_props(
 fn export_map_props(
     matches: &ArgMatches,
     exporter: &mut (impl DataExporter<SerializeMarker> + ?Sized),
-    allowed_keys: Option<&HashSet<&str>>,
+    allowed_keys: Option<&HashSet<Cow<str>>>,
 ) -> eyre::Result<()> {
     log::trace!("Loading data for enumerated properties...");
 
diff --git a/tools/scripts/data.toml b/tools/scripts/data.toml
index 5fccdd58444..9aaaaaa0d87 100644
--- a/tools/scripts/data.toml
+++ b/tools/scripts/data.toml
@@ -76,22 +76,6 @@ args = [
     "--overwrite",
 ]
 
-[tasks.testdata-build-worklog-json]
-description = "Build JSON files for the work_log example"
-category = "ICU4X Data"
-command = "cargo"
-args = [
-    "run",
-    "--bin=icu4x-datagen",
-    "--",
-    "--input-from-testdata",
-    "--out=tools/datagen/tests/testdata/work_log_json",
-    "--key-file=tools/datagen/tests/testdata/work_log+keys.txt",
-    "--locales=de",
-    "--locales=es",
-    "--overwrite",
-]
-
 [tasks.testdata]
 description = "Rebuild all ICU4X testdata from source data checked into the repository"
 category = "ICU4X Data"
@@ -155,3 +139,20 @@ args = [
     "--syntax=bincode",
     "--overwrite",
 ]
+
+[tasks.testdata-build-worklog-bincode]
+description = "Build Bincode files for the work_log example"
+category = "ICU4X Data"
+command = "cargo"
+args = [
+    "run",
+    "--bin=icu4x-datagen",
+    "--",
+    "--input-from-testdata",
+    "--out=tools/datagen/tests/testdata/work_log_bincode",
+    "--key-file=tools/datagen/tests/testdata/work_log+keys.txt",
+    "--locales=de",
+    "--locales=es",
+    "--syntax=bincode",
+    "--overwrite",
+]

From 22cabee43dfc5a99f4dcac0afcca92be601d5b9d Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 18:00:47 -0800
Subject: [PATCH 05/11] Update docs for new icu4x-key-extract tool

---
 tools/datagen/README.md   | 35 ++++++++++----------
 tools/datagen/src/main.rs | 68 +++++++++++++++++++--------------------
 2 files changed, 51 insertions(+), 52 deletions(-)

diff --git a/tools/datagen/README.md b/tools/datagen/README.md
index 9dad544448a..be4eb5b2894 100644
--- a/tools/datagen/README.md
+++ b/tools/datagen/README.md
@@ -12,39 +12,38 @@ More details on each tool can be found by running `--help`.
 
 ## Examples
 
-Generate ICU4X JSON file tree:
+Generate ICU4X Postcard blob (single file) for all keys and all locales:
 
 ```bash
 # Run from the icu4x project folder
 $ cargo run --bin icu4x-datagen -- \
-   --cldr-tag 39.0.0 \
-   --all-keys \
-   --all-locales \
-   --out /tmp/icu4x_data/json
+    --cldr-tag 39.0.0 \
+    --all-keys \
+    --all-locales \
+    --format blob \
+    --out /tmp/icu4x_data/icu4x_data.postcard
 ```
 
-Generate ICU4X Postcard blob (single file):
+Extract the keys from an executable into a key file:
 
 ```bash
 # Run from the icu4x project folder
-$ cargo run --bin icu4x-datagen -- \
-   --cldr-tag 39.0.0 \
-   --all-keys \
-   --all-locales \
-   --format blob \
-   --out /tmp/icu4x_data/icu4x_data.postcard
+$ cargo build --example work_log
+$ cargo run --bin icu4x-key-extract -- \
+    -i target/debug/examples/work_log
+    -o /tmp/icu4x_data/work_log+keys.txt
 ```
 
-Generate ICU4X Bincode file tree:
+Generate ICU4X JSON file tree from the key file for Spanish and German:
 
 ```bash
 # Run from the icu4x project folder
 $ cargo run --bin icu4x-datagen -- \
-   --cldr-tag 39.0.0 \
-   --all-keys \
-   --all-locales \
-   --syntax bincode \
-   --out /tmp/icu4x_data/bincode
+    --cldr-tag 39.0.0 \
+    --key-file /tmp/icu4x_data/work_log+keys.txt \
+    --locales es \
+    --locales de \
+    --out /tmp/icu4x_data/work_log_json
 ```
 
 ## More Information
diff --git a/tools/datagen/src/main.rs b/tools/datagen/src/main.rs
index 0b70db1c863..e38627bcd3c 100644
--- a/tools/datagen/src/main.rs
+++ b/tools/datagen/src/main.rs
@@ -8,45 +8,45 @@
 //!
 //! 1. `icu4x-datagen`: Read source data (CLDR JSON) and dump ICU4X-format data.
 //! 2. `icu4x-testdata-download`: Download fresh CLDR JSON for testdata.
+//! 3. `icu4x-key-extract`: Extract `ResourceKey` objects present in a compiled executable.
 //!
 //! More details on each tool can be found by running `--help`.
 //!
 //! # Examples
 //!
-//! Generate ICU4X JSON file tree:
-//!
-//!```bash
-//!# Run from the icu4x project folder
-//!$ cargo run --bin icu4x-datagen -- \
-//!    --cldr-tag 39.0.0 \
-//!    --all-keys \
-//!    --all-locales \
-//!    --out /tmp/icu4x_data/json
-//!```
-//!
-//! Generate ICU4X Postcard blob (single file):
-//!
-//!```bash
-//!# Run from the icu4x project folder
-//!$ cargo run --bin icu4x-datagen -- \
-//!    --cldr-tag 39.0.0 \
-//!    --all-keys \
-//!    --all-locales \
-//!    --format blob \
-//!    --out /tmp/icu4x_data/icu4x_data.postcard
-//!```
-//!
-//! Generate ICU4X Bincode file tree:
-//!
-//!```bash
-//!# Run from the icu4x project folder
-//!$ cargo run --bin icu4x-datagen -- \
-//!    --cldr-tag 39.0.0 \
-//!    --all-keys \
-//!    --all-locales \
-//!    --syntax bincode \
-//!    --out /tmp/icu4x_data/bincode
-//!```
+//! Generate ICU4X Postcard blob (single file) for all keys and all locales:
+//!
+//! ```bash
+//! # Run from the icu4x project folder
+//! $ cargo run --bin icu4x-datagen -- \
+//!     --cldr-tag 39.0.0 \
+//!     --all-keys \
+//!     --all-locales \
+//!     --format blob \
+//!     --out /tmp/icu4x_data/icu4x_data.postcard
+//! ```
+//! 
+//! Extract the keys from an executable into a key file:
+//! 
+//! ```bash
+//! # Run from the icu4x project folder
+//! $ cargo build --example work_log
+//! $ cargo run --bin icu4x-key-extract -- \
+//!     -i target/debug/examples/work_log
+//!     -o /tmp/icu4x_data/work_log+keys.txt
+//! ```
+//!
+//! Generate ICU4X JSON file tree from the key file for Spanish and German:
+//!
+//! ```bash
+//! # Run from the icu4x project folder
+//! $ cargo run --bin icu4x-datagen -- \
+//!     --cldr-tag 39.0.0 \
+//!     --key-file /tmp/icu4x_data/work_log+keys.txt \
+//!     --locales es \
+//!     --locales de \
+//!     --out /tmp/icu4x_data/work_log_json
+//! ```
 
 fn main() {
     panic!("Please run a more specific binary")

From 596e252a159e4249504a347af854a42f0f687a19 Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 18:11:07 -0800
Subject: [PATCH 06/11] Update readmes again

---
 tools/datagen/README.md   | 5 +++--
 tools/datagen/src/main.rs | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/datagen/README.md b/tools/datagen/README.md
index be4eb5b2894..84116467c8c 100644
--- a/tools/datagen/README.md
+++ b/tools/datagen/README.md
@@ -28,10 +28,11 @@ Extract the keys from an executable into a key file:
 
 ```bash
 # Run from the icu4x project folder
-$ cargo build --example work_log
+$ cargo build --example work_log --release
 $ cargo run --bin icu4x-key-extract -- \
-    -i target/debug/examples/work_log
+    -i target/release/examples/work_log \
     -o /tmp/icu4x_data/work_log+keys.txt
+$ cat /tmp/icu4x_data/work_log+keys.txt
 ```
 
 Generate ICU4X JSON file tree from the key file for Spanish and German:
diff --git a/tools/datagen/src/main.rs b/tools/datagen/src/main.rs
index e38627bcd3c..466332214e2 100644
--- a/tools/datagen/src/main.rs
+++ b/tools/datagen/src/main.rs
@@ -30,10 +30,11 @@
 //! 
 //! ```bash
 //! # Run from the icu4x project folder
-//! $ cargo build --example work_log
+//! $ cargo build --example work_log --release
 //! $ cargo run --bin icu4x-key-extract -- \
-//!     -i target/debug/examples/work_log
+//!     -i target/release/examples/work_log \
 //!     -o /tmp/icu4x_data/work_log+keys.txt
+//! $ cat /tmp/icu4x_data/work_log+keys.txt
 //! ```
 //!
 //! Generate ICU4X JSON file tree from the key file for Spanish and German:

From 87c93d11b546042e564af4a433ac01dce468d810 Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 18:16:01 -0800
Subject: [PATCH 07/11] fmt

---
 provider/core/src/extract.rs     | 23 ++++++++++++++---------
 provider/core/src/resource.rs    |  6 ++----
 tools/datagen/src/bin/datagen.rs | 18 ++++++++++++------
 tools/datagen/src/main.rs        |  4 ++--
 4 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/provider/core/src/extract.rs b/provider/core/src/extract.rs
index 4c493ab5dd4..5cdd4445d59 100644
--- a/provider/core/src/extract.rs
+++ b/provider/core/src/extract.rs
@@ -5,9 +5,9 @@
 //! Utilities for extracting `ResourceKey` objects from a byte stream. Requires the "std" feature.
 
 use crate::prelude::*;
+use std::io;
 use std::io::BufRead;
 use std::io::BufReader;
-use std::io;
 
 pub fn extract_keys_from_byte_stream(stream: impl io::Read) -> io::Result<Vec<ResourceKey>> {
     let mut reader = BufReader::with_capacity(1024, stream);
@@ -20,14 +20,14 @@ pub fn extract_keys_from_byte_stream(stream: impl io::Read) -> io::Result<Vec<Re
         }
         let len = reader_buffer.len();
         // Save 39 bytes from iteration to iteration: one less than a 40-byte window
-        working_buffer[39..(39+len)].copy_from_slice(reader_buffer);
-        for window in working_buffer[..(39+len)].windows(40) {
+        working_buffer[39..(39 + len)].copy_from_slice(reader_buffer);
+        for window in working_buffer[..(39 + len)].windows(40) {
             if &window[0..8] == b"ICURES[[" && &window[36..40] == b"]]**" {
                 let mut bytes: [u8; 40] = [0; 40];
                 bytes.copy_from_slice(window);
                 let resc_key = match ResourceKey::from_repr_c(&bytes) {
                     Some(k) => k,
-                    None => continue
+                    None => continue,
                 };
                 output.push(resc_key);
             }
@@ -50,15 +50,20 @@ mod test {
     #[test]
     fn test_extract_golden() {
         let keys = extract_keys_from_byte_stream(&*GOLDEN_BYTES).unwrap();
-        assert_eq!(keys, vec![
-            resource_key!(DateTime, "skeletons", 1),
-            resource_key!(DateTime, "symbols", 1),
-        ]);
+        assert_eq!(
+            keys,
+            vec![
+                resource_key!(DateTime, "skeletons", 1),
+                resource_key!(DateTime, "symbols", 1),
+            ]
+        );
     }
 
     #[test]
     fn test_extract_large() {
-        let keys: Vec<ResourceKey> = (0u8..=255u8).map(|i| resource_key!(Core, "demo", i)).collect();
+        let keys: Vec<ResourceKey> = (0u8..=255u8)
+            .map(|i| resource_key!(Core, "demo", i))
+            .collect();
         let mut buffer: Vec<u8> = Vec::new();
         for key in keys.iter() {
             // Insert some garbage
diff --git a/provider/core/src/resource.rs b/provider/core/src/resource.rs
index 79e9ce3c15a..49adb8c21a0 100644
--- a/provider/core/src/resource.rs
+++ b/provider/core/src/resource.rs
@@ -106,7 +106,7 @@ impl ResourceKey {
     }
 
     /// Recovers a [`ResourceKey`] from its `repr(C)` bytes.
-    /// 
+    ///
     /// Returns `None` if the bytes are not a valid [`ResourceKey`].
     ///
     /// # Examples
@@ -134,9 +134,7 @@ impl ResourceKey {
         // TODO(#1457): This is not safe!
         // - We can't currently verify the ResourceCategory!
         // - TinyStr does not currently have a function that takes a byte *array* (with NULs).
-        unsafe {
-            Some(core::mem::transmute(*bytes))
-        }
+        unsafe { Some(core::mem::transmute(*bytes)) }
     }
 }
 
diff --git a/tools/datagen/src/bin/datagen.rs b/tools/datagen/src/bin/datagen.rs
index e1762174ab0..d1715fe944f 100644
--- a/tools/datagen/src/bin/datagen.rs
+++ b/tools/datagen/src/bin/datagen.rs
@@ -24,13 +24,13 @@ use icu_provider_fs::export::FilesystemExporter;
 use icu_provider_fs::manifest;
 use icu_provider_uprops::{EnumeratedPropertyCodePointTrieProvider, PropertiesDataProvider};
 use simple_logger::SimpleLogger;
+use std::borrow::Cow;
 use std::collections::HashSet;
-use std::path::PathBuf;
-use std::str::FromStr;
+use std::fs::File;
 use std::io;
 use std::io::BufRead;
-use std::fs::File;
-use std::borrow::Cow;
+use std::path::PathBuf;
+use std::str::FromStr;
 use writeable::Writeable;
 
 fn main() -> eyre::Result<()> {
@@ -288,7 +288,8 @@ fn main() -> eyre::Result<()> {
     if let Some(key_file_path) = matches.value_of_os("KEY_FILE") {
         // eyre::bail!("Key file is not yet supported (see #192)",);
         let allowed_keys = allowed_keys.get_or_insert_with(Default::default);
-        let file = File::open(key_file_path).with_context(|| key_file_path.to_string_lossy().into_owned())?;
+        let file = File::open(key_file_path)
+            .with_context(|| key_file_path.to_string_lossy().into_owned())?;
         for line in io::BufReader::new(file).lines() {
             let line_string = line.with_context(|| key_file_path.to_string_lossy().into_owned())?;
             allowed_keys.insert(Cow::Owned(line_string));
@@ -300,7 +301,12 @@ fn main() -> eyre::Result<()> {
         || matches.is_present("KEY_FILE")
         || matches.is_present("TEST_KEYS")
     {
-        export_cldr(&matches, exporter, locales_vec.as_deref(), allowed_keys.as_ref())?;
+        export_cldr(
+            &matches,
+            exporter,
+            locales_vec.as_deref(),
+            allowed_keys.as_ref(),
+        )?;
         export_set_props(&matches, exporter, allowed_keys.as_ref())?;
         export_map_props(&matches, exporter, allowed_keys.as_ref())?;
     }
diff --git a/tools/datagen/src/main.rs b/tools/datagen/src/main.rs
index 466332214e2..07c5cf2cddb 100644
--- a/tools/datagen/src/main.rs
+++ b/tools/datagen/src/main.rs
@@ -25,9 +25,9 @@
 //!     --format blob \
 //!     --out /tmp/icu4x_data/icu4x_data.postcard
 //! ```
-//! 
+//!
 //! Extract the keys from an executable into a key file:
-//! 
+//!
 //! ```bash
 //! # Run from the icu4x project folder
 //! $ cargo build --example work_log --release

From 6e8b75de8e62b5e91bbd8caab35df3845dd7941b Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 18:22:23 -0800
Subject: [PATCH 08/11] Add missing docs

---
 provider/core/src/extract.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/provider/core/src/extract.rs b/provider/core/src/extract.rs
index 5cdd4445d59..b62380ce1c3 100644
--- a/provider/core/src/extract.rs
+++ b/provider/core/src/extract.rs
@@ -9,13 +9,21 @@ use std::io;
 use std::io::BufRead;
 use std::io::BufReader;
 
+/// Extracts [`ResourceKey`] objects from a byte stream.
+///
+/// This function looks for all occurrences of the `repr(C)` of `ResourceKey` in the byte stream,
+/// and reads them back as Rust objects.
+///
+/// The byte stream is often the output of a compiler, like a WASM file or an x86 executable.
+///
+/// To run this function as a command-line tool, use `icu4x-key-extract`.
 pub fn extract_keys_from_byte_stream(stream: impl io::Read) -> io::Result<Vec<ResourceKey>> {
     let mut reader = BufReader::with_capacity(1024, stream);
     let mut working_buffer = [0u8; 1024 + 39];
     let mut output = Vec::new();
     loop {
         let reader_buffer = reader.fill_buf()?;
-        if reader_buffer.len() == 0 {
+        if reader_buffer.is_empty() {
             break;
         }
         let len = reader_buffer.len();

From 2f7e1c231a6edb7e7cf325c6bee322c0333cc889 Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 20:55:47 -0800
Subject: [PATCH 09/11] Fix up bincode jobs

---
 Makefile.toml           | 2 +-
 tools/scripts/data.toml | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/Makefile.toml b/Makefile.toml
index 6f4d74d5fde..b643b027119 100644
--- a/Makefile.toml
+++ b/Makefile.toml
@@ -48,7 +48,7 @@ dependencies = [
     "test-all-features",
     "test-docs-default",
     "test-docs",
-    "testdata-build-bincode-all",
+    "testdata-build-worklog-bincode",
     "testdata-check",
 ]
 
diff --git a/tools/scripts/data.toml b/tools/scripts/data.toml
index 9aaaaaa0d87..5b3121372a7 100644
--- a/tools/scripts/data.toml
+++ b/tools/scripts/data.toml
@@ -83,7 +83,6 @@ dependencies = [
     "testdata-build-json",
     "testdata-build-blob",
     "testdata-build-blob-smaller",
-    "testdata-build-worklog-json",
 ]
 
 [tasks.testdata-check]

From 63b08a54b48f7d730f34274f4b7fc18268d2afdd Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Thu, 30 Dec 2021 23:37:39 -0800
Subject: [PATCH 10/11] Fix docs test

---
 provider/core/src/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/provider/core/src/resource.rs b/provider/core/src/resource.rs
index 49adb8c21a0..1df56960ea5 100644
--- a/provider/core/src/resource.rs
+++ b/provider/core/src/resource.rs
@@ -119,7 +119,7 @@ impl ResourceKey {
     /// let repr_c_bytes: [u8; 40] = unsafe {
     ///     core::mem::transmute(demo_key)
     /// };
-    /// let recovered_key = ResourceKey::from_repr_c(repr_c_bytes)
+    /// let recovered_key = ResourceKey::from_repr_c(&repr_c_bytes)
     ///     .expect("The bytes are valid");
     ///
     /// assert_eq!(demo_key, recovered_key);

From b665dbb1c51a882214d781681eabfe84fc20feb1 Mon Sep 17 00:00:00 2001
From: "Shane F. Carr" <shane@unicode.org>
Date: Fri, 31 Dec 2021 11:16:59 -0800
Subject: [PATCH 11/11] Remove obsolete comment

---
 tools/datagen/src/bin/datagen.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tools/datagen/src/bin/datagen.rs b/tools/datagen/src/bin/datagen.rs
index d1715fe944f..13a4308cdb1 100644
--- a/tools/datagen/src/bin/datagen.rs
+++ b/tools/datagen/src/bin/datagen.rs
@@ -286,7 +286,6 @@ fn main() -> eyre::Result<()> {
         allowed_keys.extend(keys.map(|s| Cow::Borrowed(s)));
     }
     if let Some(key_file_path) = matches.value_of_os("KEY_FILE") {
-        // eyre::bail!("Key file is not yet supported (see #192)",);
         let allowed_keys = allowed_keys.get_or_insert_with(Default::default);
         let file = File::open(key_file_path)
             .with_context(|| key_file_path.to_string_lossy().into_owned())?;