3 files changed, 78 insertions, 16 deletions
diff --git a/build_extra/rust/get_version_hash.py b/build_extra/rust/get_version_hash.py
deleted file mode 100644
index 7d37cbf9b..000000000
--- a/build_extra/rust/get_version_hash.py
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright 2018 the Deno authors. All rights reserved. MIT license.
-
-# This script computes the sha256sum of the first command line argument, and
-# writes a few hex digits of it to stdout. It is used by rust.gni to derive a
-# unique string (without dots/special characters) from a crate version number.
-
-from hashlib import sha256
-import sys
-
-if len(sys.argv) != 2:
-    raise Exception('Expected exactly one argument.')
-
-hash = sha256(sys.argv[1]).hexdigest()
-sys.stdout.write(hash[0:8])
diff --git a/build_extra/rust/rust.gni b/build_extra/rust/rust.gni
index 586953917..1600602e0 100644
--- a/build_extra/rust/rust.gni
+++ b/build_extra/rust/rust.gni
@@ -120,8 +120,14 @@ template("run_rustc") {
     if (defined(crate_version)) {
       # Compute the sha256sum of the version number. See comments below.
       # Note that we do this only if there are multiple versions of this crate.
-      hash =
-          exec_script("get_version_hash.py", [ crate_version ], "trim string")
+      hash = exec_script("//tools/sha256sum.py",
+                         [
+                           "--input",
+                           crate_version,
+                           "--format",
+                           "%.8s",
+                         ],
+                         "trim string")
 
       args += [
         # In our build setup, all crates are built in the same directory. The
diff --git a/tools/sha256sum.py b/tools/sha256sum.py
new file mode 100644
index 000000000..d3273d5ba
--- /dev/null
+++ b/tools/sha256sum.py
@@ -0,0 +1,70 @@
+# Copyright 2018 the Deno authors. All rights reserved. MIT license.
+"""
+Computes the SHA256 hash and formats the result.
+"""
+
+import argparse
+from hashlib import sha256
+import os
+import sys
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+
+    # Arguments specifying where input comes from.
+    # If multiple sources are specified, they are all concatenated together.
+    parser.add_argument(
+        "--input",
+        action="append",
+        dest="input",
+        type=str,
+        metavar="TEXT",
+        help="Hash literal text specified on the command line.")
+    parser.add_argument(
+        "--infile",
+        action="append",
+        dest="input",
+        type=read_file,
+        metavar="FILE",
+        help="Hash the contents of a file.")
+
+    # Arguments dealing with output.
+    parser.add_argument(
+        "--format",
+        type=str,
+        dest="format",
+        default="%s",
+        metavar="TEMPLATE",
+        help="Format output using Python template (default = '%%s').")
+    parser.add_argument(
+        "--outfile",
+        dest="outfile",
+        type=argparse.FileType("wb"),
+        default=sys.stdout,
+        metavar="FILE",
+        help="Write the formatted hash to a file (default = stdout).")
+
+    # Parse arguments. Print usage and exit if given no input.
+    args = parser.parse_args()
+    if (not args.input):
+        parser.print_usage()
+        return 1
+
+    # Compute the hash of all inputs concatenated together.
+    hasher = sha256()
+    for data in args.input:
+        hasher.update(data)
+    hash = hasher.hexdigest()
+
+    # Format and write to specified out file (or the default, stdout).
+    args.outfile.write(args.format % hash)
+
+
+def read_file(filename):
+    with open(filename, "rb") as file:
+        return file.read()
+
+
+if __name__ == '__main__':
+    sys.exit(main())