1 files changed, 171 insertions, 0 deletions
diff --git a/tools/lint/rust/__init__.py b/tools/lint/rust/__init__.py
new file mode 100644
index 0000000000..60135adcab
--- /dev/null
+++ b/tools/lint/rust/__init__.py
@@ -0,0 +1,171 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import os
+import signal
+import six
+import re
+import subprocess
+from collections import namedtuple
+from distutils.version import StrictVersion
+
+from mozfile import which
+from mozlint import result
+from mozlint.pathutils import expand_exclusions
+from mozprocess import ProcessHandler
+
+
+RUSTFMT_NOT_FOUND = """
+Could not find rustfmt! Install rustfmt and try again.
+
+    $ rustup component add rustfmt
+
+And make sure that it is in the PATH
+""".strip()
+
+
+RUSTFMT_INSTALL_ERROR = """
+Unable to install correct version of rustfmt
+Try to install it manually with:
+    $ rustup component add rustfmt
+""".strip()
+
+
+RUSTFMT_WRONG_VERSION = """
+You are probably using an old version of rustfmt.
+Expected version is {version}.
+Try to update it:
+    $ rustup update stable
+""".strip()
+
+
+def parse_issues(config, output, paths):
+    RustfmtDiff = namedtuple("RustfmtDiff", ["file", "line", "diff"])
+    issues = []
+    diff_line = re.compile("^Diff in (.*) at line ([0-9]*):")
+    file = ""
+    line_no = 0
+    diff = ""
+    for line in output:
+        line = six.ensure_text(line)
+        match = diff_line.match(line)
+        if match:
+            if diff:
+                issues.append(RustfmtDiff(file, line_no, diff.rstrip("\n")))
+                diff = ""
+            file, line_no = match.groups()
+        else:
+            diff += line + "\n"
+    # the algorithm above will always skip adding the last issue
+    issues.append(RustfmtDiff(file, line_no, diff))
+    results = []
+    for issue in issues:
+        # rustfmt can not be supplied the paths to the files we want to analyze
+        # therefore, for each issue detected, we check if any of the the paths
+        # supplied are part of the file name.
+        # This just filters out the issues that are not part of paths.
+        if any([path in file for path in paths]):
+            res = {
+                "path": issue.file,
+                "diff": issue.diff,
+                "level": "warning",
+                "lineno": issue.line,
+            }
+            results.append(result.from_config(config, **res))
+    return results
+
+
+class RustfmtProcess(ProcessHandler):
+    def __init__(self, config, *args, **kwargs):
+        self.config = config
+        kwargs["stream"] = False
+        ProcessHandler.__init__(self, *args, **kwargs)
+
+    def run(self, *args, **kwargs):
+        orig = signal.signal(signal.SIGINT, signal.SIG_IGN)
+        ProcessHandler.run(self, *args, **kwargs)
+        signal.signal(signal.SIGINT, orig)
+
+
+def run_process(config, cmd):
+    proc = RustfmtProcess(config, cmd)
+    proc.run()
+    try:
+        proc.wait()
+    except KeyboardInterrupt:
+        proc.kill()
+
+    return proc.output
+
+
+def get_rustfmt_binary():
+    """
+    Returns the path of the first rustfmt binary available
+    if not found returns None
+    """
+    binary = os.environ.get("RUSTFMT")
+    if binary:
+        return binary
+
+    return which("rustfmt")
+
+
+def get_rustfmt_version(binary):
+    """
+    Returns found binary's version
+    """
+    try:
+        output = subprocess.check_output(
+            [binary, "--version"],
+            stderr=subprocess.STDOUT,
+            universal_newlines=True,
+        )
+    except subprocess.CalledProcessError as e:
+        output = e.output
+
+    version = re.findall(r"\d.\d+.\d+", output)[0]
+    return StrictVersion(version)
+
+
+def lint(paths, config, fix=None, **lintargs):
+    log = lintargs["log"]
+    paths = list(expand_exclusions(paths, config, lintargs["root"]))
+
+    # An empty path array can occur when the user passes in `-n`. If we don't
+    # return early in this case, rustfmt will attempt to read stdin and hang.
+    if not paths:
+        return []
+
+    binary = get_rustfmt_binary()
+
+    if not binary:
+        print(RUSTFMT_NOT_FOUND)
+        if "MOZ_AUTOMATION" in os.environ:
+            return 1
+        return []
+
+    min_version_str = config.get("min_rustfmt_version")
+    min_version = StrictVersion(min_version_str)
+    actual_version = get_rustfmt_version(binary)
+    log.debug(
+        "Found version: {}. Minimal expected version: {}".format(
+            actual_version, min_version
+        )
+    )
+
+    if actual_version < min_version:
+        print(RUSTFMT_WRONG_VERSION.format(version=min_version_str))
+        return 1
+
+    cmd_args = [binary]
+    if not fix:
+        cmd_args.append("--check")
+    base_command = cmd_args + paths
+    log.debug("Command: {}".format(" ".join(cmd_args)))
+    output = run_process(config, base_command)
+
+    if fix:
+        # Rustfmt is able to fix all issues so don't bother parsing the output.
+        return []
+    return parse_issues(config, output, paths)