Bug 1466070 - Integrate clang-format into mozlint r=linter-reviewers,ahal

For now, the local detection sucks. I will fix that once bug 1625884
is fixed

Differential Revision: https://phabricator.services.mozilla.com/D69683

--HG--
extra : moz-landing-system : lando

.clang-format-ignore

@@ -59,6 +59,9 @@ tools/clang-tidy/test/.*
 # We are testing the incorrect formatting.
 tools/lint/test/files/file-whitespace/
 
+# Test reformatting
+tools/lint/test/files/clang-format/
+
 # Contains an XML definition and formatting would break the layout
 widget/gtk/MPRISInterfaceDescription.h
 

docs/code-quality/lint/linters/clang-format.rst

@@ -0,0 +1,35 @@
+clang-format
+============
+
+`clang-format <https://clang.llvm.org/docs/ClangFormat.html>`__ is a tool to reformat C/C++ to the right coding style.
+
+Run Locally
+-----------
+
+The mozlint integration of clang-format can be run using mach:
+
+.. parsed-literal::
+
+    $ mach lint --linter clang-format <file paths>
+
+
+Configuration
+-------------
+
+To enable clang-format on new directory, add the path to the include
+section in the `clang-format.yml <https://searchfox.org/mozilla-central/source/tools/lint/clang-format.yml>`_ file.
+
+While excludes: will work, this linter will read the ignore list from `.clang-format-ignore file <https://searchfox.org/mozilla-central/source/.clang-format-ignore>`_
+at the root directory. This because it is also used by the ./mach clang-format -p command.
+
+Autofix
+-------
+
+clang-format can reformat the code with the option `--fix` (based on the upstream option `-i`).
+To highlight the results, we are using the ``--dry-run`` option (from clang-format 10).
+
+Sources
+-------
+
+* `Configuration (YAML) <https://searchfox.org/mozilla-central/source/tools/lint/clang-format.yml>`_
+* `Source <https://searchfox.org/mozilla-central/source/tools/lint/clang-format/__init__.py>`_

tools/lint/clang-format.yml

@@ -0,0 +1,11 @@
+---
+clang-format:
+    description: Reformat C/C++
+    include:
+        - '.'
+    extensions: ['cpp', 'c', 'cc', 'h', 'm', 'mm']
+    support-files:
+        - 'tools/lint/clang-format/**'
+    type: external
+    payload: clang-format:lint
+    code_review_warnings: true

tools/lint/clang-format/__init__.py

@@ -0,0 +1,166 @@
+# 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 re
+
+from buildconfig import substs
+from mozboot.util import get_state_dir
+from mozlint import result
+from mozlint.pathutils import expand_exclusions
+from mozprocess import ProcessHandler
+
+CLANG_FORMAT_NOT_FOUND = """
+Could not find clang-format! Install clang-format with:
+
+    $ ./mach bootstrap
+
+And make sure that it is in the PATH
+""".strip()
+
+
+def parse_issues(config, output, paths, log):
+
+    diff_line = re.compile("^(.*):(.*):(.*): warning: .*;(.*);(.*)")
+    results = []
+    for line in output:
+        match = diff_line.match(line)
+        file, line_no, col, diff, diff2 = match.groups()
+        log.debug("file={} line={} col={} diff={} diff2={}".format(
+            file, line_no, col, diff, diff2))
+        d = diff + "\n" + diff2
+        res = {
+            "path": file,
+            "diff": d,
+            "level": "warning",
+            "lineno": line_no,
+            "column": col,
+        }
+        results.append(result.from_config(config, **res))
+
+    return results
+
+
+class ClangFormatProcess(ProcessHandler):
+    def __init__(self, config, *args, **kwargs):
+        self.config = config
+        kwargs["stream"] = False
+        kwargs["universal_newlines"] = True
+        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 = ClangFormatProcess(config, cmd)
+    proc.run()
+    try:
+        proc.wait()
+    except KeyboardInterrupt:
+        proc.kill()
+
+    return proc.output
+
+
+def get_clang_format_binary():
+    """
+    Returns the path of the first clang-format binary available
+    if not found returns None
+    """
+    binary = os.environ.get("CLANG_FORMAT")
+    if binary:
+        return binary
+
+    clang_tools_path = os.path.join(get_state_dir(), "clang-tools")
+    bin_path = os.path.join(clang_tools_path, "clang-tidy", "bin")
+    return os.path.join(bin_path, "clang-format" + substs.get('BIN_SUFFIX', ''))
+
+
+def is_ignored_path(ignored_dir_re, topsrcdir, f):
+    # Remove up to topsrcdir in pathname and match
+    if f.startswith(topsrcdir + '/'):
+        match_f = f[len(topsrcdir + '/'):]
+    else:
+        match_f = f
+    return re.match(ignored_dir_re, match_f)
+
+
+def remove_ignored_path(paths, topsrcdir, log):
+    path_to_third_party = os.path.join(topsrcdir, '.clang-format-ignore')
+
+    ignored_dir = []
+    with open(path_to_third_party, 'r') as fh:
+        for line in fh:
+            # In case it starts with a space
+            line = line.strip()
+            # Remove comments and empty lines
+            if line.startswith('#') or len(line) == 0:
+                continue
+            # The regexp is to make sure we are managing relative paths
+            ignored_dir.append(r"^[\./]*" + line.rstrip())
+
+    # Generates the list of regexp
+    ignored_dir_re = '(%s)' % '|'.join(ignored_dir)
+
+    path_list = []
+    for f in paths:
+        if is_ignored_path(ignored_dir_re, topsrcdir, f):
+            # Early exit if we have provided an ignored directory
+            log.debug("Ignored third party code '{0}'".format(f))
+            continue
+        path_list.append(f)
+
+    return path_list
+
+
+def lint(paths, config, fix=None, **lintargs):
+    log = lintargs['log']
+    paths = list(expand_exclusions(paths, config, lintargs['root']))
+
+    # We ignored some specific files for a bunch of reasons.
+    # Not using excluding to avoid duplication
+    if lintargs.get('use_filters', True):
+        paths = remove_ignored_path(paths, lintargs['root'], log)
+
+    # 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_clang_format_binary()
+
+    if not binary:
+        print(CLANG_FORMAT_NOT_FOUND)
+        if "MOZ_AUTOMATION" in os.environ:
+            return 1
+        return []
+
+    cmd_args = [binary]
+    if fix:
+        cmd_args.append("-i")
+    else:
+        cmd_args.append("--dry-run")
+    base_command = cmd_args + paths
+    log.debug("Command: {}".format(' '.join(cmd_args)))
+    output = run_process(config, base_command)
+    output_list = []
+
+    if len(output) % 3 != 0:
+        raise Exception("clang-format output should be a multiple of 3. Output: %s" % output)
+
+    for i in range(0, len(output), 3):
+        # Merge the element 3 by 3 (clang-format output)
+        line = output[i]
+        line += ";" + output[i+1]
+        line += ";" + output[i+2]
+        output_list.append(line)
+
+    if fix:
+        # clang-format is able to fix all issues so don't bother parsing the output.
+        return []
+    return parse_issues(config, output_list, paths, log)

tools/lint/test/files/clang-format/bad/bad.cpp

@@ -0,0 +1,6 @@
+int  main ( ) { 
+
+return 0;   
+
+
+}

tools/lint/test/files/clang-format/bad/bad2.c

@@ -0,0 +1,8 @@
+#include "bad2.h"
+
+
+int bad2() {
+  int a =2;
+  return a;
+
+}

tools/lint/test/files/clang-format/bad/bad2.h

@@ -0,0 +1 @@
+int bad2(void );

tools/lint/test/files/clang-format/bad/good.cpp

@@ -0,0 +1 @@
+int main() { return 0; }

tools/lint/test/files/clang-format/good/foo.cpp

@@ -0,0 +1 @@
+int main() { return 0; }

tools/lint/test/python.ini

@@ -22,3 +22,5 @@ skip-if = os == "win" || os == "mac"  # fails with No module named 'pkg_resource
 skip-if = os == "win" || os == "mac"  # only installed on Linux
 [test_rustfmt.py]
 skip-if = os == "win" || os == "mac"  # only installed on Linux
+[test_clang_format.py]
+skip-if = os == "win" || os == "mac"  # only installed on Linux

tools/lint/test/test_clang_format.py

@@ -0,0 +1,48 @@
+import mozunit
+
+from conftest import build
+
+LINTER = 'clang-format'
+
+
+def test_good(lint, config, paths):
+    results = lint(paths("good/"), root=build.topsrcdir, use_filters=False)
+    print(results)
+    assert len(results) == 0
+
+
+def test_basic(lint, config, paths):
+    results = lint(paths("bad/bad.cpp"), root=build.topsrcdir, use_filters=False)
+    print(results)
+    assert len(results) >= 1
+
+    assert "Reformat C/C++" in results[0].message
+    assert results[0].level == "warning"
+    assert results[0].lineno == 1
+    assert results[0].column == 4
+    assert "bad.cpp" in results[0].path
+    assert 'int  main ( ) {' in results[0].diff
+
+
+def test_dir(lint, config, paths):
+    results = lint(paths("bad/"), root=build.topsrcdir, use_filters=False)
+    print(results)
+    assert len(results) >= 4
+
+    assert "Reformat C/C++" in results[0].message
+    assert results[0].level == "warning"
+    assert results[0].lineno == 1
+    assert results[0].column == 4
+    assert "bad.cpp" in results[0].path
+    assert 'int  main ( ) {' in results[0].diff
+
+    assert "Reformat C/C++" in results[5].message
+    assert results[5].level == "warning"
+    assert results[5].lineno == 1
+    assert results[5].column == 18
+    assert "bad2.c" in results[5].path
+    assert "#include" in results[5].diff
+
+
+if __name__ == '__main__':
+    mozunit.main()