Add --version flag

bazel/version_h.bzl

@@ -0,0 +1,31 @@
+load("@bazel_skylib//rules:common_settings.bzl", "BuildSettingInfo")
+
+def _version_h_impl(ctx):
+    guard = "{}_{}_H_INCLUDED".format(ctx.label.name.upper(), ctx.attr.varname)
+    content = [
+        "#ifndef {}".format(guard),
+        "#define {} \"{}\"".format(ctx.attr.varname, ctx.attr.version[BuildSettingInfo].value),
+        "#endif {}".format(guard),
+    ]
+    ctx.actions.write(
+        output = ctx.outputs.out,
+        content = "\n".join(content),
+    )
+    files = depset(direct = [ctx.outputs.out])
+    runfiles = ctx.runfiles(files = [ctx.outputs.out])
+    return [DefaultInfo(files = files, data_runfiles = runfiles)]
+
+version_h = rule(
+    implementation = _version_h_impl,
+    output_to_genfiles = True,
+    attrs = {
+        "out": attr.output(mandatory = True),
+        "varname": attr.string(
+            doc = "Name of the varible to hold the versions",
+        ),
+        "version": attr.label(
+            doc = "Version of this build.",
+        ),
+    },
+    doc = "Version as C/C++ header file.",
+)

bcc/BUILD

@@ -1,11 +1,14 @@
+load("@//bazel:version_h.bzl", "version_h")
 load("@bazel_skylib//rules:copy_file.bzl", "copy_file")
 load("@build_bazel_apple_support//rules:universal_binary.bzl", "universal_binary")
 
 package(default_visibility = ["//visibility:public"])
 
 cc_binary(
     name = "bazel-compile-commands-binary",
-    srcs = ["main.cpp"],
+    srcs = [
+        "main.cpp",
+    ],
     linkopts = select({
         "@platforms//os:windows": ["-DEFAULTLIB:shell32.lib"],
         "//conditions:default": [],
@@ -108,7 +111,10 @@ cc_library(
 cc_library(
     name = "options",
     srcs = ["options.cpp"],
-    hdrs = ["options.hpp"],
+    hdrs = [
+        "options.hpp",
+        ":version",
+    ],
     defines = ["BOOST_PROCESS_USE_STD_FS=1"],
     deps = [
         "@boost//:process",
@@ -142,6 +148,13 @@ cc_library(
     hdrs = ["replacements.hpp"],
 )
 
+version_h(
+    name = "version",
+    out = "version.h",
+    varname = "BCC_VERSION",
+    version = "//:version",
+)
+
 cc_test(
     name = "replacements_test",
     size = "small",

bcc/options.cpp

@@ -1,4 +1,5 @@
 #include "bcc/options.hpp"
+#include "bcc/version.h"
 
 #include <cstdlib>
 #include <fstream>
@@ -49,6 +50,7 @@ options::from_argv(int argc, char* argv[])
   // clang-format off
   cfg.add_options()
     ("help,h", "produce help message")
+    ("version,V", "print version")
     ("verbose,v", po::bool_switch(&result.verbose), "verbose, report more information")
     ("arguments,a", po::bool_switch(&result.arguments), "include `arguments` array in output")
     ("resolve", po::bool_switch(&result.resolve), "resolve file symlinks when their target is inside the workspace")
@@ -92,6 +94,10 @@ options::from_argv(int argc, char* argv[])
     std::cerr << desc << '\n';
     std::exit(0);
   }
+  if (vm.count("version")) {
+    std::cerr << BCC_VERSION << '\n';
+    std::exit(0);
+  }
 
   if (vm.count("compiler")) {
     result.compiler = vm["compiler"].as<std::string>();