build: Add an install target.

Adds a bazel rule that mimics the GNU Makefile standard.

https://www.gnu.org/prep/standards/html_node/Standard-Targets.html

BUILD

@@ -1,4 +1,5 @@
 load("@buildifier_prebuilt//:rules.bzl", "buildifier")
+load("//:install.bzl", "install")
 load("//:subst.bzl", "subst_template")
 
 package(default_visibility = [":__subpackages__"])
@@ -67,15 +68,16 @@ cc_binary(
 )
 
 SUBSTITUTIONS = {
-    "@sysconfdir@": "/etc",
-    "@pkgexdir@": "/usr/share/doc/filergen/examples",
+    "@sysconfdir@": "/etc/filtergen",
+    "@pkgexdir@": "/usr/share/doc/filtergen/examples",
     "@sbindir@": "/usr/sbin",
     "@VERSION@": VERSION,
 }
 
 subst_template(
     name = "fgadm",
     src = "fgadm.in",
+    executable = True,
     substitutions = SUBSTITUTIONS,
 )
 
@@ -97,6 +99,23 @@ subst_template(
     substitutions = SUBSTITUTIONS,
 )
 
+install(
+    name = "install",
+    prefix = "/home/jaq/fgbin",
+    targets = {
+        ":fgadm": "/sbin",
+        ":filtergen": "/sbin",
+        ":fgadm.conf": "/etc/filtergen",
+        ":rules.filter": "/etc/filtergen",
+        "filter_syntax.5": "/man/man5",
+        "filter_backends.7": "/man/man7",
+        "filtergen.8": "/man/man8",
+        "fgadm.8": "/man/man8",
+        "//examples:examples": "/doc/filtergen/examples",
+        "//doc:doc": "/doc/filtergen",
+    },
+)
+
 buildifier(
     name = "buildifier",
     exclude_patterns = [

doc/BUILD

@@ -0,0 +1,8 @@
+filegroup(
+    name = "doc",
+    srcs = glob(
+        ["*"],
+        exclude = ["BUILD"],
+    ),
+    visibility = ["//:__pkg__"],
+)

examples/BUILD

@@ -1,5 +1,8 @@
 filegroup(
     name = "examples",
     srcs = glob(["*.filter"]),
-    visibility = ["//testsuite/filtergen:__pkg__"],
+    visibility = [
+        "//:__pkg__",
+        "//testsuite/filtergen:__pkg__",
+    ],
 )

install.bzl

@@ -0,0 +1,78 @@
+"""Install rules.
+
+Based on the GNU Makefile standard targets: https://www.gnu.org/prep/standards/html_node/Standard-Targets.html
+"""
+
+def _install_impl(ctx):
+    """Install some targets somewhere in the filesystem."""
+
+    # Like https://www.gnu.org/prep/standards/html_node/DESTDIR.html#DESTDIR
+    output = ctx.actions.declare_file("install_script")
+    commands = "#!/usr/bin/env bash\nexport RUNFILES_LIB_DEBUG=1\ncat $0\n" + RUNFILES_BOILERPLATE
+    runfiles = ctx.runfiles(files = [ctx.file._bash_runfile_helper])
+    for target in ctx.attr.targets:
+        print(target)
+        target_dir = ctx.attr.prefix + ctx.attr.targets.get(target)
+        commands += "install -d {}\n".format(target_dir)
+        mode = "-m 644"
+
+        # Like https://www.gnu.org/prep/standards/html_node/Command-Variables.html#Command-Variables
+        if target[DefaultInfo].files_to_run and target[DefaultInfo].files_to_run.executable:
+            mode = ""
+        print(target, target[DefaultInfo].files.to_list())
+        installables = ["$(rlocation _main/{})".format(x.short_path) for x in target[DefaultInfo].files.to_list()]
+        commands += "install {mode} {target} {dest}\n".format(mode = mode, target = " ".join(installables), dest = target_dir)
+        runfiles = runfiles.merge_all([
+            target[DefaultInfo].default_runfiles,
+            ctx.runfiles(target[DefaultInfo].files.to_list()),
+        ])
+    ctx.actions.write(
+        output = output,
+        is_executable = True,
+        content = commands,
+    )
+    return [
+        DefaultInfo(
+            executable = output,
+            runfiles = runfiles,
+        ),
+    ]
+
+RUNFILES_BOILERPLATE = """
+# --- begin runfiles.bash initialization v3 ---
+# Copy-pasted from the Bazel Bash runfiles library v3.
+set -uo pipefail; set +e; f=bazel_tools/tools/bash/runfiles/runfiles.bash
+source "${RUNFILES_DIR:-/dev/null}/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "${RUNFILES_MANIFEST_FILE:-/dev/null}" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$0.runfiles/$f" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  source "$(grep -sm1 "^$f " "$0.exe.runfiles_manifest" | cut -f2- -d' ')" 2>/dev/null || \
+  { echo>&2 "ERROR: cannot find $f"; exit 1; }; f=; set -e
+# --- end runfiles.bash initialization v3 ---
+"""
+
+install = rule(
+    implementation = _install_impl,
+    doc = "Install some targets to the filesystem.",
+    attrs = {
+        "srcs": attr.label_list(
+            allow_files = True,
+        ),
+        "prefix": attr.string(
+            default = "/usr/local",
+            doc = "Installation prefix directory, aka DESTDIR.",
+        ),
+        "targets": attr.label_keyed_string_dict(
+            doc = "Installation targets of label:destination",
+            allow_files = True,
+        ),
+        # Bazel ships with a useful bash function for querying the absolute path to runfiles at
+        # runtime.
+        "_bash_runfile_helper": attr.label(
+            default = "@bazel_tools//tools/bash/runfiles",
+            doc = "Label pointing to bash runfile helper",
+            allow_single_file = True,
+        ),
+    },
+    executable = True,
+)

subst.bzl

@@ -8,9 +8,22 @@ def _subst_template_impl(ctx):
         output = output,
         substitutions = ctx.attr.substitutions,
     )
-    return [
-        DefaultInfo(files = depset([output])),
-    ]
+    runfiles = ctx.runfiles(files = [output])
+    files = depset([output])
+    if ctx.attr.executable:
+        return [
+            DefaultInfo(
+                executable = output,
+                runfiles = runfiles,
+            ),
+        ]
+    else:
+        return [
+            DefaultInfo(
+                files = files,
+                runfiles = runfiles,
+            ),
+        ]
 
 subst_template = rule(
     implementation = _subst_template_impl,
@@ -23,5 +36,9 @@ subst_template = rule(
         "substitutions": attr.string_dict(
             doc = "Substitutions to apply to the template",
         ),
+        "executable": attr.bool(
+            default = False,
+            doc = "Set if the substitution is an executable.",
+        ),
     },
 )