GN hack to tag targets as poisonous (and use it with audio codecs)
Only specially taggged targets may transitively depend on poisonous
targets. We first apply it to audio codecs.
This makes it much clearer exactly what parts of the code still have
dependencies on the audio codecs (and we want to eventually get rid of
pretty much all of them).
Bug: webrtc:8396, webrtc:9121
Change-Id: Iba5c2e806c702b5cfe881022674705f647896d43
Reviewed-on: https://webrtc-review.googlesource.com/69520
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22979}diff --git a/webrtc.gni b/webrtc.gni
index cfc9cb0..b3f06ae 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -278,6 +278,41 @@
webrtc_default_visibility += [ webrtc_root + "/../webrtc_overrides/*" ]
}
+# ---- Poisons ----
+#
+# The general idea is that some targets declare that they contain some
+# kind of poison, which makes it impossible for other targets to
+# depend on them (even transitively) unless they declare themselves
+# immune to that particular type of poison.
+#
+# Targets that *contain* poison of type foo should contain the line
+#
+# poisonous = [ "foo" ]
+#
+# and targets that *are immune but arent't themselves poisonous*
+# should contain
+#
+# allow_poison = [ "foo" ]
+#
+# This useful in cases where we have some large target or set of
+# targets and want to ensure that most other targets do not
+# transitively depend on them. For example, almost no high-level
+# target should depend on the audio codecs, since we want WebRTC users
+# to be able to inject any subset of them and actually end up with a
+# binary that doesn't include the codecs they didn't inject.
+#
+# Test-only targets (`testonly` set to true) and non-public targets
+# (`visibility` not containing "*") are automatically immune to all
+# types of poison.
+#
+# Here's the complete list of all types of poison. It must be kept in
+# 1:1 correspondence with the set of //:poison_* targets.
+#
+all_poison_types = [
+ # Encoders and decoders for specific audio codecs such as Opus and iSAC.
+ "audio_codecs",
+]
+
template("rtc_test") {
test(target_name) {
forward_variables_from(invoker,
@@ -321,6 +356,45 @@
if (!defined(visibility)) {
visibility = webrtc_default_visibility
}
+
+ # What's your poison?
+ if (defined(testonly) && testonly) {
+ assert(!defined(poisonous))
+ assert(!defined(allow_poison))
+ } else {
+ if (!defined(poisonous)) {
+ poisonous = []
+ }
+ if (!defined(allow_poison)) {
+ allow_poison = []
+ }
+ if (!defined(assert_no_deps)) {
+ assert_no_deps = []
+ }
+ if (!defined(deps)) {
+ deps = []
+ }
+ foreach(p, poisonous) {
+ deps += [ webrtc_root + ":poison_" + p ]
+ }
+ foreach(poison_type, all_poison_types) {
+ allow_dep = true
+ foreach(v, visibility) {
+ if (v == "*") {
+ allow_dep = false
+ }
+ }
+ foreach(p, allow_poison + poisonous) {
+ if (p == poison_type) {
+ allow_dep = true
+ }
+ }
+ if (!allow_dep) {
+ assert_no_deps += [ webrtc_root + ":poison_" + poison_type ]
+ }
+ }
+ }
+
configs += invoker.configs
configs -= rtc_remove_configs
configs -= invoker.suppressed_configs
@@ -375,6 +449,45 @@
if (!defined(visibility)) {
visibility = webrtc_default_visibility
}
+
+ # What's your poison?
+ if (defined(testonly) && testonly) {
+ assert(!defined(poisonous))
+ assert(!defined(allow_poison))
+ } else {
+ if (!defined(poisonous)) {
+ poisonous = []
+ }
+ if (!defined(allow_poison)) {
+ allow_poison = []
+ }
+ if (!defined(assert_no_deps)) {
+ assert_no_deps = []
+ }
+ if (!defined(deps)) {
+ deps = []
+ }
+ foreach(p, poisonous) {
+ deps += [ webrtc_root + ":poison_" + p ]
+ }
+ foreach(poison_type, all_poison_types) {
+ allow_dep = true
+ foreach(v, visibility) {
+ if (v == "*") {
+ allow_dep = false
+ }
+ }
+ foreach(p, allow_poison + poisonous) {
+ if (p == poison_type) {
+ allow_dep = true
+ }
+ }
+ if (!allow_dep) {
+ assert_no_deps += [ webrtc_root + ":poison_" + poison_type ]
+ }
+ }
+ }
+
configs += invoker.configs
configs -= rtc_remove_configs
configs -= invoker.suppressed_configs
@@ -399,6 +512,45 @@
if (!defined(visibility)) {
visibility = webrtc_default_visibility
}
+
+ # What's your poison?
+ if (defined(testonly) && testonly) {
+ assert(!defined(poisonous))
+ assert(!defined(allow_poison))
+ } else {
+ if (!defined(poisonous)) {
+ poisonous = []
+ }
+ if (!defined(allow_poison)) {
+ allow_poison = []
+ }
+ if (!defined(assert_no_deps)) {
+ assert_no_deps = []
+ }
+ if (!defined(deps)) {
+ deps = []
+ }
+ foreach(p, poisonous) {
+ deps += [ webrtc_root + ":poison_" + p ]
+ }
+ foreach(poison_type, all_poison_types) {
+ allow_dep = true
+ foreach(v, visibility) {
+ if (v == "*") {
+ allow_dep = false
+ }
+ }
+ foreach(p, allow_poison + poisonous) {
+ if (p == poison_type) {
+ allow_dep = true
+ }
+ }
+ if (!allow_dep) {
+ assert_no_deps += [ webrtc_root + ":poison_" + poison_type ]
+ }
+ }
+ }
+
configs += invoker.configs
configs -= rtc_remove_configs
configs -= invoker.suppressed_configs
