Switch to api.ast.json.gz instead of api.ast.json

api.ast.json consumes 2.5GB in the output directory, compressing it
saves 2.4GB of storage. The saving is useful in devhouse and for
github actions (linux SSD size 14GB).

Test: build bazel //... && bazel test //...

build/cc_ast_dump.bzl

@@ -37,7 +37,7 @@ def _cc_ast_dump_impl(ctx):
     inputs = depset(direct = [ctx.file.src], transitive = [cc_toolchain.all_files] + [cc_info.compilation_context.headers])
     env = cc_common.get_environment_variables(feature_configuration = feature_configuration, action_name = CPP_COMPILE_ACTION_NAME, variables = variables)
 
-    command = " ".join([executable] + arguments + [">", ctx.outputs.out.path])
+    command = " ".join([executable] + arguments + ["|", "gzip", "-3", "-", ">", ctx.outputs.out.path])
 
     # run_shell until https://github.com/bazelbuild/bazel/issues/5511 is fixed
     ctx.actions.run_shell(

rust-deps/BUILD.bazel

@@ -108,6 +108,9 @@ crates_vendor(
         "clang-ast": crate.spec(
             version = "0.1",
         ),
+        "flate2": crate.spec(
+            version = "1.0.24",
+        ),
         "serde": crate.spec(
             version = "1.0",
             features = ["default", "derive"],

rust-deps/crates/BUILD.bazel

@@ -57,6 +57,12 @@ alias(
     tags = ["manual"],
 )
 
+alias(
+    name = "flate2",
+    actual = "@crates_vendor__flate2-1.0.24//:flate2",
+    tags = ["manual"],
+)
+
 alias(
     name = "libc",
     actual = "@crates_vendor__libc-0.2.137//:libc",

src/workerd/tools/BUILD.bazel

@@ -89,7 +89,7 @@ filegroup(
 cc_ast_dump(
     name = "dump_api_ast",
     src = api_encoder_src,
-    out = "api.ast.json",
+    out = "api.ast.json.gz",
     deps = [":api_encoder_lib"],
 )
 
@@ -99,6 +99,7 @@ rust_binary(
     deps = [
         "@crates_vendor//:anyhow",
         "@crates_vendor//:clang-ast",
+        "@crates_vendor//:flate2",
         "@crates_vendor//:pico-args",
         "@crates_vendor//:serde",
         "@crates_vendor//:serde_json",

src/workerd/tools/param-extractor.rs

@@ -1,9 +1,12 @@
 use std::{
+    ffi::OsStr,
     fs::File,
     io::{BufReader, BufWriter, Write},
+    path::Path,
 };
 
 use anyhow::Result;
+use flate2::read::GzDecoder;
 use serde::{Deserialize, Serialize};
 
 /// Contains the declarations we care about
@@ -50,10 +53,14 @@ type ClangNode = clang_ast::Node<Clang>;
 fn main() -> Result<()> {
     let mut args = pico_args::Arguments::from_env();
 
-    let clang_ast = args.value_from_os_str("--input", |path| {
+    let clang_ast = args.value_from_os_str("--input", |path_str| {
+        let path = Path::new(path_str);
         let file = File::open(path)?;
-        let rdr = BufReader::new(file);
-        serde_json::from_reader(rdr).map_err(anyhow::Error::from)
+        let serde = match path.extension().and_then(OsStr::to_str) {
+            Some("gz") => serde_json::from_reader(BufReader::new(GzDecoder::new(file))),
+            _ => serde_json::from_reader(BufReader::new(file))
+        };
+        serde.map_err(anyhow::Error::from)
     })?;
 
     let value = get_parameter_names(clang_ast);