Minimize default MIME map and optimize loading.ndk-sysroot-r21

This CL topic speeds up DefaultMimeMapFactory.create() from 15.5msec
to 5.7msec (measured by bundling a copy of the logic and data into
a test app) and saves 5.2 KByte of space (16 KBytes uncompressed) in
framework.jar. This CL topic does not change the amount of heap memory
consumed by the loaded MimeMap.

This achieved by moving parsing steps from DefaultMimeMapFactory
into a build-time optimization step. This particular CL adds this
logic for debian.mime.types; see the companion CL in frameworks/base
for a more in-depth explanation.

Test: Checked that the mapping didn't change by checking that
      a device flashed after this CL passes CtsMimeMapTestCases
      built before this CL.
Test: Ran "make mimemap-res.jar" and manually verified that files
      in the resulting jar look as expected.
Test: Locally added some extra mappings to vendor.mime.types, some
      of them with a leading '?', and verified that they all show
      up with exactly one leading '?' for the MIME type and each
      extension within mimemap-res.jar.
Bug: 142267887

Change-Id: I63fb4c8776e70907baf6fd2c41b74b1338f06032

1 files changed, 5 insertions, 3 deletions

diff --git a/Android.bp b/Android.bp
index d08cd6f..33fad46 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,10 +1,12 @@
-filegroup {
-    name: "debian.mime.types",
+java_genrule {
+    name: "debian.mime.types.minimized",
     visibility: [
         "//visibility:public",
     ],
-    path: "",
+    out: ["debian.mime.types"],
     srcs: [
         "mime.types",
     ],
+    //    strip comments            normalize whitepace       drop empty lines
+    cmd: "awk '{gsub(/#.*$$/,\"\"); $$1=$$1; print;}' $(in) | grep ' ' > $(out)",
 }