commit 7d53f19089829409075d8ad3dbf3447e80f0f2ac
author Ryan Mitchell <rtmitchell@google.com> Fri Apr 24 17:45:25 2020 -0700
committer Ryan Mitchell <rtmitchell@google.com> Tue Apr 28 18:07:00 2020 +0000
tree 756901a0bfb3e27e5c46a240f5fd647d601865ae
parent ac774e3304d1c52d1f9057aabaa39bcb1249c656

Reduce OMS start time

This change attempts to reduce the amount of time initializing the
OMS. The change:
1) Reduces the amount of time between subsequent attempts to connect
   to the idmap2d service when it is not alive.
2) Caches package infos retrieved from getOverlayPackages
3) Caches the crc of the android package to preventing having to
   retrieve it for every overlay package targeting the framework

This chance reduced OMS start up time from ~500ms to ~100ms on a
Pixel 3. If the idmap2d service is running when system sever starts
then start up time will be around ~70ms.

Bug: 151481016
Test: adb shell stop && adb shell start && [capture trace]

Change-Id: I6137c385baf099413b62e98557419fffb9fd2d93

cmds/idmap2/libidmap2/Idmap.cpp

diff --git a/cmds/idmap2/libidmap2/Idmap.cpp b/cmds/idmap2/libidmap2/Idmap.cpp
index 7f2cd959..706b842 100644
--- a/cmds/idmap2/libidmap2/Idmap.cpp
+++ b/cmds/idmap2/libidmap2/Idmap.cpp
@@ -100,7 +100,9 @@
   return buf;
 }
 
-Result<uint32_t> GetCrc(const ZipFile& zip) {
+}  // namespace
+
+Result<uint32_t> GetPackageCrc(const ZipFile& zip) {
   const Result<uint32_t> a = zip.Crc("resources.arsc");
   const Result<uint32_t> b = zip.Crc("AndroidManifest.xml");
   return a && b
@@ -108,8 +110,6 @@
              : Error("failed to get CRC for \"%s\"", a ? "AndroidManifest.xml" : "resources.arsc");
 }
 
-}  // namespace
-
 std::unique_ptr<const IdmapHeader> IdmapHeader::FromBinaryStream(std::istream& stream) {
   std::unique_ptr<IdmapHeader> idmap_header(new IdmapHeader());
 
@@ -130,6 +130,20 @@
 }
 
 Result<Unit> IdmapHeader::IsUpToDate() const {
+  const std::unique_ptr<const ZipFile> target_zip = ZipFile::Open(target_path_);
+  if (!target_zip) {
+    return Error("failed to open target %s", GetTargetPath().to_string().c_str());
+  }
+
+  Result<uint32_t> target_crc = GetPackageCrc(*target_zip);
+  if (!target_crc) {
+    return Error("failed to get target crc");
+  }
+
+  return IsUpToDate(*target_crc);
+}
+
+Result<Unit> IdmapHeader::IsUpToDate(uint32_t target_crc) const {
   if (magic_ != kIdmapMagic) {
     return Error("bad magic: actual 0x%08x, expected 0x%08x", magic_, kIdmapMagic);
   }
@@ -138,19 +152,9 @@
     return Error("bad version: actual 0x%08x, expected 0x%08x", version_, kIdmapCurrentVersion);
   }
 
-  const std::unique_ptr<const ZipFile> target_zip = ZipFile::Open(target_path_);
-  if (!target_zip) {
-    return Error("failed to open target %s", GetTargetPath().to_string().c_str());
-  }
-
-  Result<uint32_t> target_crc = GetCrc(*target_zip);
-  if (!target_crc) {
-    return Error("failed to get target crc");
-  }
-
-  if (target_crc_ != *target_crc) {
+  if (target_crc_ != target_crc) {
     return Error("bad target crc: idmap version 0x%08x, file system version 0x%08x", target_crc_,
-                 *target_crc);
+                 target_crc);
   }
 
   const std::unique_ptr<const ZipFile> overlay_zip = ZipFile::Open(overlay_path_);
@@ -158,7 +162,7 @@
     return Error("failed to open overlay %s", GetOverlayPath().to_string().c_str());
   }
 
-  Result<uint32_t> overlay_crc = GetCrc(*overlay_zip);
+  Result<uint32_t> overlay_crc = GetPackageCrc(*overlay_zip);
   if (!overlay_crc) {
     return Error("failed to get overlay crc");
   }
@@ -304,13 +308,13 @@
   header->magic_ = kIdmapMagic;
   header->version_ = kIdmapCurrentVersion;
 
-  Result<uint32_t> crc = GetCrc(*target_zip);
+  Result<uint32_t> crc = GetPackageCrc(*target_zip);
   if (!crc) {
     return Error(crc.GetError(), "failed to get zip CRC for target");
   }
   header->target_crc_ = *crc;
 
-  crc = GetCrc(*overlay_zip);
+  crc = GetPackageCrc(*overlay_zip);
   if (!crc) {
     return Error(crc.GetError(), "failed to get zip CRC for overlay");
   }