Add "warm" starting to mobile-install.

This introduces a new way to stop applications when deploying incremental
changes that saves the current app state for the next run. This allows things
like the back stack, and View/Fragment/Activity saved state to be restored when
the app next launches, making it easier to quickly iterate on code changes.

It adds a "--start" flag to mobile-install that replaces "--start_app".
--start accepts an argument describing the mode: no, cold, or warm. "no" is
now the equivalent of "--nostart_app", "cold" is the equivalent of
"--start_app", and "warm" is the new start mode.

Note that this is only useful with incremental installs, as Android clears out
any previously saved state when an APK is replaced.

--
MOS_MIGRATED_REVID=99508790

1 files changed, 9 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/runtime/commands/MobileInstallCommand.java b/src/main/java/com/google/devtools/build/lib/runtime/commands/MobileInstallCommand.java
index b68adb859e..13e2837dff 100644
--- a/src/main/java/com/google/devtools/build/lib/runtime/commands/MobileInstallCommand.java
+++ b/src/main/java/com/google/devtools/build/lib/runtime/commands/MobileInstallCommand.java
@@ -16,7 +16,9 @@ package com.google.devtools.build.lib.runtime.commands;
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.analysis.OutputGroupProvider;
 import com.google.devtools.build.lib.buildtool.BuildRequest;
+import com.google.devtools.build.lib.events.Event;
 import com.google.devtools.build.lib.rules.android.WriteAdbArgsAction;
+import com.google.devtools.build.lib.rules.android.WriteAdbArgsAction.StartType;
 import com.google.devtools.build.lib.runtime.BlazeCommand;
 import com.google.devtools.build.lib.runtime.BlazeRuntime;
 import com.google.devtools.build.lib.runtime.Command;
@@ -64,6 +66,13 @@ public class MobileInstallCommand implements BlazeCommand {
 
   @Override
   public ExitCode exec(BlazeRuntime runtime, OptionsProvider options) {
+    Options mobileInstallOptions = options.getOptions(Options.class);
+    WriteAdbArgsAction.Options adbOptions = options.getOptions(WriteAdbArgsAction.Options.class);
+    if (adbOptions.start == StartType.WARM && !mobileInstallOptions.incremental) {
+      runtime.getReporter().handle(Event.warn(
+         "Warm start is enabled, but will have no effect on a non-incremental build"));
+    }
+
     List<String> targets = ProjectFileSupport.getTargets(runtime, options);
     BuildRequest request = BuildRequest.create(
         this.getClass().getAnnotation(Command.class).name(), options,