From b473061c5a1b6e609188310e8d63f12380b4c74a Mon Sep 17 00:00:00 2001
From: Greg Kaiser <gkaiser@google.com>
Date: Mon, 24 Aug 2020 10:15:47 -0700
Subject: [PATCH] Fix API for C compatibility

In https://android-review.googlesource.com/c/platform/system/core/+/1224544
when we introduced a default argument to androidSetThreadPriority(),
we broke C compatibility with this API, and with the header file
in general.

We fix this up by instead introducing a new method that takes
three arguments.  This gets this header file compiling for C again,
and keeps this particular API C compatible.

Any C++ callers of the three argument version of
androidSetThreadPriority() will need to switch to using
androidSetThreadPriorityAndPolicy().  Although since this was
a recent change, we believe there is only one such user, which
we are fixing at the same time.

Test: TreeHugger
Bug: 165009705
Merged-In: Iab0b7e6c91a8e32a17ba1b186fd0c2fe96b601e4
Change-Id: Iab0b7e6c91a8e32a17ba1b186fd0c2fe96b601e4
---
 libutils/Threads.cpp                    | 12 +++++++++++-
 libutils/include/utils/AndroidThreads.h |  5 ++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/libutils/Threads.cpp b/libutils/Threads.cpp
index 147db542d..55eadb07a 100644
--- a/libutils/Threads.cpp
+++ b/libutils/Threads.cpp
@@ -302,7 +302,8 @@ void androidSetCreateThreadFunc(android_create_thread_fn func)
 }
 
 #if defined(__ANDROID__)
-int androidSetThreadPriority(pid_t tid, int pri, bool change_policy) {
+namespace {
+int androidSetThreadPriorityInternal(pid_t tid, int pri, bool change_policy) {
     int rc = 0;
     int lasterr = 0;
     int curr_pri = getpriority(PRIO_PROCESS, tid);
@@ -334,6 +335,15 @@ int androidSetThreadPriority(pid_t tid, int pri, bool change_policy) {
 
     return rc;
 }
+}  // namespace
+
+int androidSetThreadPriority(pid_t tid, int pri) {
+    return androidSetThreadPriorityInternal(tid, pri, true);
+}
+
+int androidSetThreadPriorityAndPolicy(pid_t tid, int pri, bool change_policy) {
+    return androidSetThreadPriorityInternal(tid, pri, change_policy);
+}
 
 int androidGetThreadPriority(pid_t tid) {
     return getpriority(PRIO_PROCESS, tid);
diff --git a/libutils/include/utils/AndroidThreads.h b/libutils/include/utils/AndroidThreads.h
index 3c30a2a85..cdb5442ae 100644
--- a/libutils/include/utils/AndroidThreads.h
+++ b/libutils/include/utils/AndroidThreads.h
@@ -78,9 +78,12 @@ extern void androidSetCreateThreadFunc(android_create_thread_fn func);
 // should be one of the ANDROID_PRIORITY constants.  Returns INVALID_OPERATION
 // if the priority set failed, else another value if just the group set failed;
 // in either case errno is set.  Thread ID zero means current thread.
+// This is equivalent to androidSetThreadPriorityAndPolicy(tid, prio, true);
+extern int androidSetThreadPriority(pid_t tid, int prio);
+
 // Parameter "change_policy" indicates if sched policy should be changed. It needs
 // not be checked again if the change is done elsewhere like activity manager.
-extern int androidSetThreadPriority(pid_t tid, int prio, bool change_policy = true);
+extern int androidSetThreadPriorityAndPolicy(pid_t tid, int prio, bool change_policy);
 
 // Get the current priority of a particular thread. Returns one of the
 // ANDROID_PRIORITY constants or a negative result in case of error.