From d452e57da25d144a41634c8f91068e6028365ef8 Mon Sep 17 00:00:00 2001
From: Christopher Ferris <cferris@google.com>
Date: Fri, 19 Nov 2021 01:07:44 +0000
Subject: Add GetPrintableBuildID function to Elf object.

Bug: 197981919

Test: Unit tests pass.
Change-Id: I6373920ad09d005ffa93d08c573f865bae3c070e
---
 libunwindstack/Elf.cpp                   | 19 +++++++++++++++++++
 libunwindstack/MapInfo.cpp               | 12 +-----------
 libunwindstack/include/unwindstack/Elf.h |  4 ++++
 libunwindstack/tests/ElfTest.cpp         | 10 ++++++++++
 4 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/libunwindstack/Elf.cpp b/libunwindstack/Elf.cpp
index 7702f1f..53e9b24 100644
--- a/libunwindstack/Elf.cpp
+++ b/libunwindstack/Elf.cpp
@@ -22,6 +22,8 @@
 #include <string>
 #include <utility>
 
+#include <android-base/stringprintf.h>
+
 #include <unwindstack/Elf.h>
 #include <unwindstack/ElfInterface.h>
 #include <unwindstack/Log.h>
@@ -436,4 +438,21 @@ std::string Elf::GetBuildID(Memory* memory) {
   return "";
 }
 
+std::string Elf::GetPrintableBuildID(std::string& build_id) {
+  if (build_id.empty()) {
+    return "";
+  }
+  std::string printable_build_id;
+  for (const char& c : build_id) {
+    // Use %hhx to avoid sign extension on abis that have signed chars.
+    printable_build_id += android::base::StringPrintf("%02hhx", c);
+  }
+  return printable_build_id;
+}
+
+std::string Elf::GetPrintableBuildID() {
+  std::string build_id = GetBuildID();
+  return Elf::GetPrintableBuildID(build_id);
+}
+
 }  // namespace unwindstack
diff --git a/libunwindstack/MapInfo.cpp b/libunwindstack/MapInfo.cpp
index eb1987f..3d32066 100644
--- a/libunwindstack/MapInfo.cpp
+++ b/libunwindstack/MapInfo.cpp
@@ -23,8 +23,6 @@
 #include <mutex>
 #include <string>
 
-#include <android-base/stringprintf.h>
-
 #include <unwindstack/Elf.h>
 #include <unwindstack/MapInfo.h>
 #include <unwindstack/Maps.h>
@@ -415,15 +413,7 @@ MapInfo::ElfFields& MapInfo::GetElfFields() {
 
 std::string MapInfo::GetPrintableBuildID() {
   std::string raw_build_id = GetBuildID();
-  if (raw_build_id.empty()) {
-    return "";
-  }
-  std::string printable_build_id;
-  for (const char& c : raw_build_id) {
-    // Use %hhx to avoid sign extension on abis that have signed chars.
-    printable_build_id += android::base::StringPrintf("%02hhx", c);
-  }
-  return printable_build_id;
+  return Elf::GetPrintableBuildID(raw_build_id);
 }
 
 }  // namespace unwindstack
diff --git a/libunwindstack/include/unwindstack/Elf.h b/libunwindstack/include/unwindstack/Elf.h
index 01d9af9..328280d 100644
--- a/libunwindstack/include/unwindstack/Elf.h
+++ b/libunwindstack/include/unwindstack/Elf.h
@@ -68,6 +68,8 @@ class Elf {
 
   std::string GetBuildID();
 
+  std::string GetPrintableBuildID();
+
   int64_t GetLoadBias() { return load_bias_; }
 
   bool IsValidPc(uint64_t pc);
@@ -109,6 +111,8 @@ class Elf {
   static bool CacheGet(MapInfo* info);
   static bool CacheAfterCreateMemory(MapInfo* info);
 
+  static std::string GetPrintableBuildID(std::string& build_id);
+
  protected:
   bool valid_ = false;
   int64_t load_bias_ = 0;
diff --git a/libunwindstack/tests/ElfTest.cpp b/libunwindstack/tests/ElfTest.cpp
index 5af02ff..77a94be 100644
--- a/libunwindstack/tests/ElfTest.cpp
+++ b/libunwindstack/tests/ElfTest.cpp
@@ -551,4 +551,14 @@ TEST_F(ElfTest, error_code_valid) {
   EXPECT_EQ(0x1000U, elf.GetLastErrorAddress());
 }
 
+TEST_F(ElfTest, get_printable_build_id_empty) {
+  std::string empty;
+  ASSERT_EQ("", Elf::GetPrintableBuildID(empty));
+}
+
+TEST_F(ElfTest, get_printable_build_id_check) {
+  std::string empty = {'\xff', '\x45', '\x40', '\x0f'};
+  ASSERT_EQ("ff45400f", Elf::GetPrintableBuildID(empty));
+}
+
 }  // namespace unwindstack
-- 
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