libsafestoi: Drop the usage of std::optional

- Drops the requirement of C++17
- Also adapt the library users code

aidl/battery/default/Android.bp

@@ -9,7 +9,6 @@ cc_binary {
     relative_install_path: "hw",
     init_rc: ["vendor.samsung_ext.framework.battery-service.rc"],
     vintf_fragments: ["vendor.samsung_ext.framework.battery-service.xml"],
-    defaults: ["safestoi_defaults"],
     srcs: [
         "SmartCharge.cpp",
         "service.cpp",
@@ -18,9 +17,9 @@ cc_binary {
         "libbase",
         "libbinder_ndk",
         "liblog",
+        "libsafestoi",
         "vendor.samsung_ext.framework.battery-V1-ndk",
     ],
     header_libs: ["libext_threadpool"],
-    cpp_std: "c++17",
     system_ext_specific: true,
 }

aidl/battery/default/SmartCharge.cpp

@@ -42,19 +42,18 @@ struct ConfigPair {
   std::string fromPair(void) {
     return std::to_string(first) + kComma + std::to_string(second);
   }
-  static std::optional<ConfigPair> fromString(const std::string &v) {
-    std::optional<int> first, second;
+  static bool fromString(const std::string &v, ConfigPair *pair) {
     std::stringstream ss(v);
     std::string res;
 
     if (v.find(kComma) != std::string::npos) {
       getline(ss, res, kComma);
-      first = stoi_safe(res);
+      pair->first = stoi_safe(res);
       getline(ss, res, kComma);
-      second = stoi_safe(res);
-      if (first && second) return ConfigPair{*first, *second};
+      pair->second = stoi_safe(res);
+      return true;
     }
-    return std::nullopt;
+    return false;
   }
 };
 
@@ -62,7 +61,7 @@ class BatteryHelper {
   static int _readSysfs(const char *sysfs) {
     std::string data;
     ReadFileToString(sysfs, &data);
-    return stoi_safe(data).value_or(-1);
+    return stoi_safe(data);
   }
 
  public:
@@ -72,14 +71,14 @@ class BatteryHelper {
   static int getPercent(void) { return _readSysfs(kBatteryPercentSysfs); }
 };
 
-static std::optional<ConfigPair> getAndParseIfPossible(const char *prop) {
+static bool getAndParse(const char *prop, ConfigPair *pair) {
   if (WaitForPropertyCreation(prop, std::chrono::milliseconds(500))) {
     std::string propval = GetProperty(prop, "");
     if (!propval.empty()) {
-      return ConfigPair::fromString(propval);
+      return ConfigPair::fromString(propval, pair);
     }
   }
-  return std::nullopt;
+  return false;
 }
 
 static inline bool verifyConfig(const int lower, const int upper) {
@@ -88,12 +87,12 @@ static inline bool verifyConfig(const int lower, const int upper) {
 
 SmartCharge::SmartCharge(void) {
   kPoolPtr = std::make_shared<ThreadPool>(3);
-#define func "<constructor>"
+#define func "SmartCharge()"
   kPoolPtr->Enqueue([this] {
-    auto ret = getAndParseIfPossible(kSmartChargeConfigProp);
-    if (ret.has_value() && verifyConfig(ret->first, ret->second)) {
-      upper = ret->second;
-      lower = ret->first;
+    ConfigPair ret {};
+    if (getAndParse(kSmartChargeConfigProp, &ret) && verifyConfig(ret.first, ret.second)) {
+      upper = ret.second;
+      lower = ret.first;
       ALOGD("%s: upper: %d, lower: %d", func, upper, lower);
     } else {
       upper = -1;
@@ -101,11 +100,10 @@ SmartCharge::SmartCharge(void) {
       ALOGW("%s: Parsing config failed", func);
       return;
     }
-    ret = getAndParseIfPossible(kSmartChargeEnabledProp);
-    if (ret.has_value() && !!ret->first) {
-      ALOGD("%s: Starting loop, withrestart: %d", func, !!ret->second);
+    if (getAndParse(kSmartChargeEnabledProp, &ret) && !!ret.first) {
+      ALOGD("%s: Starting loop, withrestart: %d", func, !!ret.second);
       kRun.store(true);
-      startLoop(!!ret->second);
+      startLoop(!!ret.second);
     } else
       ALOGD("%s: Not starting loop", func);
   });
@@ -127,7 +125,7 @@ void SmartCharge::startLoop(bool withrestart) {
     if (per < 0) {
       kRun.store(false);
       SetProperty(kSmartChargeEnabledProp, ConfigPair{0, 0}.fromPair());
-      ALOGE("%s: exit loop: per %d", __func__, per);
+      ALOGE("%s: exit loop: percent: %d", __func__, per);
       break;
     }
     if (per > upper)

aidl/battery/test_client/Android.bp

@@ -1,9 +1,9 @@
 cc_binary {
     name: "test_smartcharge",
-    defaults: ["safestoi_defaults"],
     shared_libs: [
         "libbase",
         "libbinder_ndk",
+        "libsafestoi",
         "vendor.samsung_ext.framework.battery-V1-ndk",
     ],
     header_libs: [

aidl/battery/test_client/main.cpp

@@ -17,18 +17,14 @@ int main(int argc, const char **argv) {
     fprintf(stderr, "getService returned null\n");
     return 1;
   }
-  std::optional<int> _arg1, _arg2, _arg3;
   int arg1, arg2, arg3;
-  _arg1 = stoi_safe(argv[1]);
-  _arg2 = stoi_safe(argv[2]);
-  _arg3 = stoi_safe(argv[3]);
-  if (!_arg1 || !_arg2 || !_arg3) {
-    fprintf(stderr, "Failed to parse arguments to int\n");
+  arg1 = stoi_safe(argv[1]);
+  arg2 = stoi_safe(argv[2]);
+  arg3 = stoi_safe(argv[3]);
+  if (arg1 < 0 || arg2 < 0 || arg3 < 0) {
+    fprintf(stderr, "Failed to parse arguments to int or is invalid input\n");
     return 1;
   }
-  arg1 = *_arg1;
-  arg2 = *_arg2;
-  arg3 = *_arg3;
   switch (arg1) {
   case 1: {
     TEST_LOG2(svc, setChargeLimit, arg2, arg3);

aidl/flashlight/default/Android.bp

@@ -3,7 +3,6 @@ cc_binary {
     relative_install_path: "hw",
     init_rc: ["vendor.samsung_ext.hardware.camera.flashlight-service.rc"],
     vintf_fragments: ["vendor.samsung_ext.hardware.camera.flashlight-service.xml"],
-    defaults: ["safestoi_defaults"],
     srcs: [
         "Flashlight.cpp",
         "service.cpp",
@@ -11,6 +10,7 @@ cc_binary {
     shared_libs: [
         "libbase",
         "libbinder_ndk",
+        "libsafestoi",
         "vendor.samsung_ext.hardware.camera.flashlight-V1-ndk",
     ],
     system_ext_specific: true,

aidl/flashlight/default/Flashlight.cpp

@@ -28,17 +28,16 @@ static constexpr const char *FLASH_BRIGHTNESS_PROP = "persist.ext.flashlight.las
 
 ndk::ScopedAStatus Flashlight::getCurrentBrightness(int32_t* _aidl_return) {
     std::string value;
-    int intvalue = -1;
+    int intvalue;
 
     ReadFileToString(FLASH_NODE, &value);
-    intvalue = stoi_safe(value).value_or(-1);
+    intvalue = stoi_safe(value);
     switch (intvalue) {
 	    case 0:
 		    *_aidl_return = 0;
 		    break;
 	    case 1:
-		    *_aidl_return = stoi_safe(GetProperty(FLASH_BRIGHTNESS_PROP, "1"))
-			    .value_or(level_saved);
+		    *_aidl_return = stoi_safe(GetProperty(FLASH_BRIGHTNESS_PROP, "1"), level_saved);
 		    break;
 	    case 1001:
 		    *_aidl_return = 1;

libsafestoi/Android.bp

@@ -1,13 +1,6 @@
 cc_library_shared {
-    name: "libstoisafe",
+    name: "libsafestoi",
     srcs: ["SafeStoi.cpp"],
     export_include_dirs: ["."],
-    cpp_std: "c++17",
     system_ext_specific: true,
 }
-
-cc_defaults {
-    name: "safestoi_defaults",
-    cpp_std: "c++17",
-    shared_libs: ["libstoisafe"],
-}

libsafestoi/SafeStoi.cpp

@@ -1,13 +1,12 @@
 #include "SafeStoi.h"
 
-#include <iostream>
 #include <sstream>
 
-std::optional<int> stoi_safe(const std::string& str) {
+int stoi_safe(const std::string& str, const int fallback) {
   std::istringstream iss(str);
   int value;
   if (!(iss >> value)) {
-    return std::nullopt;
+    return fallback;
   }
-  return std::optional(value);
+  return value;
 }

libsafestoi/SafeStoi.h

@@ -1,4 +1,3 @@
-#include <optional>
 #include <string>
 
-std::optional<int> stoi_safe(const std::string& str);
+int stoi_safe(const std::string& str, const int fallback = -1);