Add std::string system property functions.
Makes it easier to write correct code in a world where the maximum
property key/value lengths change.
Bug: http://b/23102347
Test: libbase_test64
Change-Id: I100f00904221bbcef9e8786a4e6e30428039bb49
diff --git a/base/Android.bp b/base/Android.bp
index e260412..88d8ad1 100644
--- a/base/Android.bp
+++ b/base/Android.bp
@@ -39,7 +39,10 @@
shared_libs: ["liblog"],
target: {
android: {
- srcs: ["errors_unix.cpp"],
+ srcs: [
+ "errors_unix.cpp",
+ "properties.cpp",
+ ],
cppflags: ["-Wexit-time-destructors"],
},
darwin: {
@@ -78,6 +81,9 @@
"test_main.cpp",
],
target: {
+ android: {
+ srcs: ["properties_test.cpp"],
+ },
windows: {
srcs: ["utf8_test.cpp"],
enabled: true,
diff --git a/base/include/android-base/properties.h b/base/include/android-base/properties.h
new file mode 100644
index 0000000..95d1b6a
--- /dev/null
+++ b/base/include/android-base/properties.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_BASE_PROPERTIES_H
+#define ANDROID_BASE_PROPERTIES_H
+
+#include <sys/cdefs.h>
+
+#if !defined(__BIONIC__)
+#error Only bionic supports system properties.
+#endif
+
+#include <limits>
+#include <string>
+
+namespace android {
+namespace base {
+
+// Returns the current value of the system property `key`,
+// or `default_value` if the property is empty or doesn't exist.
+std::string GetProperty(const std::string& key, const std::string& default_value);
+
+// Returns true if the system property `key` has the value "1", "y", "yes", "on", or "true",
+// false for "0", "n", "no", "off", or "false", or `default_value` otherwise.
+bool GetBoolProperty(const std::string& key, bool default_value);
+
+// Returns the signed integer corresponding to the system property `key`.
+// If the property is empty, doesn't exist, doesn't have an integer value, or is outside
+// the optional bounds, returns `default_value`.
+template <typename T> T GetIntProperty(const std::string& key,
+ T default_value,
+ T min = std::numeric_limits<T>::min(),
+ T max = std::numeric_limits<T>::max());
+
+// Returns the unsigned integer corresponding to the system property `key`.
+// If the property is empty, doesn't exist, doesn't have an integer value, or is outside
+// the optional bound, returns `default_value`.
+template <typename T> T GetUintProperty(const std::string& key,
+ T default_value,
+ T max = std::numeric_limits<T>::max());
+
+// Sets the system property `key` to `value`.
+// Note that system property setting is inherently asynchronous so a return value of `true`
+// isn't particularly meaningful, and immediately reading back the value won't necessarily
+// tell you whether or not your call succeeded. A `false` return value definitely means failure.
+bool SetProperty(const std::string& key, const std::string& value);
+
+} // namespace base
+} // namespace android
+
+#endif // ANDROID_BASE_MEMORY_H
diff --git a/base/properties.cpp b/base/properties.cpp
new file mode 100644
index 0000000..fab3005
--- /dev/null
+++ b/base/properties.cpp
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "android-base/properties.h"
+
+#include <sys/system_properties.h>
+
+#include <string>
+
+#include <android-base/parseint.h>
+
+namespace android {
+namespace base {
+
+std::string GetProperty(const std::string& key, const std::string& default_value) {
+ const prop_info* pi = __system_property_find(key.c_str());
+ if (pi == nullptr) return default_value;
+
+ char buf[PROP_VALUE_MAX];
+ if (__system_property_read(pi, nullptr, buf) > 0) return buf;
+
+ // If the property exists but is empty, also return the default value.
+ // Since we can't remove system properties, "empty" is traditionally
+ // the same as "missing" (this was true for cutils' property_get).
+ return default_value;
+}
+
+bool GetBoolProperty(const std::string& key, bool default_value) {
+ std::string value = GetProperty(key, "");
+ if (value == "1" || value == "y" || value == "yes" || value == "on" || value == "true") {
+ return true;
+ } else if (value == "0" || value == "n" || value == "no" || value == "off" || value == "false") {
+ return false;
+ }
+ return default_value;
+}
+
+template <typename T>
+T GetIntProperty(const std::string& key, T default_value, T min, T max) {
+ T result;
+ std::string value = GetProperty(key, "");
+ if (!value.empty() && android::base::ParseInt(value.c_str(), &result, min, max)) return result;
+ return default_value;
+}
+
+template <typename T>
+T GetUintProperty(const std::string& key, T default_value, T max) {
+ T result;
+ std::string value = GetProperty(key, "");
+ if (!value.empty() && android::base::ParseUint(value.c_str(), &result, max)) return result;
+ return default_value;
+}
+
+template int8_t GetIntProperty(const std::string&, int8_t, int8_t, int8_t);
+template int16_t GetIntProperty(const std::string&, int16_t, int16_t, int16_t);
+template int32_t GetIntProperty(const std::string&, int32_t, int32_t, int32_t);
+template int64_t GetIntProperty(const std::string&, int64_t, int64_t, int64_t);
+
+template uint8_t GetUintProperty(const std::string&, uint8_t, uint8_t);
+template uint16_t GetUintProperty(const std::string&, uint16_t, uint16_t);
+template uint32_t GetUintProperty(const std::string&, uint32_t, uint32_t);
+template uint64_t GetUintProperty(const std::string&, uint64_t, uint64_t);
+
+bool SetProperty(const std::string& key, const std::string& value) {
+ return (__system_property_set(key.c_str(), value.c_str()) == 0);
+}
+
+} // namespace base
+} // namespace android
diff --git a/base/properties_test.cpp b/base/properties_test.cpp
new file mode 100644
index 0000000..da89ec5
--- /dev/null
+++ b/base/properties_test.cpp
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "android-base/properties.h"
+
+#include <gtest/gtest.h>
+
+#include <string>
+
+TEST(properties, smoke) {
+ android::base::SetProperty("debug.libbase.property_test", "hello");
+
+ std::string s = android::base::GetProperty("debug.libbase.property_test", "");
+ ASSERT_EQ("hello", s);
+
+ android::base::SetProperty("debug.libbase.property_test", "world");
+ s = android::base::GetProperty("debug.libbase.property_test", "");
+ ASSERT_EQ("world", s);
+
+ s = android::base::GetProperty("this.property.does.not.exist", "");
+ ASSERT_EQ("", s);
+
+ s = android::base::GetProperty("this.property.does.not.exist", "default");
+ ASSERT_EQ("default", s);
+}
+
+TEST(properties, empty) {
+ // Because you can't delete a property, people "delete" them by
+ // setting them to the empty string. In that case we'd want to
+ // keep the default value (like cutils' property_get did).
+ android::base::SetProperty("debug.libbase.property_test", "");
+ std::string s = android::base::GetProperty("debug.libbase.property_test", "default");
+ ASSERT_EQ("default", s);
+}
+
+static void CheckGetBoolProperty(bool expected, const std::string& value, bool default_value) {
+ android::base::SetProperty("debug.libbase.property_test", value.c_str());
+ ASSERT_EQ(expected, android::base::GetBoolProperty("debug.libbase.property_test", default_value));
+}
+
+TEST(properties, GetBoolProperty_true) {
+ CheckGetBoolProperty(true, "1", false);
+ CheckGetBoolProperty(true, "y", false);
+ CheckGetBoolProperty(true, "yes", false);
+ CheckGetBoolProperty(true, "on", false);
+ CheckGetBoolProperty(true, "true", false);
+}
+
+TEST(properties, GetBoolProperty_false) {
+ CheckGetBoolProperty(false, "0", true);
+ CheckGetBoolProperty(false, "n", true);
+ CheckGetBoolProperty(false, "no", true);
+ CheckGetBoolProperty(false, "off", true);
+ CheckGetBoolProperty(false, "false", true);
+}
+
+TEST(properties, GetBoolProperty_default) {
+ CheckGetBoolProperty(true, "burp", true);
+ CheckGetBoolProperty(false, "burp", false);
+}
+
+template <typename T> void CheckGetIntProperty() {
+ // Positive and negative.
+ android::base::SetProperty("debug.libbase.property_test", "-12");
+ EXPECT_EQ(T(-12), android::base::GetIntProperty<T>("debug.libbase.property_test", 45));
+ android::base::SetProperty("debug.libbase.property_test", "12");
+ EXPECT_EQ(T(12), android::base::GetIntProperty<T>("debug.libbase.property_test", 45));
+
+ // Default value.
+ android::base::SetProperty("debug.libbase.property_test", "");
+ EXPECT_EQ(T(45), android::base::GetIntProperty<T>("debug.libbase.property_test", 45));
+
+ // Bounds checks.
+ android::base::SetProperty("debug.libbase.property_test", "0");
+ EXPECT_EQ(T(45), android::base::GetIntProperty<T>("debug.libbase.property_test", 45, 1, 2));
+ android::base::SetProperty("debug.libbase.property_test", "1");
+ EXPECT_EQ(T(1), android::base::GetIntProperty<T>("debug.libbase.property_test", 45, 1, 2));
+ android::base::SetProperty("debug.libbase.property_test", "2");
+ EXPECT_EQ(T(2), android::base::GetIntProperty<T>("debug.libbase.property_test", 45, 1, 2));
+ android::base::SetProperty("debug.libbase.property_test", "3");
+ EXPECT_EQ(T(45), android::base::GetIntProperty<T>("debug.libbase.property_test", 45, 1, 2));
+}
+
+template <typename T> void CheckGetUintProperty() {
+ // Positive.
+ android::base::SetProperty("debug.libbase.property_test", "12");
+ EXPECT_EQ(T(12), android::base::GetUintProperty<T>("debug.libbase.property_test", 45));
+
+ // Default value.
+ android::base::SetProperty("debug.libbase.property_test", "");
+ EXPECT_EQ(T(45), android::base::GetUintProperty<T>("debug.libbase.property_test", 45));
+
+ // Bounds checks.
+ android::base::SetProperty("debug.libbase.property_test", "12");
+ EXPECT_EQ(T(12), android::base::GetUintProperty<T>("debug.libbase.property_test", 33, 22));
+ android::base::SetProperty("debug.libbase.property_test", "12");
+ EXPECT_EQ(T(5), android::base::GetUintProperty<T>("debug.libbase.property_test", 5, 10));
+}
+
+TEST(properties, GetIntProperty_int8_t) { CheckGetIntProperty<int8_t>(); }
+TEST(properties, GetIntProperty_int16_t) { CheckGetIntProperty<int16_t>(); }
+TEST(properties, GetIntProperty_int32_t) { CheckGetIntProperty<int32_t>(); }
+TEST(properties, GetIntProperty_int64_t) { CheckGetIntProperty<int64_t>(); }
+
+TEST(properties, GetUintProperty_uint8_t) { CheckGetUintProperty<uint8_t>(); }
+TEST(properties, GetUintProperty_uint16_t) { CheckGetUintProperty<uint16_t>(); }
+TEST(properties, GetUintProperty_uint32_t) { CheckGetUintProperty<uint32_t>(); }
+TEST(properties, GetUintProperty_uint64_t) { CheckGetUintProperty<uint64_t>(); }
