Add GTMTimeUtils (#229)

Utilities for relatively common desire to know the launch time of an app, or the boot time of a device.

3 files changed, 152 insertions, 0 deletions

diff --git a/Foundation/GTMTimeUtils.h b/Foundation/GTMTimeUtils.h
new file mode 100644
index 0000000..9b49532
--- /dev/null
+++ b/Foundation/GTMTimeUtils.h
@@ -0,0 +1,35 @@
+//
+//  GTMTimeUtils.h
+//
+//  Copyright 2018 Google LLC
+//
+//  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.
+//
+
+#import <Foundation/Foundation.h>
+
+// Return the date that the app was launched.
+NSDate *GTMAppLaunchDate(void);
+
+// Return the date that the device was started. Note on the simulator that this
+// returns the date that the computer was started, not the simulator.
+NSDate *GTMBootDate(void);
+
+// Convert a timeval to NSTimeInterval.
+NSTimeInterval GTMTimeValToNSTimeInterval(struct timeval time);
+
+// Timeval versions of the functions above if timevals are a more useful
+// structure to work with.
+struct timeval GTMBootTimeRelativeTo1970(void);
+struct timeval GTMAppLaunchTimeRelativeTo1970(void);
+
diff --git a/Foundation/GTMTimeUtils.m b/Foundation/GTMTimeUtils.m
new file mode 100644
index 0000000..2b551e4
--- /dev/null
+++ b/Foundation/GTMTimeUtils.m
@@ -0,0 +1,72 @@
+//
+//  GTMTimeUtils.m
+//
+//  Copyright 2018 Google LLC
+//
+//  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.
+//
+
+#import "GTMTimeUtils.h"
+
+#include <sys/sysctl.h>
+
+#import "GTMDefines.h"
+
+NSTimeInterval GTMTimeValToNSTimeInterval(struct timeval time) {
+  return time.tv_sec + (time.tv_usec / (double)USEC_PER_SEC);
+}
+
+struct timeval GTMBootTimeRelativeTo1970(void) {
+  struct timeval bootTime = { 0, 0 };
+  int mib[2] = { CTL_KERN, KERN_BOOTTIME };
+  size_t bootTimeSize = sizeof(bootTime);
+  if (sysctl(mib, 2, &bootTime, &bootTimeSize, NULL, 0) != 0) {
+    _GTMDevAssert(errno == 0, @"sysctl error - %d", errno);
+    struct timeval invalid = { 0, 0 };
+    return invalid;
+  }
+  return bootTime;
+}
+
+struct timeval GTMAppLaunchTimeRelativeTo1970(void) {
+  id_t pid = getpid();
+  int mib[] = { CTL_KERN, KERN_PROC, KERN_PROC_PID, (int)pid };
+  const size_t mibSize = sizeof(mib) / sizeof(mib[0]);
+  size_t infoSize = 0;
+
+  // Get initial size of KERN_PROC data structure.
+  if (sysctl(mib, mibSize, NULL, &infoSize, NULL, 0) != 0) {
+    _GTMDevAssert(errno == 0, @"sysctl error - %d", errno);
+    struct timeval invalid = { 0, 0 };
+    return invalid;
+  }
+  struct kinfo_proc info;
+  if (sysctl(mib, mibSize, &info, &infoSize, NULL, 0) != 0) {
+    _GTMDevAssert(errno == 0, @"sysctl error - %d", errno);
+    struct timeval invalid = { 0, 0 };
+    return invalid;
+  }
+  return info.kp_proc.p_starttime;
+}
+
+NSDate *GTMAppLaunchDate() {
+  NSTimeInterval ti =
+      GTMTimeValToNSTimeInterval(GTMAppLaunchTimeRelativeTo1970());
+  return [NSDate dateWithTimeIntervalSince1970:ti];
+}
+
+NSDate *GTMBootDate() {
+  NSTimeInterval ti =
+      GTMTimeValToNSTimeInterval(GTMBootTimeRelativeTo1970());
+  return [NSDate dateWithTimeIntervalSince1970:ti];
+}
diff --git a/Foundation/GTMTimeUtilsTest.m b/Foundation/GTMTimeUtilsTest.m
new file mode 100644
index 0000000..471cad0
--- /dev/null
+++ b/Foundation/GTMTimeUtilsTest.m
@@ -0,0 +1,45 @@
+//
+//  GTMTimeUtilsTest.m
+//
+//  Copyright 2018 Google LLC
+//
+//  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.
+//
+
+#import "GTMSenTestCase.h"
+#import "GTMTimeUtils.h"
+
+@interface GTMTimeUtilsTest : GTMTestCase
+@end
+
+@implementation GTMTimeUtilsTest
+
+- (void)testAppLaunchDate {
+  // Basic test to verify that "now" is after appLaunch.
+  NSDate *now = [NSDate date];
+  NSDate *appLaunch = GTMAppLaunchDate();
+
+  XCTAssertEqual([now compare:appLaunch], NSOrderedDescending,
+                 @"now: %@ appLaunch: %@", now, appLaunch);
+}
+
+- (void)testBootDate {
+  // Basic test to verify that appLaunch occurred after boot.
+  NSDate *appLaunch = GTMAppLaunchDate();
+  NSDate *boot = GTMBootDate();
+
+  XCTAssertEqual([appLaunch compare:boot], NSOrderedDescending,
+                 @"appLaunch: %@ boot: %@", appLaunch, boot);
+}
+
+@end