Bug 894567: Use MemoryInfo.totalMem to get the device's total memory rather than parse /proc/meminfo. r=nalexander

Differential Revision: https://phabricator.services.mozilla.com/D33549

--HG--
extra : moz-landing-system : lando

mobile/android/base/java/org/mozilla/gecko/ANRReporter.java

@@ -300,7 +300,7 @@ public final class ANRReporter extends BroadcastReceiver
         return data.length;
     }
 
-    private static void fillPingHeader(OutputStream ping, String slug)
+    private static void fillPingHeader(Context context, OutputStream ping, String slug)
             throws IOException {
 
         // ping file header
@@ -332,7 +332,7 @@ public final class ANRReporter extends BroadcastReceiver
                 "\"platformBuildID\":" + JSONObject.quote(AppConstants.MOZ_APP_BUILDID) + "," +
                 "\"locale\":" + JSONObject.quote(Locales.getLanguageTag(Locale.getDefault())) + "," +
                 "\"cpucount\":" + String.valueOf(SysInfo.getCPUCount()) + "," +
-                "\"memsize\":" + String.valueOf(SysInfo.getMemSize()) + "," +
+                "\"memsize\":" + String.valueOf(SysInfo.getMemSize(context)) + "," +
                 "\"arch\":" + JSONObject.quote(SysInfo.getArchABI()) + "," +
                 "\"kernel_version\":" + JSONObject.quote(SysInfo.getKernelVersion()) + "," +
                 "\"device\":" + JSONObject.quote(SysInfo.getDevice()) + "," +
@@ -479,19 +479,19 @@ public final class ANRReporter extends BroadcastReceiver
         }
     }
 
-    private static void processTraces(Reader traces, File pingFile) {
+    private static void processTraces(Context context, Reader traces, File pingFile) {
 
         // Only get native stack if Gecko is running.
         // Also, unwinding is memory intensive, so only unwind if we have enough memory.
         final boolean haveNativeStack =
             GeckoThread.isRunning() ?
-            requestNativeStack(/* unwind */ SysInfo.getMemSize() >= 640) : false;
+            requestNativeStack(/* unwind */ SysInfo.getMemSize(context) >= 640) : false;
 
         try {
             OutputStream ping = new BufferedOutputStream(
                 new FileOutputStream(pingFile), TRACES_BLOCK_SIZE);
             try {
-                fillPingHeader(ping, pingFile.getName());
+                fillPingHeader(context, ping, pingFile.getName());
                 // Traces file has the format
                 //    ----- pid xxx at xxx -----
                 //    Cmd line: org.mozilla.xxx
@@ -527,12 +527,12 @@ public final class ANRReporter extends BroadcastReceiver
         }
     }
 
-    private static void processTraces(File tracesFile, File pingFile) {
+    private static void processTraces(Context context, File tracesFile, File pingFile) {
         try {
             Reader traces = new InputStreamReader(
                 new FileInputStream(tracesFile), TRACES_CHARSET);
             try {
-                processTraces(traces, pingFile);
+                processTraces(context, traces, pingFile);
             } finally {
                 traces.close();
             }
@@ -596,6 +596,6 @@ public final class ANRReporter extends BroadcastReceiver
             return;
         }
         Log.i(LOGTAG, "processing Gecko ANR");
-        processTraces(tracesFile, pingFile);
+        processTraces(context, tracesFile, pingFile);
     }
 }

mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoAppShell.java

@@ -1036,8 +1036,8 @@ public class GeckoAppShell {
         return sDensity;
     }
 
-    private static boolean isHighMemoryDevice() {
-        return HardwareUtils.getMemSize() > HIGH_MEMORY_DEVICE_THRESHOLD_MB;
+    private static boolean isHighMemoryDevice(final Context context) {
+        return SysInfo.getMemSize(context) > HIGH_MEMORY_DEVICE_THRESHOLD_MB;
     }
 
     public static synchronized void useMaxScreenDepth(final boolean enable) {
@@ -1052,11 +1052,11 @@ public class GeckoAppShell {
     public static synchronized int getScreenDepth() {
         if (sScreenDepth == 0) {
             sScreenDepth = 16;
+            final Context applicationContext = getApplicationContext();
             PixelFormat info = new PixelFormat();
-            final WindowManager wm = (WindowManager)
-                    getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
+            final WindowManager wm = (WindowManager) applicationContext.getSystemService(Context.WINDOW_SERVICE);
             PixelFormat.getPixelFormatInfo(wm.getDefaultDisplay().getPixelFormat(), info);
-            if (info.bitsPerPixel >= 24 && isHighMemoryDevice()) {
+            if (info.bitsPerPixel >= 24 && isHighMemoryDevice(applicationContext)) {
                 sScreenDepth = sUseMaxScreenDepth ? info.bitsPerPixel : 24;
             }
         }

mobile/android/geckoview/src/main/java/org/mozilla/gecko/SysInfo.java

@@ -5,15 +5,15 @@
 
 package org.mozilla.gecko;
 
+import android.app.ActivityManager;
+import android.app.ActivityManager.MemoryInfo;
+import android.content.Context;
 import android.util.Log;
 
 import org.mozilla.gecko.util.StrictModeContext;
 
 import java.io.File;
 import java.io.FileFilter;
-import java.io.FileInputStream;
-import java.io.FileNotFoundException;
-import java.io.IOException;
 
 import java.util.regex.Pattern;
 
@@ -77,96 +77,30 @@ public final class SysInfo {
     }
 
     /**
-     * Helper functions used to extract key/value data from /proc/meminfo
-     * Pulled from:
-     * http://androidxref.com/4.2_r1/xref/frameworks/base/core/java/com/android/internal/util/MemInfoReader.java
+     * Fetch the total memory of the device in MB.
+     *
+     * NB: This cannot be called before GeckoAppShell has been
+     * initialized.
+     *
+     * @return Memory size in MB.
      */
-    private static boolean matchMemText(final byte[] buffer, final int index,
-                                        final int bufferLength, final byte[] text) {
-        final int N = text.length;
-        if ((index + N) >= bufferLength) {
-            return false;
-        }
-        for (int i = 0; i < N; i++) {
-            if (buffer[index + i] != text[i]) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    /**
-     * Parses a line like:
-     *
-     *  MemTotal: 1605324 kB
-     *
-     * into 1605324.
-     *
-     * @return the first uninterrupted sequence of digits following the
-     *         specified index, parsed as an integer value in KB.
-     */
-    private static int extractMemValue(final byte[] buffer, final int offset, final int length) {
-        if (offset >= length) {
-            return 0;
-        }
-
-        int i = offset;
-        while (i < length && buffer[i] != '\n') {
-            if (buffer[i] >= '0' && buffer[i] <= '9') {
-                int start = i++;
-                while (i < length && buffer[i] >= '0' && buffer[i] <= '9') {
-                    ++i;
-                }
-                return Integer.parseInt(new String(buffer, start, i - start), 10);
-            }
-            ++i;
-        }
-        return 0;
-    }
-
-    /**
-     * Fetch the total memory of the device in MB by parsing /proc/meminfo.
-     *
-     * Of course, Android doesn't have a neat and tidy way to find total
-     * RAM, so we do it by parsing /proc/meminfo.
-     *
-     * @return 0 if a problem occurred, or memory size in MB.
-     */
-    @SuppressWarnings("try")
-    public static int getMemSize() {
+    public static int getMemSize(final Context context) {
         if (totalRAM >= 0) {
             return totalRAM;
         }
 
-        // This is the string "MemTotal" that we're searching for in the buffer.
-        final byte[] MEMTOTAL = {'M', 'e', 'm', 'T', 'o', 't', 'a', 'l'};
+        final MemoryInfo memInfo = new MemoryInfo();
 
-        // `/proc/meminfo` is not a real file and thus safe to read on the main thread.
-        try (StrictModeContext unused = StrictModeContext.allowDiskReads()) {
-            final byte[] buffer = new byte[MEMINFO_BUFFER_SIZE_BYTES];
-            final FileInputStream is = new FileInputStream("/proc/meminfo");
-            try {
-                final int length = is.read(buffer);
+        final ActivityManager am = (ActivityManager) context
+                                   .getSystemService(Context.ACTIVITY_SERVICE);
+        am.getMemoryInfo(memInfo);
+
+        // `getMemoryInfo()` returns a value in B. Convert to MB.
+        totalRAM = (int)(memInfo.totalMem / (1024 * 1024));
 
-                for (int i = 0; i < length; i++) {
-                    if (matchMemText(buffer, i, length, MEMTOTAL)) {
-                        i += 8;
-                        totalRAM = extractMemValue(buffer, i, length) / 1024;
         Log.d(LOG_TAG, "System memory: " + totalRAM + "MB.");
-                        return totalRAM;
-                    }
-                }
-            } finally {
-                is.close();
-            }
 
-            Log.w(LOG_TAG, "Did not find MemTotal line in /proc/meminfo.");
-            return totalRAM = 0;
-        } catch (FileNotFoundException f) {
-            return totalRAM = 0;
-        } catch (IOException e) {
-            return totalRAM = 0;
-        }
+        return totalRAM;
     }
 
     /**

mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareUtils.java

@@ -12,7 +12,6 @@ import android.os.Build;
 import android.system.Os;
 import android.util.Log;
 
-import org.mozilla.gecko.SysInfo;
 import org.mozilla.geckoview.BuildConfig;
 
 import java.io.File;
@@ -79,10 +78,6 @@ public final class HardwareUtils {
         return sIsTelevision;
     }
 
-    public static int getMemSize() {
-        return SysInfo.getMemSize();
-    }
-
     private static String getPreferredAbi() {
         String abi = null;
         if (Build.VERSION.SDK_INT >= 21) {