Move RSS HWM stats reading code under stats

The RSS high-water mark stats are used only by telemetry and should not
be a part of am package.

Modifications:
- avoid null, use empty string instead
- use assertThat from Truth

Bug: 140986627
Test: atest MemoryStatUtilTest
Test: atest ProcfsMemoryUtilTest
Test: statsd_testdrive for RSS HWM atom
Change-Id: I60140c085f1a47d71505955d79f545f52a4c4423

5 files changed, 169 insertions, 38 deletions

diff --git a/services/core/java/com/android/server/am/MemoryStatUtil.java b/services/core/java/com/android/server/am/MemoryStatUtil.java
index e73abd17cc07..fd64df9e86e0 100644
--- a/services/core/java/com/android/server/am/MemoryStatUtil.java
+++ b/services/core/java/com/android/server/am/MemoryStatUtil.java
@@ -63,8 +63,6 @@ public final class MemoryStatUtil {
     private static final Pattern CACHE_IN_BYTES = Pattern.compile("total_cache (\\d+)");
     private static final Pattern SWAP_IN_BYTES = Pattern.compile("total_swap (\\d+)");
 
-    private static final Pattern RSS_HIGH_WATERMARK_IN_KILOBYTES =
-            Pattern.compile("VmHWM:\\s*(\\d+)\\s*kB");
     private static final Pattern PROCFS_RSS_IN_KILOBYTES =
             Pattern.compile("VmRSS:\\s*(\\d+)\\s*kB");
     private static final Pattern PROCFS_ANON_RSS_IN_KILOBYTES =
@@ -113,15 +111,6 @@ public final class MemoryStatUtil {
     }
 
     /**
-     * Reads RSS high-water mark of a process from procfs. Returns value of the VmHWM field in
-     * /proc/PID/status in kilobytes or 0 if not available.
-     */
-    public static int readRssHighWaterMarkFromProcfs(int pid) {
-        final String statusPath = String.format(Locale.US, PROC_STATUS_FILE_FMT, pid);
-        return parseVmHWMFromProcfs(readFileContents(statusPath));
-    }
-
-    /**
      * Reads cmdline of a process from procfs.
      *
      * Returns content of /proc/pid/cmdline (e.g. /system/bin/statsd) or an empty string
@@ -204,19 +193,6 @@ public final class MemoryStatUtil {
     }
 
     /**
-     * Parses RSS high-water mark out from the contents of the /proc/pid/status file in procfs. The
-     * returned value is in kilobytes.
-     */
-    @VisibleForTesting
-    static int parseVmHWMFromProcfs(String procStatusContents) {
-        if (procStatusContents == null || procStatusContents.isEmpty()) {
-            return 0;
-        }
-        return (int) tryParseLong(RSS_HIGH_WATERMARK_IN_KILOBYTES, procStatusContents);
-    }
-
-
-    /**
      * Parses cmdline out of the contents of the /proc/pid/cmdline file in procfs.
      *
      * Parsing is required to strip anything after first null byte.
diff --git a/services/core/java/com/android/server/stats/ProcfsMemoryUtil.java b/services/core/java/com/android/server/stats/ProcfsMemoryUtil.java
new file mode 100644
index 000000000000..3076284a80ed
--- /dev/null
+++ b/services/core/java/com/android/server/stats/ProcfsMemoryUtil.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+package com.android.server.stats;
+
+import android.os.FileUtils;
+import android.util.Slog;
+
+import com.android.internal.annotations.VisibleForTesting;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Locale;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+final class ProcfsMemoryUtil {
+    private static final String TAG = "ProcfsMemoryUtil";
+
+    /** Path to procfs status file: /proc/pid/status. */
+    private static final String STATUS_FILE_FMT = "/proc/%d/status";
+
+    private static final Pattern RSS_HIGH_WATER_MARK_IN_KILOBYTES =
+            Pattern.compile("VmHWM:\\s*(\\d+)\\s*kB");
+
+    private ProcfsMemoryUtil() {}
+
+    /**
+     * Reads RSS high-water mark of a process from procfs. Returns value of the VmHWM field in
+     * /proc/PID/status in kilobytes or 0 if not available.
+     */
+    static int readRssHighWaterMarkFromProcfs(int pid) {
+        final String statusPath = String.format(Locale.US, STATUS_FILE_FMT, pid);
+        return parseVmHWMFromStatus(readFile(statusPath));
+    }
+
+    /**
+     * Parses RSS high-water mark out from the contents of the /proc/pid/status file in procfs. The
+     * returned value is in kilobytes.
+     */
+    @VisibleForTesting
+    static int parseVmHWMFromStatus(String contents) {
+        if (contents.isEmpty()) {
+            return 0;
+        }
+        final Matcher matcher = RSS_HIGH_WATER_MARK_IN_KILOBYTES.matcher(contents);
+        try {
+            return matcher.find() ? Integer.parseInt(matcher.group(1)) : 0;
+        } catch (NumberFormatException e) {
+            Slog.e(TAG, "Failed to parse value", e);
+            return 0;
+        }
+    }
+
+    private static String readFile(String path) {
+        try {
+            final File file = new File(path);
+            return FileUtils.readTextFile(file, 0 /* max */, null /* ellipsis */);
+        } catch (IOException e) {
+            return "";
+        }
+    }
+}
diff --git a/services/core/java/com/android/server/stats/StatsCompanionService.java b/services/core/java/com/android/server/stats/StatsCompanionService.java
index e92abfddac8f..19b80556a779 100644
--- a/services/core/java/com/android/server/stats/StatsCompanionService.java
+++ b/services/core/java/com/android/server/stats/StatsCompanionService.java
@@ -27,9 +27,9 @@ import static com.android.internal.util.Preconditions.checkNotNull;
 import static com.android.server.am.MemoryStatUtil.readCmdlineFromProcfs;
 import static com.android.server.am.MemoryStatUtil.readMemoryStatFromFilesystem;
 import static com.android.server.am.MemoryStatUtil.readMemoryStatFromProcfs;
-import static com.android.server.am.MemoryStatUtil.readRssHighWaterMarkFromProcfs;
 import static com.android.server.stats.IonMemoryUtil.readProcessSystemIonHeapSizesFromDebugfs;
 import static com.android.server.stats.IonMemoryUtil.readSystemIonHeapSizeFromDebugfs;
+import static com.android.server.stats.ProcfsMemoryUtil.readRssHighWaterMarkFromProcfs;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
diff --git a/services/tests/servicestests/src/com/android/server/am/MemoryStatUtilTest.java b/services/tests/servicestests/src/com/android/server/am/MemoryStatUtilTest.java
index 6a0d7f192adb..9e3b54d1ca96 100644
--- a/services/tests/servicestests/src/com/android/server/am/MemoryStatUtilTest.java
+++ b/services/tests/servicestests/src/com/android/server/am/MemoryStatUtilTest.java
@@ -22,7 +22,6 @@ import static com.android.server.am.MemoryStatUtil.MemoryStat;
 import static com.android.server.am.MemoryStatUtil.parseCmdlineFromProcfs;
 import static com.android.server.am.MemoryStatUtil.parseMemoryStatFromMemcg;
 import static com.android.server.am.MemoryStatUtil.parseMemoryStatFromProcfs;
-import static com.android.server.am.MemoryStatUtil.parseVmHWMFromProcfs;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
@@ -230,18 +229,6 @@ public class MemoryStatUtilTest {
     }
 
     @Test
-    public void testParseVmHWMFromProcfs_parsesCorrectValue() {
-        assertEquals(137668, parseVmHWMFromProcfs(PROC_STATUS_CONTENTS));
-    }
-
-    @Test
-    public void testParseVmHWMFromProcfs_emptyContents() {
-        assertEquals(0, parseVmHWMFromProcfs(""));
-
-        assertEquals(0, parseVmHWMFromProcfs(null));
-    }
-
-    @Test
     public void testParseCmdlineFromProcfs_invalidValue() {
         byte[] nothing = new byte[] {0x00, 0x74, 0x65, 0x73, 0x74}; // \0test
 
diff --git a/services/tests/servicestests/src/com/android/server/stats/ProcfsMemoryUtilTest.java b/services/tests/servicestests/src/com/android/server/stats/ProcfsMemoryUtilTest.java
new file mode 100644
index 000000000000..4fb533f726b2
--- /dev/null
+++ b/services/tests/servicestests/src/com/android/server/stats/ProcfsMemoryUtilTest.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+package com.android.server.stats;
+
+import static com.android.server.stats.ProcfsMemoryUtil.parseVmHWMFromStatus;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.test.filters.SmallTest;
+
+import org.junit.Test;
+
+/**
+ * Build/Install/Run:
+ *  atest FrameworksServicesTests:ProcfsMemoryUtilTest
+ */
+@SmallTest
+public class ProcfsMemoryUtilTest {
+    private static final String STATUS_CONTENTS = "Name:\tandroid.youtube\n"
+            + "State:\tS (sleeping)\n"
+            + "Tgid:\t12088\n"
+            + "Pid:\t12088\n"
+            + "PPid:\t723\n"
+            + "TracerPid:\t0\n"
+            + "Uid:\t10083\t10083\t10083\t10083\n"
+            + "Gid:\t10083\t10083\t10083\t10083\n"
+            + "Ngid:\t0\n"
+            + "FDSize:\t128\n"
+            + "Groups:\t3003 9997 20083 50083 \n"
+            + "VmPeak:\t 4546844 kB\n"
+            + "VmSize:\t 4542636 kB\n"
+            + "VmLck:\t       0 kB\n"
+            + "VmPin:\t       0 kB\n"
+            + "VmHWM:\t  137668 kB\n" // RSS high-water mark
+            + "VmRSS:\t  126776 kB\n" // RSS
+            + "RssAnon:\t   37860 kB\n"
+            + "RssFile:\t   88764 kB\n"
+            + "RssShmem:\t     152 kB\n"
+            + "VmData:\t 4125112 kB\n"
+            + "VmStk:\t    8192 kB\n"
+            + "VmExe:\t      24 kB\n"
+            + "VmLib:\t  102432 kB\n"
+            + "VmPTE:\t    1300 kB\n"
+            + "VmPMD:\t      36 kB\n"
+            + "VmSwap:\t      22 kB\n" // Swap
+            + "Threads:\t95\n"
+            + "SigQ:\t0/13641\n"
+            + "SigPnd:\t0000000000000000\n"
+            + "ShdPnd:\t0000000000000000\n"
+            + "SigBlk:\t0000000000001204\n"
+            + "SigIgn:\t0000000000000001\n"
+            + "SigCgt:\t00000006400084f8\n"
+            + "CapInh:\t0000000000000000\n"
+            + "CapPrm:\t0000000000000000\n"
+            + "CapEff:\t0000000000000000\n"
+            + "CapBnd:\t0000000000000000\n"
+            + "CapAmb:\t0000000000000000\n"
+            + "Seccomp:\t2\n"
+            + "Cpus_allowed:\tff\n"
+            + "Cpus_allowed_list:\t0-7\n"
+            + "Mems_allowed:\t1\n"
+            + "Mems_allowed_list:\t0\n"
+            + "voluntary_ctxt_switches:\t903\n"
+            + "nonvoluntary_ctxt_switches:\t104\n";
+
+    @Test
+    public void testParseVmHWMFromStatus_parsesCorrectValue() {
+        assertThat(parseVmHWMFromStatus(STATUS_CONTENTS)).isEqualTo(137668);
+    }
+
+    @Test
+    public void testParseVmHWMFromStatus_invalidValue() {
+        assertThat(parseVmHWMFromStatus("test\nVmHWM: x0x0x\ntest")).isEqualTo(0);
+    }
+
+    @Test
+    public void testParseVmHWMFromStatus_emptyContents() {
+        assertThat(parseVmHWMFromStatus("")).isEqualTo(0);
+    }
+}