logd: liblog: logcat: Arbitrary time to tail

Change-Id: I10e8d92c933e31ee11e78d2d1114261a30c4be0e

1 files changed, 168 insertions, 0 deletions

diff --git a/liblog/log_time.cpp b/liblog/log_time.cpp
new file mode 100644
index 000000000..755c2d9bd
--- /dev/null
+++ b/liblog/log_time.cpp
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2014 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 <ctype.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/cdefs.h>
+
+#include <log/log_read.h>
+
+const char log_time::default_format[] = "%m-%d %H:%M:%S.%3q";
+const timespec log_time::EPOCH = { 0, 0 };
+
+// Add %#q for fractional seconds to standard strptime function
+
+char *log_time::strptime(const char *s, const char *format) {
+    time_t now;
+#ifdef __linux__
+    *this = log_time(CLOCK_REALTIME);
+    now = tv_sec;
+#else
+    time(&now);
+    tv_sec = now;
+    tv_nsec = 0;
+#endif
+
+    struct tm *ptm;
+#if (defined(HAVE_LOCALTIME_R))
+    struct tm tmBuf;
+    ptm = localtime_r(&now, &tmBuf);
+#else
+    ptm = localtime(&now);
+#endif
+
+    char fmt[strlen(format) + 1];
+    strcpy(fmt, format);
+
+    char *ret = const_cast<char *> (s);
+    char *cp;
+    for (char *f = cp = fmt; ; ++cp) {
+        if (!*cp) {
+            if (f != cp) {
+                ret = ::strptime(ret, f, ptm);
+            }
+            break;
+        }
+        if (*cp != '%') {
+            continue;
+        }
+        char *e = cp;
+        ++e;
+#if (defined(__BIONIC__))
+        if (*e == 's') {
+            *cp = '\0';
+            if (*f) {
+                ret = ::strptime(ret, f, ptm);
+                if (!ret) {
+                    break;
+                }
+            }
+            tv_sec = 0;
+            while (isdigit(*ret)) {
+                tv_sec = tv_sec * 10 + *ret - '0';
+                ++ret;
+            }
+            now = tv_sec;
+#if (defined(HAVE_LOCALTIME_R))
+            ptm = localtime_r(&now, &tmBuf);
+#else
+            ptm = localtime(&now);
+#endif
+        } else
+#endif
+        {
+            unsigned num = 0;
+            while (isdigit(*e)) {
+                num = num * 10 + *e - '0';
+                ++e;
+            }
+            if (*e != 'q') {
+                continue;
+            }
+            *cp = '\0';
+            if (*f) {
+                ret = ::strptime(ret, f, ptm);
+                if (!ret) {
+                    break;
+                }
+            }
+            unsigned long mul = NS_PER_SEC;
+            if (num == 0) {
+                num = INT_MAX;
+            }
+            tv_nsec = 0;
+            while (isdigit(*ret) && num && (mul > 1)) {
+                --num;
+                mul /= 10;
+                tv_nsec = tv_nsec + (*ret - '0') * mul;
+                ++ret;
+            }
+        }
+        f = cp = e;
+        ++f;
+    }
+
+    if (ret) {
+        tv_sec = mktime(ptm);
+        return ret;
+    }
+
+    // Upon error, place a known value into the class, the current time.
+#ifdef __linux__
+    *this = log_time(CLOCK_REALTIME);
+#else
+    time(&now);
+    tv_sec = now;
+    tv_nsec = 0;
+#endif
+    return ret;
+}
+
+log_time log_time::operator-= (const timespec &T) {
+    // No concept of negative time, clamp to EPOCH
+    if (*this <= T) {
+        return *this = EPOCH;
+    }
+
+    if (this->tv_nsec < (unsigned long int)T.tv_nsec) {
+        --this->tv_sec;
+        this->tv_nsec = NS_PER_SEC + this->tv_nsec - T.tv_nsec;
+    } else {
+        this->tv_nsec -= T.tv_nsec;
+    }
+    this->tv_sec -= T.tv_sec;
+
+    return *this;
+}
+
+log_time log_time::operator-= (const log_time &T) {
+    // No concept of negative time, clamp to EPOCH
+    if (*this <= T) {
+        return *this = EPOCH;
+    }
+
+    if (this->tv_nsec < T.tv_nsec) {
+        --this->tv_sec;
+        this->tv_nsec = NS_PER_SEC + this->tv_nsec - T.tv_nsec;
+    } else {
+        this->tv_nsec -= T.tv_nsec;
+    }
+    this->tv_sec -= T.tv_sec;
+
+    return *this;
+}