liblog: correct new APIs per the API review

1) Rename __android_logger_data to __android_log_message and rename
   __android_log_write_logger_data to
   __android_log_write_log_message. Move the const char* message
   argument into __android_log_message.
2) Add @param, @return, and "Available since API level 30." to the
   documentation of new functions.
3) Document that the user defined aborter should but may not abort.
4) Document the line separation is the responsibility of the log
   function provided to __android_log_set_logger().

Bug: 150898477
Test: build, liblog and libbase unit tests
Change-Id: I07c41011ef25b3e7cc4943f3f1e240a2f6aa2802
diff --git a/liblog/include/android/log.h b/liblog/include/android/log.h
index 43a91ab..512c7cd 100644
--- a/liblog/include/android/log.h
+++ b/liblog/include/android/log.h
@@ -184,20 +184,21 @@
  * Logger data struct used for writing log messages to liblog via __android_log_write_logger_data()
  * and sending log messages to user defined loggers specified in __android_log_set_logger().
  */
-struct __android_logger_data {
-  size_t struct_size; /* Must be set to sizeof(__android_logger_data) and is used for versioning. */
-  int32_t buffer_id;  /* log_id_t or -1 to represent 'default'. */
-  int32_t priority;   /* android_LogPriority values. */
-  const char* tag;
-  const char* file;  /* Optional file name, may be set to nullptr. */
-  uint32_t line;     /* Optional line number, ignore if file is nullptr. */
+struct __android_log_message {
+  size_t
+      struct_size;   /** Must be set to sizeof(__android_log_message) and is used for versioning. */
+  int32_t buffer_id; /** {@link log_id_t} values. */
+  int32_t priority;  /** {@link android_LogPriority} values. */
+  const char* tag;   /** The tag for the log message. */
+  const char* file;  /** Optional file name, may be set to nullptr. */
+  uint32_t line;     /** Optional line number, ignore if file is nullptr. */
+  const char* message; /** The log message itself. */
 };
 
 /**
  * Prototype for the 'logger' function that is called for every log message.
  */
-typedef void (*__android_logger_function)(const struct __android_logger_data* logger_data,
-                                          const char* message);
+typedef void (*__android_logger_function)(const struct __android_log_message* log_message);
 /**
  * Prototype for the 'abort' function that is called when liblog will abort due to
  * __android_log_assert() failures.
@@ -206,52 +207,85 @@
 
 #if !defined(__ANDROID__) || __ANDROID_API__ >= 30
 /**
- * Writes the log message specified with logger_data and msg to the log.  logger_data includes
- * additional file name and line number information that a logger may use.  logger_data is versioned
- * for backwards compatibility.
+ * Writes the log message specified by log_message.  log_message includes additional file name and
+ * line number information that a logger may use.  log_message is versioned for backwards
+ * compatibility.
  * This assumes that loggability has already been checked through __android_log_is_loggable().
  * Higher level logging libraries, such as libbase, first check loggability, then format their
  * buffers, then pass the message to liblog via this function, and therefore we do not want to
  * duplicate the loggability check here.
+ *
+ * @param log_message the log message itself, see {@link __android_log_message}.
+ *
+ * Available since API level 30.
  */
-void __android_log_write_logger_data(struct __android_logger_data* logger_data, const char* msg)
-    __INTRODUCED_IN(30);
+void __android_log_write_log_message(struct __android_log_message* log_message) __INTRODUCED_IN(30);
 
 /**
  * Sets a user defined logger function.  All log messages sent to liblog will be set to the
- * function pointer specified by logger for processing.
+ * function pointer specified by logger for processing.  It is not expected that log messages are
+ * already terminated with a new line.  This function should add new lines if required for line
+ * separation.
+ *
+ * @param logger the new function that will handle log messages.
+ *
+ * Available since API level 30.
  */
 void __android_log_set_logger(__android_logger_function logger) __INTRODUCED_IN(30);
 
 /**
  * Writes the log message to logd.  This is an __android_logger_function and can be provided to
  * __android_log_set_logger().  It is the default logger when running liblog on a device.
+ *
+ * @param log_message the log message to write, see {@link __android_log_message}.
+ *
+ * Available since API level 30.
  */
-void __android_log_logd_logger(const struct __android_logger_data* logger_data, const char* msg)
-    __INTRODUCED_IN(30);
+void __android_log_logd_logger(const struct __android_log_message* log_message) __INTRODUCED_IN(30);
 
 /**
  * Writes the log message to stderr.  This is an __android_logger_function and can be provided to
  * __android_log_set_logger().  It is the default logger when running liblog on host.
+ *
+ * @param log_message the log message to write, see {@link __android_log_message}.
+ *
+ * Available since API level 30.
  */
-void __android_log_stderr_logger(const struct __android_logger_data* logger_data,
-                                 const char* message) __INTRODUCED_IN(30);
+void __android_log_stderr_logger(const struct __android_log_message* log_message)
+    __INTRODUCED_IN(30);
 
 /**
- * Sets a user defined aborter function that is called for __android_log_assert() failures.
+ * Sets a user defined aborter function that is called for __android_log_assert() failures.  This
+ * user defined aborter function is highly recommended to abort and be noreturn, but is not strictly
+ * required to.
+ *
+ * @param aborter the new aborter function, see {@link __android_aborter_function}.
+ *
+ * Available since API level 30.
  */
 void __android_log_set_aborter(__android_aborter_function aborter) __INTRODUCED_IN(30);
 
 /**
  * Calls the stored aborter function.  This allows for other logging libraries to use the same
  * aborter function by calling this function in liblog.
+ *
+ * @param abort_message an additional message supplied when aborting, for example this is used to
+ *                      call android_set_abort_message() in __android_log_default_aborter().
+ *
+ * Available since API level 30.
  */
 void __android_log_call_aborter(const char* abort_message) __INTRODUCED_IN(30);
 
 /**
  * Sets android_set_abort_message() on device then aborts().  This is the default aborter.
+ *
+ * @param abort_message an additional message supplied when aborting.  This functions calls
+ *                      android_set_abort_message() with its contents.
+ *
+ * Available since API level 30.
  */
-void __android_log_default_aborter(const char* abort_message) __INTRODUCED_IN(30);
+void __android_log_default_aborter(const char* abort_message) __attribute__((noreturn))
+__INTRODUCED_IN(30);
 
 /**
  * Use the per-tag properties "log.tag.<tagname>" along with the minimum priority from
@@ -263,7 +297,13 @@
  * minimum priority needed to log.  If only one is set, then that value is used to determine the
  * minimum priority needed.  If none are set, then default_priority is used.
  *
- * prio is ANDROID_LOG_VERBOSE to ANDROID_LOG_FATAL.
+ * @param prio         the priority to test, takes {@link android_LogPriority} values.
+ * @param tag          the tag to test.
+ * @param len          the length of the tag.
+ * @param default_prio the default priority to use if no properties or minimum priority are set.
+ * @return an integer where 1 indicates that the message is loggable and 0 indicates that it is not.
+ *
+ * Available since API level 30.
  */
 int __android_log_is_loggable(int prio, const char* tag, int default_prio) __INTRODUCED_IN(30);
 int __android_log_is_loggable_len(int prio, const char* tag, size_t len, int default_prio)
@@ -272,13 +312,22 @@
 /**
  * Sets the minimum priority that will be logged for this process.
  *
- * This returns the previous set minimum priority, or ANDROID_LOG_DEFAULT if none was set.
+ * @param priority the new minimum priority to set, takes @{link android_LogPriority} values.
+ * @return the previous set minimum priority as @{link android_LogPriority} values, or
+ *         ANDROID_LOG_DEFAULT if none was set.
+ *
+ * Available since API level 30.
  */
 int32_t __android_log_set_minimum_priority(int32_t priority) __INTRODUCED_IN(30);
 
 /**
  * Gets the minimum priority that will be logged for this process.  If none has been set by a
  * previous __android_log_set_minimum_priority() call, this returns ANDROID_LOG_DEFAULT.
+ *
+ * @return the current minimum priority as @{link android_LogPriority} values, or
+ *         ANDROID_LOG_DEFAULT if none is set.
+ *
+ * Available since API level 30.
  */
 int32_t __android_log_get_minimum_priority(void) __INTRODUCED_IN(30);
 
@@ -286,6 +335,10 @@
  * Sets the default tag if no tag is provided when writing a log message.  Defaults to
  * getprogname().  This truncates tag to the maximum log message size, though appropriate tags
  * should be much smaller.
+ *
+ * @param tag the new log tag.
+ *
+ * Available since API level 30.
  */
 void __android_log_set_default_tag(const char* tag) __INTRODUCED_IN(30);
 #endif
diff --git a/liblog/liblog.map.txt b/liblog/liblog.map.txt
index 198cdae..cff1509 100644
--- a/liblog/liblog.map.txt
+++ b/liblog/liblog.map.txt
@@ -77,7 +77,7 @@
     __android_log_set_logger;
     __android_log_set_minimum_priority;
     __android_log_stderr_logger;
-    __android_log_write_logger_data;
+    __android_log_write_log_message;
 };
 
 LIBLOG_PRIVATE {
diff --git a/liblog/logger_write.cpp b/liblog/logger_write.cpp
index a8620a0..c174b85 100644
--- a/liblog/logger_write.cpp
+++ b/liblog/logger_write.cpp
@@ -250,8 +250,7 @@
 #endif
 }
 
-void __android_log_stderr_logger(const struct __android_logger_data* logger_data,
-                                 const char* message) {
+void __android_log_stderr_logger(const struct __android_log_message* log_message) {
   struct tm now;
   time_t t = time(nullptr);
 
@@ -268,33 +267,32 @@
   static_assert(arraysize(log_characters) - 1 == ANDROID_LOG_SILENT,
                 "Mismatch in size of log_characters and values in android_LogPriority");
   int32_t priority =
-      logger_data->priority > ANDROID_LOG_SILENT ? ANDROID_LOG_FATAL : logger_data->priority;
+      log_message->priority > ANDROID_LOG_SILENT ? ANDROID_LOG_FATAL : log_message->priority;
   char priority_char = log_characters[priority];
   uint64_t tid = GetThreadId();
 
-  if (logger_data->file != nullptr) {
+  if (log_message->file != nullptr) {
     fprintf(stderr, "%s %c %s %5d %5" PRIu64 " %s:%u] %s\n",
-            logger_data->tag ? logger_data->tag : "nullptr", priority_char, timestamp, getpid(),
-            tid, logger_data->file, logger_data->line, message);
+            log_message->tag ? log_message->tag : "nullptr", priority_char, timestamp, getpid(),
+            tid, log_message->file, log_message->line, log_message->message);
   } else {
     fprintf(stderr, "%s %c %s %5d %5" PRIu64 " %s\n",
-            logger_data->tag ? logger_data->tag : "nullptr", priority_char, timestamp, getpid(),
-            tid, message);
+            log_message->tag ? log_message->tag : "nullptr", priority_char, timestamp, getpid(),
+            tid, log_message->message);
   }
 }
 
-void __android_log_logd_logger(const struct __android_logger_data* logger_data,
-                               const char* message) {
-  int buffer_id = logger_data->buffer_id == LOG_ID_DEFAULT ? LOG_ID_MAIN : logger_data->buffer_id;
+void __android_log_logd_logger(const struct __android_log_message* log_message) {
+  int buffer_id = log_message->buffer_id == LOG_ID_DEFAULT ? LOG_ID_MAIN : log_message->buffer_id;
 
   struct iovec vec[3];
   vec[0].iov_base =
-      const_cast<unsigned char*>(reinterpret_cast<const unsigned char*>(&logger_data->priority));
+      const_cast<unsigned char*>(reinterpret_cast<const unsigned char*>(&log_message->priority));
   vec[0].iov_len = 1;
-  vec[1].iov_base = const_cast<void*>(static_cast<const void*>(logger_data->tag));
-  vec[1].iov_len = strlen(logger_data->tag) + 1;
-  vec[2].iov_base = const_cast<void*>(static_cast<const void*>(message));
-  vec[2].iov_len = strlen(message) + 1;
+  vec[1].iov_base = const_cast<void*>(static_cast<const void*>(log_message->tag));
+  vec[1].iov_len = strlen(log_message->tag) + 1;
+  vec[2].iov_base = const_cast<void*>(static_cast<const void*>(log_message->message));
+  vec[2].iov_len = strlen(log_message->message) + 1;
 
   write_to_log(static_cast<log_id_t>(buffer_id), vec, 3);
 }
@@ -303,29 +301,29 @@
   return __android_log_buf_write(LOG_ID_MAIN, prio, tag, msg);
 }
 
-void __android_log_write_logger_data(__android_logger_data* logger_data, const char* msg) {
+void __android_log_write_log_message(__android_log_message* log_message) {
   ErrnoRestorer errno_restorer;
 
-  if (logger_data->buffer_id != LOG_ID_DEFAULT && logger_data->buffer_id != LOG_ID_MAIN &&
-      logger_data->buffer_id != LOG_ID_SYSTEM && logger_data->buffer_id != LOG_ID_RADIO &&
-      logger_data->buffer_id != LOG_ID_CRASH) {
+  if (log_message->buffer_id != LOG_ID_DEFAULT && log_message->buffer_id != LOG_ID_MAIN &&
+      log_message->buffer_id != LOG_ID_SYSTEM && log_message->buffer_id != LOG_ID_RADIO &&
+      log_message->buffer_id != LOG_ID_CRASH) {
     return;
   }
 
   auto tag_lock = std::shared_lock{default_tag_lock, std::defer_lock};
-  if (logger_data->tag == nullptr) {
+  if (log_message->tag == nullptr) {
     tag_lock.lock();
-    logger_data->tag = GetDefaultTag().c_str();
+    log_message->tag = GetDefaultTag().c_str();
   }
 
 #if __BIONIC__
-  if (logger_data->priority == ANDROID_LOG_FATAL) {
-    android_set_abort_message(msg);
+  if (log_message->priority == ANDROID_LOG_FATAL) {
+    android_set_abort_message(log_message->message);
   }
 #endif
 
   auto lock = std::shared_lock{logger_function_lock};
-  logger_function(logger_data, msg);
+  logger_function(log_message);
 }
 
 int __android_log_buf_write(int bufID, int prio, const char* tag, const char* msg) {
@@ -335,8 +333,9 @@
     return 0;
   }
 
-  __android_logger_data logger_data = {sizeof(__android_logger_data), bufID, prio, tag, nullptr, 0};
-  __android_log_write_logger_data(&logger_data, msg);
+  __android_log_message log_message = {
+      sizeof(__android_log_message), bufID, prio, tag, nullptr, 0, msg};
+  __android_log_write_log_message(&log_message);
   return 1;
 }
 
@@ -351,9 +350,9 @@
 
   vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
 
-  __android_logger_data logger_data = {
-      sizeof(__android_logger_data), LOG_ID_MAIN, prio, tag, nullptr, 0};
-  __android_log_write_logger_data(&logger_data, buf);
+  __android_log_message log_message = {
+      sizeof(__android_log_message), LOG_ID_MAIN, prio, tag, nullptr, 0, buf};
+  __android_log_write_log_message(&log_message);
   return 1;
 }
 
@@ -371,9 +370,9 @@
   vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
   va_end(ap);
 
-  __android_logger_data logger_data = {
-      sizeof(__android_logger_data), LOG_ID_MAIN, prio, tag, nullptr, 0};
-  __android_log_write_logger_data(&logger_data, buf);
+  __android_log_message log_message = {
+      sizeof(__android_log_message), LOG_ID_MAIN, prio, tag, nullptr, 0, buf};
+  __android_log_write_log_message(&log_message);
   return 1;
 }
 
@@ -391,8 +390,9 @@
   vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
   va_end(ap);
 
-  __android_logger_data logger_data = {sizeof(__android_logger_data), bufID, prio, tag, nullptr, 0};
-  __android_log_write_logger_data(&logger_data, buf);
+  __android_log_message log_message = {
+      sizeof(__android_log_message), bufID, prio, tag, nullptr, 0, buf};
+  __android_log_write_log_message(&log_message);
   return 1;
 }
 
diff --git a/liblog/tests/liblog_global_state.cpp b/liblog/tests/liblog_global_state.cpp
index 9a181ef..3508818 100644
--- a/liblog/tests/liblog_global_state.cpp
+++ b/liblog/tests/liblog_global_state.cpp
@@ -59,16 +59,15 @@
   static unsigned int expected_line;
   static std::string expected_message = "libbase test message";
 
-  auto liblog_logger_function = [](const struct __android_logger_data* logger_data,
-                                   const char* message) {
+  auto liblog_logger_function = [](const struct __android_log_message* log_message) {
     message_seen = true;
-    EXPECT_EQ(sizeof(__android_logger_data), logger_data->struct_size);
-    EXPECT_EQ(LOG_ID_DEFAULT, logger_data->buffer_id);
-    EXPECT_EQ(ANDROID_LOG_WARN, logger_data->priority);
-    EXPECT_STREQ(LOG_TAG, logger_data->tag);
-    EXPECT_EQ(expected_file, logger_data->file);
-    EXPECT_EQ(expected_line, logger_data->line);
-    EXPECT_EQ(expected_message, message);
+    EXPECT_EQ(sizeof(__android_log_message), log_message->struct_size);
+    EXPECT_EQ(LOG_ID_DEFAULT, log_message->buffer_id);
+    EXPECT_EQ(ANDROID_LOG_WARN, log_message->priority);
+    EXPECT_STREQ(LOG_TAG, log_message->tag);
+    EXPECT_EQ(expected_file, log_message->file);
+    EXPECT_EQ(expected_line, log_message->line);
+    EXPECT_EQ(expected_message, log_message->message);
   };
 
   __android_log_set_logger(liblog_logger_function);
@@ -111,16 +110,15 @@
   static int expected_priority = ANDROID_LOG_WARN;
   static std::string expected_message = "libbase test message";
 
-  auto liblog_logger_function = [](const struct __android_logger_data* logger_data,
-                                   const char* message) {
+  auto liblog_logger_function = [](const struct __android_log_message* log_message) {
     message_seen = true;
-    EXPECT_EQ(sizeof(__android_logger_data), logger_data->struct_size);
-    EXPECT_EQ(expected_buffer_id, logger_data->buffer_id);
-    EXPECT_EQ(expected_priority, logger_data->priority);
-    EXPECT_STREQ(LOG_TAG, logger_data->tag);
-    EXPECT_STREQ(nullptr, logger_data->file);
-    EXPECT_EQ(0U, logger_data->line);
-    EXPECT_EQ(expected_message, message);
+    EXPECT_EQ(sizeof(__android_log_message), log_message->struct_size);
+    EXPECT_EQ(expected_buffer_id, log_message->buffer_id);
+    EXPECT_EQ(expected_priority, log_message->priority);
+    EXPECT_STREQ(LOG_TAG, log_message->tag);
+    EXPECT_STREQ(nullptr, log_message->file);
+    EXPECT_EQ(0U, log_message->line);
+    EXPECT_EQ(expected_message, log_message->message);
   };
 
   __android_log_set_logger(liblog_logger_function);