Android RIL源码研究笔记 の ril (一)
Android源码目录hardware/ril/libril中总共包含5个C/CPP文件，它们分别是ril_commands.h、ril_unsol_commands.h、ril_event.h、ril_event.cpp和ril.cpp。这篇文章主要分析ril.cpp文件。我们可以将该文件划分为定义部分和实现部分，先来看定义部分：
[cpp]
#define LOG_TAG "RILC"
#include <hardware_legacy/power.h>
#include <telephony/ril.h>
#include <telephony/ril_cdma_sms.h>
#include <cutils/sockets.h>
#include <cutils/jstring.h>
#include <cutils/record_stream.h>
#include <utils/Log.h>
#include <utils/SystemClock.h>
#include <pthread.h>
#include <binder/Parcel.h>
#include <cutils/jstring.h>
#include <sys/types.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <assert.h>
#include <ctype.h>
#include <alloca.h>
#include <sys/un.h>
#include <assert.h>
#include <netinet/in.h>
#include <cutils/properties.h>
#include <ril_event.h>
namespace android {
#define PHONE_PROCESS "radio"
#define SOCKET_NAME_RIL "rild"
#define SOCKET_NAME_RIL_DEBUG "rild-debug"
#define ANDROID_WAKE_LOCK_NAME "radio-inte易做图ce"
#define PROPERTY_RIL_IMPL "gsm.version.ril-impl"
// match with constant in RIL.java
#define MAX_COMMAND_BYTES (8 * 1024)
// Basically: memset buffers that the client library
// shouldn't be using anymore in an attempt to find
// memory usage issues sooner.
#define MEMSET_FREED 1
// 常见的获取数组元素个数的方法
#define NUM_ELEMS(a) (sizeof (a) / sizeof (a)[0])
// 返回两数中较小者
#define MIN(a,b) ((a)<(b) ? (a) : (b))
/* WWW.zzzyk.com 回复类型：经过请求的回复和未经请求的回复*/
#define RESPONSE_SOLICITED 0
#define RESPONSE_UNSOLICITED 1
/* Negative values for private RIL errno's */
#define RIL_ERRNO_INVALID_RESPONSE -1
// request, response, and unsolicited msg print macro
// 即打印缓冲区printBuf的大小
#define PRINTBUF_SIZE 8096
// Enable RILC log
#define RILC_LOG 0
#if RILC_LOG
// 三个宏的调用顺序是startRequest - printRequest - closeRequest
// 这样打印出来的请求命令将包含在（）中
#define startRequest sprintf(printBuf, "(")
#define closeRequest sprintf(printBuf, "%s)", printBuf)
#define printRequest(token, req) \
LOGD("[%04d]> %s %s", token, requestToString(req), printBuf)
// 三个宏的调用顺序是startResponse - printResponse - closeResponse
// 这样打印出来的回复信息将包含在｛｝中
#define startResponse sprintf(printBuf, "%s {", printBuf)
#define closeResponse sprintf(printBuf, "%s}", printBuf)
#define printResponse LOGD("%s", printBuf)
#define clearPrintBuf printBuf[0] = 0
#define removeLastChar printBuf[strlen(printBuf)-1] = 0
#define appendPrintBuf(x...) sprintf(printBuf, x)
#else
#define startRequest
#define closeRequest
#define printRequest(token, req)
#define startResponse
#define closeResponse
#define printResponse
#define clearPrintBuf
#define removeLastChar
#define appendPrintBuf(x...)
#endif
// 唤醒类型：不唤醒，部分唤醒
enum WakeType {DONT_WAKE, WAKE_PARTIAL};
// "经过请求的回复"结构体定义：请求号，命令分发处理函数，返回结果响应函数
// 该结构体的取值见ril_commands.h文件
typedef struct {
int requestNumber;
void (*dispatchFunction) (Parcel &p, struct RequestInfo *pRI);
int(*responseFunction) (Parcel &p, void *response, size_t responselen);
} CommandInfo;
//"未经请求的回复"结构体定义：请求号，事件响应函数，唤醒类型
// 该结构体的取值见ril_unsol_commands.h文件
typedef struct {
int requestNumber;
int (*responseFunction) (Parcel &p, void *response, size_t responselen);
WakeType wakeType;
} UnsolResponseInfo;
// 请求信息结构体，封装CommandInfo，串成链表
typedef struct RequestInfo {
int32_t token; //this is not RIL_Token
CommandInfo *pCI;
struct RequestInfo *p_next;
char cancelled;
char local; // responses to local commands do not go back to command process
} RequestInfo;
// 用户回调信息结构体
typedef struct UserCallbackInfo {
RIL_TimedCallback p_callback; // 回调函数
void *userParam; // 回调函数的参数
struct ril_event event; // ril event
struct UserCallbackInfo *p_next; // 指向下一个回调信息结构（链表形式）
} UserCallbackInfo;
/*******************************************************************/
// 初始化回调结构
RIL_RadioFunctions s_callbacks = {0, NULL, NULL, NULL, NULL, NULL};
static int s_registerCalled = 0;
static pthread_t s_tid_dispatch; // 分发处理线程ID
static pthread_t s_tid_reader; // 读者线程ID
static int s_started = 0;
// 文件描述符初始化
static int s_fdListen = -1;
static int s_fdCommand = -1;
