新增《PHP扩展开发》-协程-修复一些bug（一）

README.md

@@ -38,3 +38,4 @@ PHP版本：7.3.5
 
 [16、协程getCid](./docs/《PHP扩展开发》-协程-协程getCid.md)
 
+[17、修复一些bug（一）](./docs/《PHP扩展开发》-协程-修复一些bug（一）.md)
\ No newline at end of file

docs/《PHP扩展开发》-协程-修复一些bug（一）.md

+# 修复一些bug（一）
+
+开发到这里，我们需要停下来修复一些bug。我们通过具体的脚本例子来触发这个bug，然后我们通过调试分析，来修复这个bug。或许有些读者在阅读的时候发现了明显的bug，实际上，这些bug是故意留出来的，因为我们这一系列的教程是渐进式的，不会一气呵成。否则就失去了意义，那样只会和源码分析没啥区别。
+
+OK，我们来看这个脚本：
+
+```php
+<?php
+
+function task($arg)
+{
+	$cid = Study\Coroutine::getCid();
+	echo "coroutine [{$cid}] create" . PHP_EOL;
+	Study\Coroutine::yield();
+	echo "coroutine [{$cid}] create" . PHP_EOL;
+}
+
+echo "main coroutine" . PHP_EOL;
+$cid1 = Study\Coroutine::create('task', 'a');
+echo "main coroutine" . PHP_EOL;
+$cid2 = Study\Coroutine::create('task', 'b');
+echo "main coroutine" . PHP_EOL;
+
+Study\Coroutine::resume($cid1);
+echo "main coroutine" . PHP_EOL;
+Study\Coroutine::resume($cid2);
+echo "main coroutine" . PHP_EOL;
+Study\Coroutine::resume($cid2);
+```
+
+和之前脚本的区别在于最后几行，我调用了2次`resume($cid2)`。
+
+OK，我们来执行一下脚本：
+
+```shell
+~/codeDir/cppCode/study # php test.php 
+main coroutine
+coroutine [1] create
+main coroutine
+coroutine [2] create
+main coroutine
+coroutine [1] create
+main coroutine
+coroutine [2] create
+main coroutine
+Segmentation fault
+~/codeDir/cppCode/study # 
+```
+
+我们发现，报了一错`Segmentation fault`。
+
+我们来调试一下：
+
+```shell
+~/codeDir/cppCode/study # cgdb php
+GNU gdb (GDB) 8.2
+Copyright (C) 2018 Free Software Foundation, Inc.
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
+Type "show copying" and "show warranty" for details.
+This GDB was configured as "x86_64-alpine-linux-musl".
+Type "show configuration" for configuration details.
+For bug reporting instructions, please see:
+<http://www.gnu.org/software/gdb/bugs/>.
+Find the GDB manual and other documentation resources online at:
+    <http://www.gnu.org/software/gdb/documentation/>.
+
+For help, type "help".
+Type "apropos word" to search for commands related to "word"...
+Reading symbols from php...(no debugging symbols found)...done.
+(gdb) 
+```
+
+然后执行脚本：
+
+```shell
+(gdb) r test.php
+This GDB was configured as "x86_64-alpine-linux-musl".
+Type "show configuration" for configuration details.
+For bug reporting instructions, please see:
+<http://www.gnu.org/software/gdb/bugs/>.
+Find the GDB manual and other documentation resources online at:
+    <http://www.gnu.org/software/gdb/documentation/>.
+
+For help, type "help".
+Type "apropos word" to search for commands related to "word"...
+Reading symbols from php...(no debugging symbols found)...done.
+(gdb) r test.php 
+Starting program: /usr/local/bin/php test.php
+main coroutine
+coroutine [1] create
+main coroutine
+coroutine [2] create
+main coroutine
+coroutine [1] create
+main coroutine
+coroutine [2] create
+main coroutine
+
+Program received signal SIGSEGV, Segmentation fault.
+zim_study_coroutine_util_resume (execute_data=0x7ffff761d110, return_value=0x7fffffffb0b0) at /root/codeDir/cppCode/study/study_coroutine_util.cc:54
+(gdb) 
+```
+
+我们发现报错地方是`study_coroutine_util.cc:54`。对应的代码是：
+
+```cpp
+Coroutine* co = coroutine_iterator->second;
+```
+
+很容易想到问题肯定是出在了`coroutine_iterator->second`上面。
+
+OK，我们在函数`zim_study_coroutine_util_resume`打一个断点：
+
+```cpp
+(gdb) b zim_study_coroutine_util_resume
+Breakpoint 1 at 0x7ffff78d1b8a: file /root/codeDir/cppCode/study/study_coroutine_util.cc, line 45.
+(gdb) 
+```
+
+然后我们重新执行脚本：
+
+```shell
+(gdb) r test.php 
+The program being debugged has been started already.
+Start it from the beginning? (y or n) y
+The program being debugged has been started already.
+Starting program: /usr/local/bin/php test.php
+main coroutine
+coroutine [1] create
+main coroutine
+coroutine [2] create
+main coroutine
+
+Breakpoint 1, zim_study_coroutine_util_resume (execute_data=0x7ffff761d110, return_value=0x7fffffffb0b0) at /root/codeDir/cppCode/study/study_coroutine_util.cc:45
+(gdb) 
+```
+
+我们继续执行：
+
+```shell
+(gdb) c
+coroutine [1] create
+main coroutine
+Continuing.
+
+Breakpoint 1, zim_study_coroutine_util_resume (execute_data=0x7ffff761d110, return_value=0x7fffffffb0b0) at /root/codeDir/cppCode/study/study_coroutine_util.cc:45
+(gdb) 
+```
+
+我们再继续执行：
+
+```shell
+(gdb) c
+Continuing.
+coroutine [2] create
+main coroutine
+
+Breakpoint 1, zim_study_coroutine_util_resume (execute_data=0x7ffff761d110, return_value=0x7fffffffb0b0) at /root/codeDir/cppCode/study/study_coroutine_util.cc:45
+(gdb) 
+```
+
+```shell
+44│ PHP_METHOD(study_coroutine_util, resume)
+45├>{
+46│     zend_long cid = 0;
+47│
+48│     ZEND_PARSE_PARAMETERS_START(1, 1)
+49│         Z_PARAM_LONG(cid)
+50│     ZEND_PARSE_PARAMETERS_END_EX(RETURN_FALSE);
+51│
+52│     auto coroutine_iterator = user_yield_coros.find(cid);
+53│
+54│     Coroutine* co = coroutine_iterator->second;
+55│     user_yield_coros.erase(cid);
+56│     co->resume();
+57│     RETURN_TRUE;
+```
+
+OK，这个时候，停在了最后一行代码：
+
+```php
+Study\Coroutine::resume($cid2);
+```
+
+里面了。
+
+我们执行到`54`行之前（不会执行54行的代码），这是报错的地方：
+
+```shell
+(gdb) u 54
+zim_study_coroutine_util_resume (execute_data=0x7ffff761d110, return_value=0x7fffffffb0b0) at /root/codeDir/cppCode/study/study_coroutine_util.cc:54
+(gdb) 
+```
+
+```shell
+52│     auto coroutine_iterator = user_yield_coros.find(cid);
+53│
+54├───> Coroutine* co = coroutine_iterator->second;
+55│     user_yield_coros.erase(cid);
+56│     co->resume();
+57│     RETURN_TRUE;
+58│ }
+```
+
+此时，我们打印`coroutine_iterator`的值：
+
+```shell
+(gdb) p coroutine_iterator
+$2 = {<std::__detail::_Node_iterator_base<std::pair<long const, Study::Coroutine*>, false>> = {_M_cur = 0x0}, <No data fields>}
+(gdb) 
+```
+
+发现`_M_cur = 0x0`，所以是没有取出东西来。
+
+没有取出东西来的原因是我们在每次`resume`一个协程的时候，会把对应的协程从`user_yield_coros`里面删除，所以我们接着第二次`resume`这个协程的时候，就无法找到这个协程了。除非在第二次`resume`这个协程之前，又`yield`这个协程了，重新把这个协程添加进去了`user_yield_coros`里面。
+
+所以，这里我们需要对`coroutine_iterator`进行判断。我们修改一下`PHP_METHOD(study_coroutine_util, resume)`这个接口：
+
+```cpp
+if (coroutine_iterator == user_yield_coros.end())
+{
+    php_error_docref(NULL, E_WARNING, "resume error");
+    RETURN_FALSE;
+}
+```
+
+OK，我们编译、安装：
+
+```shell
+make clean && make && make install
+```
+
+然后在执行脚本：
+
+```shell
+~/codeDir/cppCode/study # php test.php 
+main coroutine
+coroutine [1] create
+main coroutine
+coroutine [2] create
+main coroutine
+coroutine [1] create
+main coroutine
+coroutine [2] create
+main coroutine
+
+Warning: Study\Coroutine::resume(): resume error in /root/codeDir/cppCode/study/test.php on line 21
+~/codeDir/cppCode/study # 
+```
+
+OK，我们成功的报出了`Warning`，不至于让脚本因为无法`resume`一个协程而停止执行
+
+
+
+
+
+
+
+
+

docs/《PHP扩展开发》-协程-协程getCid.md

@@ -154,6 +154,8 @@ main coroutine
 
 符合预期。
 
+[下一篇：修复一些bug（一）](./《PHP扩展开发》-协程-修复一些bug（一）.md)
+
 
 
 

study_coroutine_util.cc

@@ -50,6 +50,11 @@ PHP_METHOD(study_coroutine_util, resume)
     ZEND_PARSE_PARAMETERS_END_EX(RETURN_FALSE);
 
     auto coroutine_iterator = user_yield_coros.find(cid);
+    if (coroutine_iterator == user_yield_coros.end())
+    {
+        php_error_docref(NULL, E_WARNING, "resume error");
+        RETURN_FALSE;
+    }
 
     Coroutine* co = coroutine_iterator->second;
     user_yield_coros.erase(cid);

test.php

@@ -17,4 +17,6 @@ echo "main coroutine" . PHP_EOL;
 Study\Coroutine::resume($cid1);
 echo "main coroutine" . PHP_EOL;
 Study\Coroutine::resume($cid2);
-echo "main coroutine" . PHP_EOL;
\ No newline at end of file
+echo "main coroutine" . PHP_EOL;
+Study\Coroutine::resume($cid2);
+echo "main coroutine" . PHP_EOL;