HiChecker is a framework provided by OpenHarmony for checking code errors and runtime results. It can be used for checking runtime errors during application and system development. This section applies only to the standard system.
## Development Guidelines
### Use Cases
HiChecker is provided for you to check issues that may be easily ignored during development of OpenHarmony applications (including system-built and third-party applications). Such issues include calling of time-consuming functions by key application threads, event distribution and execution timeout in application processes, and ability resource leakage in application processes. The issues are recorded in logs or lead to process crashes explicitly so that you can notice them and take correction measures.
### Available APIs
HiChecker provides the APIs listed in the following table.
**Table 1** HiChecker APIs
| **API**| **Description**|
| -------- | -------- |
| uint_64_t RULE_CAUTION_PRINT_LOG<br>= 1<<63; | Defines an alarm rule, which is programmed to record a log when an alarm is generated.|
| uint_64_t RULE_CAUTION_TRIGGER_CRASH = 1<<62; | Defines an alarm rule, which is programmed to force the application to exit when an alarm is generated.|
| uint_64_t RULE_THREAD_CHECK_SLOW_PROCESS = 1; | Defines a check rule, which is programmed to check whether any time-consuming function is called.|
| uint_64_t RULE_CHECK_SLOW_EVENT = 1<<32; | Defines a check rule, which is programmed to check whether the event distribution or processing time has exceeded the specified time threshold.|
| uint_64_t RULE_CHECK_ABILITY_CONNECTION_LEAK = 1<<33; | Defines a check rule, which is programmed to check ability leakage.|
| AddRule(uint_64_t rule) : void | Adds one or more rules. HiChecker detects unexpected operations or gives feedback based on the added rules.|
| RemoveRule(uint_64_t rule) : void | Removes one or more rules. The removed rules will no longer take effect.|
| GetRule() : uint_64_t | Obtains a collection of thread, process, and alarm rules that have been added.|
| Contains(uint_64_t rule) : bool | Checks whether the collection of added rules contains a specific rule. If a thread-level rule is specified, the system only checks whether it is contained in the current thread.|
| NotifySlowProcess(std::string tag) : void | Notifies your application of a slow process so that your application avoids calling it directly in key threads.|
| NotifySlowEvent(std::string tag) : void | Notifies your application that event distribution or execution has timed out.|
| NotifyAbilityConnectionLeak(Caution caution) : void | Notifies your application that AbilityConnection leakage has occurred.|
| GetTriggerRule() : uint_64_t | Obtains the rule that triggers the current alarm.|
| GetCautionMsg() : std::string | Obtains the alarm message.|
| GetStackTrace() : std::string | Obtains the stack when an alarm is triggered.|
### Development Example
C++
1. Include the following HiChecker header file in the code file:
```
#include "hichecker.h"
```
For a non-DFX subsystem, add the **HiviewDFX** field.
```
using namespace OHOS::HiviewDFX;
```
Use related APIs through static calls.
```
HiChecker::AddRule(Rule::RULE_THREAD_CHECK_SLOW_PROCESS); // Add a rule.
Notifies your application that AbilityConnection leakage has occurred. The following example shows that a **Caution** instance is passed into this API.
HiDumper is a tool provided by OpenHarmony for developers, testers, and IDE tool engineers to obtain system information necessary for analyzing and locating faults. This section applies only to the standard system.
### Source Code Directories
```
/base/hiviewdfx/hidumper
├── frameworks # Framework code
│ ├── native # Core function code
│ │ │── include # Header files
│ │ │── src # Source files
│ │ │── common # Common function code
│ │ │── executor # Process executor code
│ │ │── factory # Factory code
│ │ │── manager # Core manager code
│ │ │── util # Utility source code
│── sa_profile # HiDumper SA profile
│── services # HiDumper service code
│ │── native # C++ service code
│ │── zidl # Communication function
│ │ │── include # Header files of the communication function
│ │ │── src # Source code of the communication function
├── test # Test cases
│ ├── unittest # Unit test code
│ ├── moduletest # Module-level test code
```
## Usage
### Command-Line Options
**Table 1** HiDumper command-line options
| Option| Description|
| -------- | -------- |
| -h | Shows the help Information.|
| -t [timeout] | Specifies the timeout period, in seconds. The default value is **30**. Value **0** indicates no timeout limit.|
| -lc | Shows the system information cluster list.|
| -ls | Shows the system ability list.|
| -c | Exports system cluster information.|
| -c [base system] | Exports system cluster information based on **base** or **system** tags.|
| -s | Exports all system ability information.|
| -s [SA0 SA1] | Exports ability information corresponding to SA0 and SA1.|
| -s [SA] -a ['-h'] | Exports the system ability information **SA** using the **-h** parameter.|
| -e | Exports crash logs generated by the FaultLogger module.|
| --net | Exports network information.|
| --storage | Exports storage information.|
| -p | Exports the process list and all process information.|
| -p [pid] | Exports all information about a specified process.|
| --cpuusage [pid] | Exports the CPU usage information based on **pid**.|
| --cpufreq | Exports the actual CPU frequency.|
| --mem [pid] | Exports the memory usage information based on **pid**.|
| --zip | Compresses the exported information to a specified folder.|
### Development Example
HiDumper helps you export basic system information to locate and analyze faults. Complex parameters passed to sub-services and abilities must be enclosed in double quotation marks.
The procedure is as follows:
1. Access the device CLI, and run the **hidumper -h** command to obtain the help information, which includes basic information and function syntax.
```
hidumper -h
```
2. Run the **hidumper -lc** command to obtain the system information cluster list.
```
hidumper -lc
```
3. Run the **hidumper -c** command to obtain all information that is classified by **base** and **system**.
```
hidumper -c
```
4. Run the **hidumper -c [base | system]** to obtain the system cluster information that is classified by **base** or **system**.
```
hidumper -c base
hidumper -c system
```
5. Run the **hidumper -ls** command to obtain the system ability list.
```
hidumper -ls
```
6. Run the **hidumper -s** command to obtain all system ability information.
```
hidumper -s
```
7. Run the **hidumper -s 3301 -a "-h"** command to obtain the help information about the ability whose ID is **3301**.
```
hidumper -s 3301 -a "-h"
```
8. Run the **hidumper -s 3008** command to obtain all information about the ability whose ID is **3008**.
```
hidumper -s 3008
```
9. Run the **hidumper -e** command to obtain the crash information generated by the FaultLogger module.
```
hidumper -e
```
10. Run the **hidumper --net** command to obtain network information.
```
hidumper --net
```
11. Run the **hidumper --storage** command to obtain storage information.
```
hidumper --storage
```
12. Run the **hidumper -p** command to obtain process information, including the list and information of processes and threads.
```
hidumper -p
```
13. Run the **hidumper -p 1024** command to obtain information about the process whose PID is **1024**.
```
hidumper -p 1024
```
14. Run the **hidumper --cpuusage [pid]** command to obtain the CPU usage information of the process whose PID has been specified.
```
hidumper --cpuusage
hidumper --cpuusage 1024
```
15. Run the **hidumper --cpufreq** command to obtain the actual operating frequency of each CPU core.
```
hidumper --cpufreq
```
16. Run the **hidumper --mem [pid]** command to obtain all memory usage information of the process whose PID has been specified.
```
hidumper --mem [pid]
```
17. Run the **hidumper --zip** command to compress data to the **/data/dumper** directory.
```
hidumper --zip
```
18. Run the **hidumper -t timeout** command to set the timeout period, in seconds. The default value is **30**. Value **0** indicates no timeout limit.
@@ -31,4 +34,3 @@ Event logging means to collect and log events reported during system running. Th
**System event**
A system event is an indication of the system status at a given time point during system running. You can use these events to analyze the status change of the system.
