libv8js_example

Repository provides examples of how to solve some tasks in C++ using v8 library.

Dependencies

The following libraries are required to be installed:

libopenssl
V8 # Completed build of V8 libraries can be find in the repository.

Building from source

git clone https://github.com/metahashorg/vm_v8

cd vm_8
cd build
./build.sh

/src directory contains built vm_v8 utility. Before launching the utility, it is needed to run the following command:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:src/v8/lib

Features

1. Output of the bytecode:

./vm_v8 -mode bt -js [js file path]

2. Counting the number of instructions:

./vm_v8 -mode btcount -js [js file path]

3. Memory footprint:

./vm_v8 -mode mem -js [js file path]

4. Testing external variable:

./vm_v8 -mode external -intarg [integer]

5. sha256:

./vm_v8 -mode sha256 -strarg [string]

6. Signature check:

./vm_v8 -mode sig

7. Generating address on public key:

./vm_v8 -mode newaddr -strarg [public key in the form of hex string]

8. Compiler test:

 ./vm_v8 -mode compile -a ADDR -js FILE.JS

9. Initialization status:

./vm_v8 -mode run -a ADDR -cmd run.js -js FILE.JS -cmpl FILE.cmpl -snap_o I_FILE.shot

10. Status dump:

./vm_v8 -mode run -a ADDR -cmd run.js -snap_i I_FILE.shot -snap_o I_FILE.shot

Initialization and contract status dump test.

ADDR — address of the contract

FILE.JS — file containing core js code. When running contract initialization test there is a contract code (contract.js).

FILE.cmpl — file containing compiler cache, is equal to FILE.js.

run.js - file containing js code, that conducts one of 2 operations, i.e. initialization or status dump (init.js and dump.js)

I_FILE.shot - input file of the virtual machine memory snapshot, it is mandatory for the status test and optional for the initialization test.

I_FILE.shot — file containing memory snapshot after core code and command code

Following files are added to the project:

contract.js
contract.cmpl
init.js
dump.js

Command line for running initialization test:

./vm_v8 -mode run -a 0xaddress -cmd init.js -js contract.js -cmpl contract.cmpl -snap_o init.shot

Output:

snapshot init.shot Entry in the err.log file shows that contract has been initialized successfully: ContractStateTest:[object Object]

Running status dump test:

./test -mode run -a 0xaddress -cmd dump.js -snap_i init.shot -snap_o result.shot

Output:

Final snapshot result.shot.

Entry in the err.log file regarding contract status:

ContractStateTest:
{ "items":
  [
    {
      "key":"ammount",
      "type":"number",
      "value":220
    },
    {
      "key":"data",
      "type":"Map",
      "value":
      [
        ["Jane",100],["Bob",120]
      ]
    }
  ]
}