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denoland-rusty-v8/examples/hello_world.rs
Daniel Bevenius b1d31c7d76
Add dispose/shutdown_platform to hello_world (#532)
This commit adds calls to v8::V8::dispose and v8::V8::shutdown_platform
to the hello_world.rs example.

The motivation for adding this is that it was not obvious to me that I
needed to have the Isolate in a separate scope. If there is not, the
platform will have been shutdown before the Isolate's Drop function
is called at the end of the function where the scope ends. Drop will in
turn call Dispose on the V8 Isolate, which calls Isolate::Deinit, and
Deinit calls tracing_cpu_profilers.reset() which will call
~TracingCpuProfilerImpl which has a call to V8::GetCurrentPlatform()
which will produce the following error:

 Fatal error in ../../../v8/src/init/v8.cc, line 144
 Debug check failed: platform.

 FailureMessage Object: 0x7fff45b03700Illegal instruction (core dumped)

Having an example might safe others some time if they run into the same
issue.
2020-11-19 12:26:45 +01:00

72 lines
2.4 KiB
Rust

use rusty_v8 as v8;
fn main() {
// Initialize V8.
let platform = v8::new_default_platform().unwrap();
v8::V8::initialize_platform(platform);
v8::V8::initialize();
{
// Create a new Isolate and make it the current one.
let isolate = &mut v8::Isolate::new(v8::CreateParams::default());
// Create a stack-allocated handle scope.
let handle_scope = &mut v8::HandleScope::new(isolate);
// Create a new context.
let context = v8::Context::new(handle_scope);
// Enter the context for compiling and running the hello world script.
let scope = &mut v8::ContextScope::new(handle_scope, context);
// Create a string containing the JavaScript source code.
let code = v8::String::new(scope, "'Hello' + ' World!'").unwrap();
// Compile the source code.
let script = v8::Script::compile(scope, code, None).unwrap();
// Run the script to get the result.
let result = script.run(scope).unwrap();
// Convert the result to a string and print it.
let result = result.to_string(scope).unwrap();
println!("{}", result.to_rust_string_lossy(scope));
// Use the JavaScript API to generate a WebAssembly module.
//
// |bytes| contains the binary format for the following module:
//
// (func (export "add") (param i32 i32) (result i32)
// get_local 0
// get_local 1
// i32.add)
//
let c_source = r#"
let bytes = new Uint8Array([
0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00, 0x01, 0x07, 0x01,
0x60, 0x02, 0x7f, 0x7f, 0x01, 0x7f, 0x03, 0x02, 0x01, 0x00, 0x07,
0x07, 0x01, 0x03, 0x61, 0x64, 0x64, 0x00, 0x00, 0x0a, 0x09, 0x01,
0x07, 0x00, 0x20, 0x00, 0x20, 0x01, 0x6a, 0x0b
]);
let module = new WebAssembly.Module(bytes);
let instance = new WebAssembly.Instance(module);
instance.exports.add(3, 4);
"#;
// Create a string containing the JavaScript source code.
let source = v8::String::new(scope, c_source).unwrap();
// Compile the source code.
let script = v8::Script::compile(scope, source, None).unwrap();
// Run the script to get the result.
let result = script.run(scope).unwrap();
// Print the result.
let result = result.to_uint32(scope).unwrap();
println!("3 + 4 = {}", result.value());
}
unsafe {
v8::V8::dispose();
}
v8::V8::shutdown_platform();
}