j2k-cuda-runtime 0.7.0

// SPDX-License-Identifier: MIT OR Apache-2.0

use std::{
    collections::HashMap,
    sync::{Arc, Mutex},
};

use crate::{driver::Driver, error::CudaError, memory::PinnedUploadStagingPool};

use super::host_budget::SharedCudaHostBudget;
use super::{inner::ContextInner, ContextResourceLifecycle, CudaContext};

impl CudaContext {
    /// Create a context for the system default CUDA device.
    pub fn system_default() -> Result<Self, CudaError> {
        let driver = Driver::load()?;

        // SAFETY: cuInit is the CUDA Driver API process initializer.
        driver.check("cuInit", unsafe { (driver.cu_init)(0) })?;

        let mut count = 0;
        // SAFETY: CUDA writes one integer device count to the provided pointer.
        driver.check("cuDeviceGetCount", unsafe {
            (driver.cu_device_get_count)(&raw mut count)
        })?;
        if count <= 0 {
            return Err(CudaError::Unavailable {
                message: "no CUDA devices reported by driver".to_string(),
            });
        }

        let mut device = 0;
        // SAFETY: device 0 is valid when count is greater than zero.
        driver.check("cuDeviceGet", unsafe {
            (driver.cu_device_get)(&raw mut device, 0)
        })?;

        let mut context = std::ptr::null_mut();
        // SAFETY: CUDA writes a newly-created context handle for a valid device.
        driver.check("cuCtxCreate_v2", unsafe {
            (driver.cu_ctx_create)(&raw mut context, 0, device)
        })?;
        super::validate_resource_handle(
            context,
            "CUDA returned a null context after successful creation",
        )?;

        Ok(Self {
            inner: Arc::new(ContextInner {
                driver,
                context,
                modules: Mutex::new(HashMap::new()),
                pinned_upload_operation: Mutex::new(()),
                pinned_upload_staging: Mutex::new(PinnedUploadStagingPool::new()),
                host_budget: SharedCudaHostBudget::new(),
                resource_lifecycle: ContextResourceLifecycle::new(),
            }),
        })
    }
}