Function ConsumeBytes

crates/bindings-cpp/src/internal/Module.cpp:389–449

Helper to consume all bytes from a BytesSource

// Helper to consume all bytes from a BytesSource
std::vector<uint8_t> ConsumeBytes(BytesSource source) {
    if (source.inner == 0) {
        return {};
    }
    
    // Take a buffer from the pool (typically 64 KiB pre-allocated)
    IterBuf iter_buf = IterBuf::take();
    
    // Get the remaining length to reserve exact buffer size
    uint32_t remaining_len = 0;
    auto ret = FFI::bytes_source_remaining_length(source, &remaining_len);
    if (ret != 0) {
        // If we can't get the length, fall back to incremental reading
        // This shouldn't happen with current host implementation
        constexpr size_t CHUNK_SIZE = 1024;
        iter_buf.reserve(CHUNK_SIZE);
        
        while (true) {
            size_t chunk_size = CHUNK_SIZE;
            size_t old_size = iter_buf.size();
            iter_buf.resize(old_size + chunk_size);
            
            ret = FFI::bytes_source_read(source, iter_buf.data() + old_size, &chunk_size);
            iter_buf.resize(old_size + chunk_size);  // Resize to actual bytes read
            
            if (ret == -1) {  // EXHAUSTED
                break;
            } else if (ret != 0) {  // Error
                fprintf(stderr, "ERROR: Failed to read from BytesSource: %d\n", ret);
                break;
            }
        }
        return iter_buf.release();
    }
    
    // Reserve exact size needed (often no-op since pool buffer is 64 KiB)
    iter_buf.resize(remaining_len);  // Resize to exact size BEFORE reading
    
    // Read all bytes - should complete in one call since we have capacity
    size_t bytes_read = 0;
    while (bytes_read < remaining_len) {
        size_t chunk_size = remaining_len - bytes_read;
        ret = FFI::bytes_source_read(source, iter_buf.data() + bytes_read, &chunk_size);
        bytes_read += chunk_size;
        
        if (ret == -1) {  // EXHAUSTED
            break;
        } else if (ret != 0) {  // Error
            fprintf(stderr, "ERROR: Failed to read from BytesSource: %d\n", ret);
            break;
        }
    }
    
    // Resize to actual bytes read if different (shouldn't normally happen)
    if (bytes_read != remaining_len) {
        iter_buf.resize(bytes_read);
    }