Kontinuation commented on code in PR #678: URL: https://github.com/apache/sedona-db/pull/678#discussion_r2878678645
########## c/sedona-gdal/src/vsi.rs: ########## @@ -0,0 +1,177 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! GDAL Virtual File System (VSI) wrappers. + +use std::ffi::CString; + +use crate::errors::{GdalError, Result}; +use crate::gdal_api::{call_gdal_api, GdalApi}; + +/// Creates a new VSI in-memory file from a given buffer. +/// +/// The data is copied into GDAL-allocated memory (via `VSIMalloc`) so that +/// GDAL can safely free it with `VSIFree` when ownership is taken. +pub fn create_mem_file(api: &'static GdalApi, file_name: &str, data: Vec<u8>) -> Result<()> { + let c_file_name = CString::new(file_name)?; + let len = data.len(); + + // Allocate via GDAL's allocator so GDAL can safely free it. + let gdal_buf = unsafe { call_gdal_api!(api, VSIMalloc, len) } as *mut u8; + if gdal_buf.is_null() { + return Err(GdalError::NullPointer { + method_name: "VSIMalloc", + msg: format!("failed to allocate {len} bytes"), + }); + } + + // Copy data into GDAL-allocated buffer + unsafe { + std::ptr::copy_nonoverlapping(data.as_ptr(), gdal_buf, len); + } + // Rust Vec is dropped here, freeing the Rust-allocated memory. + + let handle = unsafe { + call_gdal_api!( + api, + VSIFileFromMemBuffer, + c_file_name.as_ptr(), + gdal_buf, + len as i64, + 1 // bTakeOwnership = true — GDAL will VSIFree gdal_buf + ) + }; + + if handle.is_null() { + // GDAL did not take ownership, so we must free. + unsafe { call_gdal_api!(api, VSIFree, gdal_buf as *mut std::ffi::c_void) }; + return Err(GdalError::NullPointer { + method_name: "VSIFileFromMemBuffer", + msg: String::new(), + }); + } + + unsafe { + call_gdal_api!(api, VSIFCloseL, handle); + } + + Ok(()) +} + +/// Unlink (delete) a VSI in-memory file. +pub fn unlink_mem_file(api: &'static GdalApi, file_name: &str) -> Result<()> { + let c_file_name = CString::new(file_name)?; + + let rv = unsafe { call_gdal_api!(api, VSIUnlink, c_file_name.as_ptr()) }; + + if rv != 0 { + return Err(GdalError::UnlinkMemFile { + file_name: file_name.to_string(), + }); + } + + Ok(()) +} + +/// Copies the bytes of the VSI in-memory file, taking ownership and freeing the GDAL memory. +pub fn get_vsi_mem_file_bytes_owned(api: &'static GdalApi, file_name: &str) -> Result<Vec<u8>> { + let c_file_name = CString::new(file_name)?; + + let owned_bytes = unsafe { + let mut length: i64 = 0; + let bytes = call_gdal_api!( + api, + VSIGetMemFileBuffer, + c_file_name.as_ptr(), + &mut length, + 1 // bUnlinkAndSeize = true + ); + + if bytes.is_null() { + return Err(GdalError::NullPointer { + method_name: "VSIGetMemFileBuffer", + msg: String::new(), + }); + } + + if length < 0 { + call_gdal_api!(api, VSIFree, bytes.cast::<std::ffi::c_void>()); + return Err(GdalError::BadArgument(format!( + "VSIGetMemFileBuffer returned negative length: {length}" + ))); + } + + let slice = std::slice::from_raw_parts(bytes, length as usize); + let vec = slice.to_vec(); + + call_gdal_api!(api, VSIFree, bytes.cast::<std::ffi::c_void>()); + + vec + }; + + Ok(owned_bytes) +} + +#[cfg(all(test, feature = "gdal-sys"))] +mod tests { + use super::*; + use crate::register::get_global_gdal_api; + + #[test] + fn create_and_retrieve_mem_file() { + let file_name = "/vsimem/525ebf24-a030-4677-bb4e-a921741cabe0"; + + let api = get_global_gdal_api().unwrap(); + create_mem_file(api, file_name, vec![1_u8, 2, 3, 4]).unwrap(); + + let bytes = get_vsi_mem_file_bytes_owned(api, file_name).unwrap(); + + assert_eq!(bytes, vec![1_u8, 2, 3, 4]); + + // mem file must not be there anymore + assert!(matches!( + unlink_mem_file(api, file_name).unwrap_err(), + GdalError::UnlinkMemFile { + file_name + } + if file_name == file_name Review Comment: Fixed -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
