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Update proj::Proj constructors to return Result instead of Option. #98

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merged 1 commit into from
Feb 4, 2022
Merged

Update proj::Proj constructors to return Result instead of Option. #98

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1 change: 1 addition & 0 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -217,5 +217,6 @@ pub use crate::proj::Coord;
pub use crate::proj::Info;
pub use crate::proj::Proj;
pub use crate::proj::ProjBuilder;
pub use crate::proj::ProjCreateError;
pub use crate::proj::ProjError;
pub use crate::proj::Projinfo;
119 changes: 97 additions & 22 deletions src/proj.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,14 +3,18 @@ use libc::{c_char, c_double};
use num_traits::Float;
use proj_sys::{
proj_area_create, proj_area_destroy, proj_area_set_bbox, proj_cleanup, proj_context_create,
proj_context_destroy, proj_context_get_url_endpoint, proj_context_is_network_enabled,
proj_context_set_search_paths, proj_context_set_url_endpoint, proj_create,
proj_create_crs_to_crs, proj_destroy, proj_errno_string, proj_get_area_of_use,
proj_context_destroy, proj_context_errno, proj_context_get_url_endpoint,
proj_context_is_network_enabled, proj_context_set_search_paths, proj_context_set_url_endpoint,
proj_create, proj_create_crs_to_crs, proj_destroy, proj_errno_string, proj_get_area_of_use,
proj_grid_cache_set_enable, proj_info, proj_normalize_for_visualization, proj_pj_info,
proj_trans, proj_trans_array, PJconsts, PJ_AREA, PJ_CONTEXT, PJ_COORD, PJ_DIRECTION_PJ_FWD,
PJ_DIRECTION_PJ_INV, PJ_INFO, PJ_LP, PJ_XY,
};
use std::fmt::{self, Debug};
use std::{
ffi,
fmt::{self, Debug},
str,
};

#[cfg(feature = "network")]
use proj_sys::proj_context_set_enable_network;
Expand All @@ -21,7 +25,6 @@ use std::ffi::CStr;
use std::ffi::CString;
use std::mem::MaybeUninit;
use std::path::Path;
use std::str;
use thiserror::Error;

pub trait CoordinateType: Float + Copy + PartialOrd + Debug {}
Expand Down Expand Up @@ -96,6 +99,16 @@ pub enum ProjError {
DownloadError(String, String, u8),
}

#[derive(Error, Debug)]
pub enum ProjCreateError {
#[error("A nul byte was found in the PROJ string definition or CRS argument: {0}")]
ArgumentNulError(ffi::NulError),
#[error("The underlying PROJ call failed: {0}")]
ProjError(String),
#[error("A UTF8 error occurred when constructing a PROJ error message")]
ProjErrorMessageUtf8Error(std::str::Utf8Error),
}

/// The bounding box of an area of use
///
/// In the case of an area of use crossing the antimeridian (longitude +/- 180 degrees),
Expand Down Expand Up @@ -124,14 +137,14 @@ impl Area {
}

/// Easily get a String from the external library
pub(crate) unsafe fn _string(raw_ptr: *const c_char) -> Result<String, ProjError> {
pub(crate) unsafe fn _string(raw_ptr: *const c_char) -> Result<String, str::Utf8Error> {
assert!(!raw_ptr.is_null());
let c_str = CStr::from_ptr(raw_ptr);
Ok(str::from_utf8(c_str.to_bytes())?.to_string())
}

/// Look up an error message using the error code
fn error_message(code: c_int) -> Result<String, ProjError> {
fn error_message(code: c_int) -> Result<String, str::Utf8Error> {
unsafe {
let rv = proj_errno_string(code);
_string(rv)
Expand All @@ -149,13 +162,17 @@ fn area_set_bbox(parea: *mut proj_sys::PJ_AREA, new_area: Option<Area>) {
}

/// called by Proj::new and ProjBuilder::transform_new_crs
fn transform_string(ctx: *mut PJ_CONTEXT, definition: &str) -> Option<Proj> {
let c_definition = CString::new(definition).ok()?;
fn transform_string(ctx: *mut PJ_CONTEXT, definition: &str) -> Result<Proj, ProjCreateError> {
let c_definition =
CString::new(definition).map_err(|e| ProjCreateError::ArgumentNulError(e))?;
let new_c_proj = unsafe { proj_create(ctx, c_definition.as_ptr()) };
if new_c_proj.is_null() {
None
let error_code = unsafe { proj_context_errno(ctx) };
let message =
error_message(error_code).map_err(|e| ProjCreateError::ProjErrorMessageUtf8Error(e))?;
Err(ProjCreateError::ProjError(message))
} else {
Some(Proj {
Ok(Proj {
c_proj: new_c_proj,
ctx,
area: None,
Expand All @@ -164,15 +181,23 @@ fn transform_string(ctx: *mut PJ_CONTEXT, definition: &str) -> Option<Proj> {
}

/// Called by new_known_crs and proj_known_crs
fn transform_epsg(ctx: *mut PJ_CONTEXT, from: &str, to: &str, area: Option<Area>) -> Option<Proj> {
let from_c = CString::new(from).ok()?;
let to_c = CString::new(to).ok()?;
fn transform_epsg(
ctx: *mut PJ_CONTEXT,
from: &str,
to: &str,
area: Option<Area>,
) -> Result<Proj, ProjCreateError> {
let from_c = CString::new(from).map_err(|e| ProjCreateError::ArgumentNulError(e))?;
let to_c = CString::new(to).map_err(|e| ProjCreateError::ArgumentNulError(e))?;
let proj_area = unsafe { proj_area_create() };
area_set_bbox(proj_area, area);
let new_c_proj =
unsafe { proj_create_crs_to_crs(ctx, from_c.as_ptr(), to_c.as_ptr(), proj_area) };
if new_c_proj.is_null() {
None
let error_code = unsafe { proj_context_errno(ctx) };
let message =
error_message(error_code).map_err(|e| ProjCreateError::ProjErrorMessageUtf8Error(e))?;
Err(ProjCreateError::ProjError(message))
} else {
// Normalise input and output order to Lon, Lat / Easting Northing by inserting
// An axis swap operation if necessary
Expand All @@ -182,7 +207,7 @@ fn transform_epsg(ctx: *mut PJ_CONTEXT, from: &str, to: &str, area: Option<Area>
proj_destroy(new_c_proj);
normalised
};
Some(Proj {
Ok(Proj {
c_proj: normalised,
ctx,
area: Some(proj_area),
Expand Down Expand Up @@ -226,7 +251,7 @@ pub trait Info {
/// # Safety
/// This method contains unsafe code.
fn get_url_endpoint(&self) -> Result<String, ProjError> {
unsafe { _string(proj_context_get_url_endpoint(self.ctx())) }
Ok(unsafe { _string(proj_context_get_url_endpoint(self.ctx()))? })
}
}

Expand Down Expand Up @@ -365,7 +390,7 @@ impl ProjBuilder {
///
/// # Safety
/// This method contains unsafe code.
pub fn proj(mut self, definition: &str) -> Option<Proj> {
pub fn proj(mut self, definition: &str) -> Result<Proj, ProjCreateError> {
let ctx = unsafe { std::mem::replace(&mut self.ctx, proj_context_create()) };
transform_string(ctx, definition)
}
Expand Down Expand Up @@ -408,7 +433,12 @@ impl ProjBuilder {
///
/// # Safety
/// This method contains unsafe code.
pub fn proj_known_crs(mut self, from: &str, to: &str, area: Option<Area>) -> Option<Proj> {
pub fn proj_known_crs(
mut self,
from: &str,
to: &str,
area: Option<Area>,
) -> Result<Proj, ProjCreateError> {
let ctx = unsafe { std::mem::replace(&mut self.ctx, proj_context_create()) };
transform_epsg(ctx, from, to, area)
}
Expand Down Expand Up @@ -443,7 +473,7 @@ impl Proj {
// is signalled by the choice of enum used as input to the PJ_COORD union
// PJ_LP signals projection of geodetic coordinates, with output being PJ_XY
// and vice versa, or using PJ_XY for conversion operations
pub fn new(definition: &str) -> Option<Proj> {
pub fn new(definition: &str) -> Result<Proj, ProjCreateError> {
let ctx = unsafe { proj_context_create() };
transform_string(ctx, definition)
}
Expand Down Expand Up @@ -486,7 +516,11 @@ impl Proj {
///
/// # Safety
/// This method contains unsafe code.
pub fn new_known_crs(from: &str, to: &str, area: Option<Area>) -> Option<Proj> {
pub fn new_known_crs(
from: &str,
to: &str,
area: Option<Area>,
) -> Result<Proj, ProjCreateError> {
let ctx = unsafe { proj_context_create() };
transform_epsg(ctx, from, to, area)
}
Expand Down Expand Up @@ -1039,6 +1073,33 @@ mod test {
assert_relative_eq!(t.x(), 1450880.2910605022);
assert_relative_eq!(t.y(), 1141263.0111604782);
}

#[test]
fn test_from_crs_nul_error() {
match Proj::new_known_crs("\0", "EPSG:4326", None) {
Err(ProjCreateError::ArgumentNulError(_)) => (),
_ => unreachable!(),
}

match Proj::new_known_crs("EPSG:4326", "\0", None) {
Err(ProjCreateError::ArgumentNulError(_)) => (),
_ => unreachable!(),
}
}

#[test]
fn test_from_crs_error() {
match Proj::new_known_crs("EPSG:4326", "🦀", None) {
Err(ProjCreateError::ProjError(..)) => (),
_ => unreachable!(),
}

match Proj::new_known_crs("🦀", "EPSG:4326", None) {
Err(ProjCreateError::ProjError(..)) => (),
_ => unreachable!(),
}
}

#[test]
// Carry out a projection from geodetic coordinates
fn test_projection() {
Expand Down Expand Up @@ -1107,11 +1168,25 @@ mod test {
assert_relative_eq!(t.x(), 1450880.2910605022);
assert_relative_eq!(t.y(), 1141263.0111604782);
}

#[test]
// Test that instantiation fails wth bad proj string input
fn test_init_error() {
assert!(Proj::new("🦀").is_none());
match Proj::new("🦀") {
Err(ProjCreateError::ProjError(_)) => (),
_ => unreachable!(),
}
}

#[test]
// Test that instantiation fails wth bad proj string input
fn test_init_error_nul() {
match Proj::new("\0") {
Err(ProjCreateError::ArgumentNulError(_)) => (),
_ => unreachable!(),
}
}

#[test]
fn test_conversion_error() {
// because step 1 isn't an inverse conversion, it's expecting lon lat input
Expand Down