Merge #281

281: Fix crate build on docs.rs r=rmanoka a=rmanoka

Use dynamic code-gen to build-around non-availabiltiy of some packages.

- [X] I agree to follow the project's [code of conduct](https://github.com/georust/gdal/blob/master/CODE_OF_CONDUCT.md).
- [X] I added an entry to `CHANGES.md` if knowledge of this change could be valuable to users.
---



Co-authored-by: Rajsekar Manokaran <[email protected]>

CHANGES.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- Add prebuild bindings for GDAL 3.5
+  - <https://github.com/georust/gdal/pull/277>
+
 - **Breaking**: Add `gdal::vector::OwnedLayer`, `gdal::vector::LayerAccess` and `gdal::vector::layer::OwnedFeatureIterator`. This requires importing `gdal::vector::LayerAccess` for using most vector layer methods.
 
   - https://github.com/georust/gdal/pull/238

Cargo.toml

@@ -35,6 +35,3 @@ trybuild = "1.0"
 
 [workspace]
 members = ["gdal-sys"]
-
-[package.metadata.docs.rs]
-rustc-args = ["--cfg", "docsrs"]

build.rs

@@ -1,23 +1,11 @@
 use std::str::FromStr;
 
-#[cfg(docsrs)]
-pub fn gdal_version_info(_key: &str) -> String {
-    "3020000".to_string()
-}
-
-#[cfg(not(docsrs))]
-pub fn gdal_version_info(key: &str) -> String {
-    let c_key = std::ffi::CString::new(key.as_bytes()).unwrap();
-
-    unsafe {
-        let res_ptr = gdal_sys::GDALVersionInfo(c_key.as_ptr());
-        let c_res = std::ffi::CStr::from_ptr(res_ptr);
-        c_res.to_string_lossy().into_owned()
-    }
+fn gdal_version_info() -> String {
+    gdal_sys::gdal_version_docs_rs_wrapper()
 }
 
 fn main() {
-    let gdal_version_string = gdal_version_info("VERSION_NUM");
+    let gdal_version_string = gdal_version_info();
     println!("GDAL version string: \"{}\"", gdal_version_string);
 
     // this version string is the result of:

gdal-sys/build.rs

@@ -57,13 +57,40 @@ fn find_gdal_dll(lib_dir: &Path) -> io::Result<Option<String>> {
     Ok(None)
 }
 
+fn add_docs_rs_helper(version: Option<&str>) {
+    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("docs_rs_helper.rs");
+    let docs_helper_code = if let Some(version) = version {
+        format!(
+            r#"
+        pub fn gdal_version_docs_rs_wrapper() -> String {{
+            "{version}".to_string()
+        }}"#
+        )
+    } else {
+        r#"
+        pub fn gdal_version_docs_rs_wrapper() -> String {
+            let key = "VERSION_NUM";
+            let c_key = std::ffi::CString::new(key.as_bytes()).unwrap();
+
+            unsafe {
+                let res_ptr = crate::GDALVersionInfo(c_key.as_ptr());
+                let c_res = std::ffi::CStr::from_ptr(res_ptr);
+                c_res.to_string_lossy().into_owned()
+            }
+        }"#
+        .to_string()
+    };
+    std::fs::write(&out_path, docs_helper_code.as_bytes()).unwrap();
+}
+
 fn main() {
     let out_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("bindings.rs");
 
     // Hardcode a prebuilt binding version while generating docs.
     // Otherwise docs.rs will explode due to not actually having libgdal installed.
     if std::env::var("DOCS_RS").is_ok() {
-        let version = Version::parse("3.2.0").expect("invalid version for docs.rs");
+        let version = Version::parse("3.5.0").expect("invalid version for docs.rs");
+        add_docs_rs_helper(Some("3050000"));
         println!(
             "cargo:rustc-cfg=gdal_sys_{}_{}_{}",
             version.major, version.minor, version.patch
@@ -83,6 +110,7 @@ fn main() {
         return;
     }
 
+    add_docs_rs_helper(None);
     println!("cargo:rerun-if-env-changed=GDAL_STATIC");
     println!("cargo:rerun-if-env-changed=GDAL_DYNAMIC");
     println!("cargo:rerun-if-env-changed=GDAL_INCLUDE_DIR");

gdal-sys/src/lib.rs

@@ -4,3 +4,4 @@
 #![allow(clippy::upper_case_acronyms)]
 
 include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
+include!(concat!(env!("OUT_DIR"), "/docs_rs_helper.rs"));