Merge pull request #216 from mulimoen/feature/weak_features

Use weak features in Cargo.toml

Author: aldanor

.github/workflows/ci.yml

@@ -46,7 +46,7 @@ jobs:
       - name: Document workspace
         env:
           RUSTDOCFLAGS: "--cfg docsrs"
-        run: cargo doc --features hdf5-sys/static,hdf5-sys/zlib,blosc,lzf
+        run: cargo doc --features static,zlib,blosc,lzf
 
   brew:
     name: brew

CHANGELOG.md

@@ -11,12 +11,18 @@
   datasets. Usage via `Dataset::as_byte_reader()`.
 - Add `chunk_visit` to visit all chunks in a dataset.
 - Implement `H5Type` for `num_complex::Complex`.
+- Adding feature `static` for the `hdf5` crate which downloads and builds a bundled HDF5.
 
 ### Changed
 
 - The `H5Type` derive macro now uses `proc-macro-error` to emit error messages.
 - MSRV is now `1.64.0` and Rust edition has now been bumped to 2021.
 - Types in ChunkInfo has been changed to match HDF5.
+- Dependencies now uses the `dep:` syntax and are only enabled through features.
+- Some features are made weak and will not enable e.g. static build when asking for a
+  library which is threadsafe.
+- Requesting a feature which is not compiled in the dynamic HDF5 library will
+  now cause a compile time error.
 
 ### Fixed
 

hdf5-src/Cargo.toml

@@ -30,7 +30,7 @@ edition.workspace = true
 
 [features]
 hl = []
-zlib = ["libz-sys"]
+zlib = ["dep:libz-sys"]
 deprecated = []
 threadsafe = []
 

hdf5-sys/Cargo.toml

@@ -23,12 +23,12 @@ hdf5-src = { workspace = true, optional = true }
 # Please see README for further explanation of these feature flags
 [features]
 default = []
-mpio = ["mpi-sys"]
-hl = ["hdf5-src/hl"]
-threadsafe = ["hdf5-src/threadsafe"]
-zlib = ["libz-sys", "hdf5-src/zlib"]
-static = ["hdf5-src"]
-deprecated = ["hdf5-src/deprecated"]
+mpio = ["dep:mpi-sys"]
+hl = ["hdf5-src?/hl"]
+threadsafe = ["hdf5-src?/threadsafe"]
+zlib = ["libz-sys", "hdf5-src?/zlib"]
+static = ["dep:hdf5-src"]
+deprecated = ["hdf5-src?/deprecated"]
 
 [build-dependencies]
 libloading = "0.8"

hdf5-sys/build.rs

@@ -175,6 +175,8 @@ pub struct Header {
     pub have_direct: bool,
     pub have_parallel: bool,
     pub have_threadsafe: bool,
+    pub have_zlib: bool,
+    pub have_no_deprecated: bool,
     pub version: Version,
 }
 
@@ -200,6 +202,10 @@ impl Header {
                 hdr.have_parallel = value > 0;
             } else if name == "H5_HAVE_THREADSAFE" {
                 hdr.have_threadsafe = value > 0;
+            } else if name == "H5_HAVE_FILTER_DEFLATE" {
+                hdr.have_zlib = value > 0;
+            } else if name == "H5_NO_DEPRECATED_SYMBOLS" {
+                hdr.have_no_deprecated = value > 0;
             }
         }
 
@@ -611,6 +617,7 @@ impl LibrarySearcher {
             if !(self.pkg_conf_found && cfg!(windows)) {
                 validate_runtime_version(&config);
             }
+            config.check_against_features_required();
             config
         } else {
             panic!("Unable to determine HDF5 location (set HDF5_DIR to specify it manually).");
@@ -675,6 +682,22 @@ impl Config {
             println!("cargo:have_threadsafe=1");
         }
     }
+
+    fn check_against_features_required(&self) {
+        let h = &self.header;
+        for (flag, feature, native) in [
+            (!h.have_no_deprecated, "deprecated", "HDF5_ENABLE_DEPRECATED_SYMBOLS"),
+            (h.have_threadsafe, "threadsafe", "HDF5_ENABLE_THREADSAFE"),
+            (h.have_zlib, "zlib", "HDF5_ENABLE_Z_LIB_SUPPORT"),
+        ] {
+            if feature_enabled(&feature.to_ascii_uppercase()) {
+                assert!(
+                    flag,
+                    "Enabled feature {feature:?} but the HDF5 library was not built with {native}"
+                );
+            }
+        }
+    }
 }
 
 fn main() {

hdf5/Cargo.toml

@@ -15,9 +15,11 @@ edition.workspace = true
 
 [features]
 default = []
-mpio = ["mpi-sys", "hdf5-sys/mpio"]
-lzf = ["lzf-sys", "errno"]
-blosc = ["blosc-sys"]
+mpio = ["dep:mpi-sys", "hdf5-sys/mpio"]
+lzf = ["dep:lzf-sys", "dep:errno"]
+blosc = ["dep:blosc-sys"]
+static = ["hdf5-sys/static"]
+zlib = ["hdf5-sys/zlib"]
 # The features with version numbers such as 1.10.3, 1.12.0 are metafeatures
 # and is only available when the HDF5 library is at least this version.
 # Features have_direct and have_parallel are also metafeatures and dependent