Merge pull request #13 from jelmer/asrawfd

Implement AsRawFd for PyFileLikeObject
omerbenamram · Nov 27, 2023 · d2085e4 · d2085e4
2 parents 14e8f5f + 2abeb12
commit d2085e4
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Showing 3 changed files with 29 additions and 4 deletions.
diff --git a/README.md b/README.md
@@ -52,7 +52,7 @@ impl FileOrFileLike {
             }
 
             // is a file-like
-            match PyFileLikeObject::with_requirements(path_or_file_like, true, false, true) {
+            match PyFileLikeObject::with_requirements(path_or_file_like, true, false, true, false) {
                 Ok(f) => Ok(FileOrFileLike::FileLike(f)),
                 Err(e) => Err(e)
             }

diff --git a/examples/path_or_file_like/src/lib.rs b/examples/path_or_file_like/src/lib.rs
@@ -24,7 +24,7 @@ impl FileOrFileLike {
             }
 
             // is a file-like
-            match PyFileLikeObject::with_requirements(path_or_file_like, true, false, true) {
+            match PyFileLikeObject::with_requirements(path_or_file_like, true, false, true, false) {
                 Ok(f) => Ok(FileOrFileLike::FileLike(f)),
                 Err(e) => Err(e),
             }
@@ -61,7 +61,7 @@ fn accepts_path_or_file_like_read(path_or_file_like: PyObject) -> PyResult<Strin
 /// Opens a file or file-like, and write a string to it.
 fn accepts_file_like_write(file_like: PyObject) -> PyResult<()> {
     // is a file-like
-    match PyFileLikeObject::with_requirements(file_like, false, true, false) {
+    match PyFileLikeObject::with_requirements(file_like, false, true, false, false) {
         Ok(mut f) => {
             println!("Its a file-like object");
             f.write_all(b"Hello, world!")?;

diff --git a/src/lib.rs b/src/lib.rs
@@ -4,6 +4,7 @@ use pyo3::types::{PyBytes, PyString, PyType};
 
 use std::io;
 use std::io::{Read, Seek, SeekFrom, Write};
+use std::os::fd::{AsRawFd, RawFd};
 
 #[derive(Debug)]
 pub struct PyFileLikeObject {
@@ -33,12 +34,13 @@ impl PyFileLikeObject {
 
     /// Same as `PyFileLikeObject::new`, but validates that the underlying
     /// python object has a `read`, `write`, and `seek` methods in respect to parameters.
-    /// Will return a `TypeError` if object does not have `read`, `seek`, and `write` methods.
+    /// Will return a `TypeError` if object does not have `read`, `seek`, `write` and `fileno` methods.
     pub fn with_requirements(
         object: PyObject,
         read: bool,
         write: bool,
         seek: bool,
+        fileno: bool,
     ) -> PyResult<Self> {
         Python::with_gil(|py| {
             if read && object.getattr(py, "read").is_err() {
@@ -59,6 +61,12 @@ impl PyFileLikeObject {
                 ));
             }
 
+            if fileno && object.getattr(py, "fileno").is_err() {
+                return Err(PyErr::new::<PyTypeError, _>(
+                    "Object does not have a .fileno() method.",
+                ));
+            }
+
             PyFileLikeObject::new(object)
         })
     }
@@ -179,3 +187,20 @@ impl Seek for PyFileLikeObject {
         })
     }
 }
+
+impl AsRawFd for PyFileLikeObject {
+    fn as_raw_fd(&self) -> RawFd {
+        Python::with_gil(|py| {
+            let fileno = self
+                .inner
+                .getattr(py, "fileno")
+                .expect("Object does not have a fileno() method.");
+
+            let fd = fileno
+                .call(py, (), None)
+                .expect("fileno() method did not return a file descriptor.");
+
+            fd.extract(py).expect("File descriptor is not an integer.")
+        })
+    }
+}