Fix incomplete attached file problem

crates/bridge_core/src/lib.rs

@@ -674,6 +674,11 @@
         rhandle.read_exact(buf).map_err(Error::from)
     }
 
+    fn input_read_partial(&mut self, handle: *mut InputHandle, buf: &mut [u8]) -> Result<usize> {
+        let rhandle: &mut InputHandle = unsafe { &mut *handle };
+        rhandle.read(buf).map_err(Error::from)
+    }
+
     fn input_getc(&mut self, handle: *mut InputHandle) -> Result<u8> {
         let rhandle: &mut InputHandle = unsafe { &mut *handle };
         rhandle.getc()
@@ -1181,6 +1186,9 @@
 
 /// Read data from a Tectonic input handle
 ///
+/// This read corresponds to Rust's read_exact, i.e. it will return exactly the number of requested
+/// bytes or error (-1).
+///
 /// # Safety
 ///
 /// This function is unsafe because it dereferences raw C pointers.
@@ -1202,6 +1210,32 @@
     }
 }
 
+/// Read data from a Tectonic input handle
+///
+/// This read corresponds to Rust's read, i.e. it can return less bytes than requested (and does
+/// when buffering)
+///
+/// # Safety
+///
+/// This function is unsafe because it dereferences raw C pointers.
+#[no_mangle]
+pub unsafe extern "C" fn ttbc_input_read_partial(
+    es: &mut CoreBridgeState,
+    handle: *mut InputHandle,
+    data: *mut u8,
+    len: libc::size_t,
+) -> libc::ssize_t {
+    let rdata = slice::from_raw_parts_mut(data, len);
+
+    match es.input_read_partial(handle, rdata) {
+        Ok(size) => size as isize,
+        Err(e) => {
+            tt_warning!(es.status, "{}-byte read failed", len; e);
+            -1
+        }
+    }
+}
+
 /// Close a Tectonic input file.
 #[no_mangle]
 pub extern "C" fn ttbc_input_close(

crates/bridge_core/support/support.c

@@ -285,6 +285,11 @@
     return ttbc_input_read(tectonic_global_bridge_core, handle, (uint8_t *) data, len);
 }
 
+ssize_t
+ttstub_input_read_partial(rust_input_handle_t handle, char *data, size_t len)
+{
+    return ttbc_input_read_partial(tectonic_global_bridge_core, handle, (uint8_t *) data, len);
+}
 
 int
 ttstub_input_getc(rust_input_handle_t handle)

crates/bridge_core/support/tectonic_bridge_core.h

@@ -243,6 +243,7 @@ size_t ttstub_input_get_size(rust_input_handle_t handle);
 time_t ttstub_input_get_mtime(rust_input_handle_t handle);
 size_t ttstub_input_seek(rust_input_handle_t handle, ssize_t offset, int whence);
 ssize_t ttstub_input_read(rust_input_handle_t handle, char *data, size_t len);
+ssize_t ttstub_input_read_partial(rust_input_handle_t handle, char *data, size_t len);
 int ttstub_input_getc(rust_input_handle_t handle);
 int ttstub_input_ungetc(rust_input_handle_t handle, int ch);
 int ttstub_input_close(rust_input_handle_t handle);

crates/bridge_core/support/tectonic_bridge_core_generated.h

@@ -296,6 +296,8 @@ int ttbc_input_ungetc(ttbc_state_t *es, ttbc_input_handle_t *handle, int ch);
  */
 ssize_t ttbc_input_read(ttbc_state_t *es, ttbc_input_handle_t *handle, uint8_t *data, size_t len);
 
+ssize_t ttbc_input_read_partial(ttbc_state_t *es, ttbc_input_handle_t *handle, uint8_t *data, size_t len);
+
 /**
  * Close a Tectonic input file.
  */

crates/pdf_io/pdf_io/dpx-spc_pdfm.c

@@ -1664,7 +1664,7 @@
     }
     fstream = pdf_new_stream(STREAM_COMPRESS);
     while ((nb_read =
-            ttstub_input_read(handle, work_buffer, WORK_BUFFER_SIZE)) > 0)
+            ttstub_input_read_partial(handle, work_buffer, WORK_BUFFER_SIZE)) > 0)
       pdf_add_stream(fstream, work_buffer, nb_read);
     ttstub_input_close(handle);
     break;