eliminate dep on rental

Trading a lot of gross for a single line of gross

Cargo.toml

@@ -32,7 +32,6 @@ leb128 = "0.2"
 libc = "0.2"
 log = "0.4"
 open = "1.2"
-rental = "0.5"
 native-tls = "0.2"
 # file change notification
 notify = "4.0"

src/font/parser.rs

@@ -5,6 +5,7 @@
 use crate::config::Config;
 use crate::config::FontAttributes;
 use crate::font::locator::FontDataHandle;
+use allsorts::binary::read::{ReadScope, ReadScopeOwned};
 use allsorts::fontfile::FontFile;
 use allsorts::tables::{
     FontTableProvider, HeadTable, MaxpTable, NameTable, OffsetTable, OpenTypeFont, TTCHeader,
@@ -16,8 +17,11 @@ use std::path::{Path, PathBuf};
 /// Represents a parsed font
 pub struct ParsedFont {
     index: usize,
-    file: gah::OwnedFontFile,
+    file: FontFile<'static>,
     names: Names,
+
+    // Must be last: this keeps the 'static items alive
+    _scope: ReadScopeOwned,
 }
 
 #[derive(Debug)]
@@ -97,15 +101,20 @@ impl ParsedFont {
 
         let index = index as usize;
 
-        let file = parse(data)?;
+        let owned_scope = ReadScopeOwned::new(ReadScope::new(&data));
 
-        let names = file.rent(|file| -> Fallible<Names> {
-            let name_table = name_table_data(file, index)?;
-            let names = Names::from_name_table_data(name_table)?;
-            Ok(names)
-        })?;
+        let file: FontFile<'static> =
+            unsafe { std::mem::transmute(owned_scope.scope().read::<FontFile>()?) };
 
-        Ok(Self { index, file, names })
+        let name_table = name_table_data(&file, index)?;
+        let names = Names::from_name_table_data(name_table)?;
+
+        Ok(Self {
+            index,
+            file,
+            names,
+            _scope: owned_scope,
+        })
     }
 
     pub fn names(&self) -> &Names {
@@ -113,30 +122,6 @@ impl ParsedFont {
     }
 }
 
-rental! {
-    /// This is horrible, but I don't see an obvious way to
-    /// end up with an owned FontFile instance from the standard
-    /// set of functions exported by allsorts
-    mod gah {
-        use super::*;
-        #[rental]
-        pub struct OwnedFontFile {
-            head: Vec<u8>,
-            file: FontFile<'head>,
-        }
-    }
-}
-
-/// Parse bytes into an OwnedFontFile
-fn parse(data: Vec<u8>) -> Fallible<gah::OwnedFontFile> {
-    gah::OwnedFontFile::try_new(data, |data| {
-        let scope = allsorts::binary::read::ReadScope::new(&data);
-        let file = scope.read::<FontFile>()?;
-        Ok(file)
-    })
-    .map_err(|e| e.0)
-}
-
 fn collect_font_info(
     name_table_data: &[u8],
     path: &Path,

src/main.rs

@@ -1,9 +1,6 @@
 // Don't create a new standard console window when launched from the windows GUI.
 #![windows_subsystem = "windows"]
 
-#[macro_use]
-extern crate rental;
-
 use failure::{err_msg, format_err, Error, Fallible};
 use promise::Future;
 use std::ffi::OsString;