Use `quote` instead of `syntex` for Rust code generation

The `syntex` crate is unmaintained. It is slow to build, and additionally it
requires that we pre-process `src/codegen/mod.rs` before we build the `bindgen`
crate.

The `quote` crate provides similar quasi-quoting functionality, is maintained,
and builds faster. It doesn't have a typed API or builders, however; it only
deals with tokens.

Before this commit:

```
$ cargo clean; cargo build
<snip>
    Finished dev [unoptimized + debuginfo] target(s) in 98.75 secs
```

After this commit:

```
$ cargo clean; cargo build
<snip>
    Finished dev [unoptimized + debuginfo] target(s) in 46.26 secs
```

Build time is cut in half! But what about run time?

Before this commit:

```
Generated Stylo bindings in: Duration { secs: 3, nanos: 521105668 }
```

After this commit:

```
Generated Stylo bindings in: Duration { secs: 3, nanos: 548797242 }
```

So it appears to be about 20ms slower at generating Stylo bindings, but I
suspect this is well within the noise.

Finally, this also lets us remove that nasty `mem::transmute` inside
`bindgen::ir::BindgenContext::gen` that was used for the old `syntex`
context. Now `BindgenContext` doesn't have a lifetime parameter either. This
should make it easier to revisit doing our analyses in parallel with `rayon`,
since that context was one of the things that made it hard for `BindgenContext`
to implement `Sync`.

Fixes #925

1 files changed, 48 insertions, 0 deletions

diff --git a/tests/headers/nsBaseHashtable.hpp b/tests/headers/nsBaseHashtable.hpp
new file mode 100644
index 00000000..36a480f2
--- /dev/null
+++ b/tests/headers/nsBaseHashtable.hpp
@@ -0,0 +1,48 @@
+// bindgen-flags: -- -std=c++14
+
+using uint32_t = unsigned long;
+using size_t = unsigned long long;
+
+template<class KeyClass, class DataType>
+class nsBaseHashtableET {
+};
+
+template<class Entry>
+class nsTHashtable {
+};
+
+template<class KeyClass, class DataType, class UserDataType>
+class nsBaseHashtable
+  : protected nsTHashtable<nsBaseHashtableET<KeyClass, DataType>>
+{
+
+public:
+  typedef typename KeyClass::KeyType KeyType;
+  typedef nsBaseHashtableET<KeyClass, DataType> EntryType;
+
+  using nsTHashtable<EntryType>::Contains;
+  using nsTHashtable<EntryType>::GetGeneration;
+
+  nsBaseHashtable() {}
+  explicit nsBaseHashtable(uint32_t);
+
+  struct LookupResult {
+  private:
+    EntryType* mEntry;
+    nsBaseHashtable& mTable;
+
+  public:
+    LookupResult(EntryType*, nsBaseHashtable&);
+  };
+
+  struct EntryPtr {
+  private:
+    EntryType& mEntry;
+    bool mExistingEntry;
+
+  public:
+    EntryPtr(nsBaseHashtable&, EntryType*, bool);
+    ~EntryPtr();
+  };
+
+};