Don't derive Copy in FFI structs/unions that contain pointers

Clone is still derived to as explicitly cloning the structs is less of a
problem, but implicitly copying them can easily cause double frees.

Fixes #1048

Author: sdroege

src/analysis/types.rs

@@ -233,10 +233,137 @@ pub trait DerivesCopy {
     fn derives_copy(&self, lib: &Library) -> bool;
 }
 
-impl<T: IsIncomplete> DerivesCopy for T {
+impl DerivesCopy for Fundamental {
     fn derives_copy(&self, lib: &Library) -> bool {
-        // Copy is derived for all complete types.
-        !self.is_incomplete(lib)
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        // None of the pointer types
+        !matches!(
+            self,
+            Fundamental::Pointer
+                | Fundamental::VarArgs
+                | Fundamental::Utf8
+                | Fundamental::Filename
+                | Fundamental::IntPtr
+                | Fundamental::UIntPtr
+                | Fundamental::OsString
+                | Fundamental::Unsupported
+        )
+    }
+}
+
+impl DerivesCopy for Alias {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        !self.is_ptr()
+    }
+}
+
+impl DerivesCopy for Field {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        !self.is_ptr()
+    }
+}
+
+impl<'a> DerivesCopy for &'a [Field] {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        for field in self.iter() {
+            if field.is_ptr() {
+                return false;
+            }
+        }
+
+        true
+    }
+}
+
+impl DerivesCopy for Class {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        self.fields.as_slice().derives_copy(lib)
+    }
+}
+
+impl DerivesCopy for Record {
+    #[allow(clippy::if_same_then_else)]
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        self.fields.as_slice().derives_copy(lib)
+    }
+}
+
+impl DerivesCopy for Union {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        self.fields.as_slice().derives_copy(lib)
+    }
+}
+
+impl DerivesCopy for Function {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        true
+    }
+}
+
+impl DerivesCopy for TypeId {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        lib.type_(*self).derives_copy(lib)
+    }
+}
+
+impl DerivesCopy for Type {
+    fn derives_copy(&self, lib: &Library) -> bool {
+        if self.is_incomplete(lib) {
+            return false;
+        }
+
+        match *self {
+            Type::Fundamental(ref fundamental) => fundamental.derives_copy(lib),
+            Type::Alias(ref alias) => alias.derives_copy(lib),
+            Type::FixedArray(tid, ..) => tid.derives_copy(lib),
+            Type::Class(ref klass) => klass.derives_copy(lib),
+            Type::Record(ref record) => record.derives_copy(lib),
+            Type::Union(ref union) => union.derives_copy(lib),
+            Type::Function(ref function) => function.derives_copy(lib),
+            Type::Enumeration(..) | Type::Bitfield(..) | Type::Interface(..) => true,
+            Type::Custom(..)
+            | Type::Array(..)
+            | Type::CArray(..)
+            | Type::PtrArray(..)
+            | Type::HashTable(..)
+            | Type::List(..)
+            | Type::SList(..) => false,
+        }
     }
 }
 

src/codegen/sys/fields.rs

@@ -13,6 +13,7 @@ pub struct Fields {
     pub external: bool,
     /// Reason for truncating the representation, if any.
     pub truncated: Option<String>,
+    derives_clone: bool,
     derives_copy: bool,
     /// "struct" or "union"
     pub kind: &'static str,
@@ -38,6 +39,8 @@ impl Fields {
         let mut traits = Vec::new();
         if self.derives_copy {
             traits.push("Copy");
+        }
+        if self.derives_clone {
             traits.push("Clone");
         }
         traits
@@ -58,11 +61,13 @@ impl FieldInfo {
 pub fn from_record(env: &Env, record: &Record) -> Fields {
     let (fields, truncated) = analyze_fields(env, false, &record.fields);
     let derives_copy = truncated.is_none() && record.derives_copy(&env.library);
+    let derives_clone = truncated.is_none() && !record.is_incomplete(&env.library);
     Fields {
         name: record.c_type.clone(),
         external: record.is_external(&env.library),
         truncated,
         derives_copy,
+        derives_clone,
         kind: "struct",
         cfg_condition: get_gobject_cfg_condition(env, &record.name),
         fields,
@@ -72,11 +77,13 @@ pub fn from_record(env: &Env, record: &Record) -> Fields {
 pub fn from_class(env: &Env, klass: &Class) -> Fields {
     let (fields, truncated) = analyze_fields(env, false, &klass.fields);
     let derives_copy = truncated.is_none() && klass.derives_copy(&env.library);
+    let derives_clone = truncated.is_none() && !klass.is_incomplete(&env.library);
     Fields {
         name: klass.c_type.clone(),
         external: klass.is_external(&env.library),
         truncated,
         derives_copy,
+        derives_clone,
         kind: "struct",
         cfg_condition: get_gobject_cfg_condition(env, &klass.name),
         fields,
@@ -86,11 +93,13 @@ pub fn from_class(env: &Env, klass: &Class) -> Fields {
 pub fn from_union(env: &Env, union: &Union) -> Fields {
     let (fields, truncated) = analyze_fields(env, true, &union.fields);
     let derives_copy = truncated.is_none() && union.derives_copy(&env.library);
+    let derives_clone = truncated.is_none() && !union.is_incomplete(&env.library);
     Fields {
         name: union.c_type.as_ref().unwrap().clone(),
         external: union.is_external(&env.library),
         truncated,
         derives_copy,
+        derives_clone,
         kind: "union",
         cfg_condition: None,
         fields,