Add [export.body_prepend] to config

docs.md

@@ -488,7 +488,16 @@ renaming_overrides_prefixing = true
 "MyType" = "my_cool_type"
 "my_function" = "BetterFunctionName"
 
-# Table of things to add to the body of any struct, union, or enum that has the
+# Table of things to prepend to the body of any struct, union, or enum that has the
+# given name. This can be used to add things like methods which don't change ABI,
+# mark fields private, etc
+[export.pre_body]
+"MyType" = """
+  MyType() = delete;
+private:
+"""
+
+# Table of things to append to the body of any struct, union, or enum that has the
 # given name. This can be used to add things like methods which don't change ABI.
 [export.body]
 "MyType" = """

src/bindgen/config.rs

@@ -214,6 +214,8 @@ pub struct ExportConfig {
     pub exclude: Vec<String>,
     /// Table of name conversions to apply to item names
     pub rename: HashMap<String, String>,
+    /// Table of raw strings to prepend to the body of items.
+    pub pre_body: HashMap<String, String>,
     /// Table of raw strings to append to the body of items.
     pub body: HashMap<String, String>,
     /// A prefix to add before the name of every item
@@ -229,7 +231,11 @@ impl ExportConfig {
         self.item_types.is_empty() || self.item_types.contains(&item_type)
     }
 
-    pub(crate) fn extra_body(&self, path: &Path) -> Option<&str> {
+    pub(crate) fn pre_body(&self, path: &Path) -> Option<&str> {
+        self.pre_body.get(path.name()).map(|s| s.trim_matches('\n'))
+    }
+
+    pub(crate) fn post_body(&self, path: &Path) -> Option<&str> {
         self.body.get(path.name()).map(|s| s.trim_matches('\n'))
     }
 

src/bindgen/ir/enumeration.rs

@@ -527,6 +527,14 @@ impl Source for Enum {
 
             write!(out, " {}", self.export_name());
             out.open_brace();
+
+            // Emit the pre_body section, if relevant
+            // Only do this here if we're writing C++, since the struct that wraps everything is starting here.
+            // If we're writing C, we aren't wrapping the enum and variant structs definitions, so the actual enum struct willstart down below
+            if let Some(body) = config.export.pre_body(&self.path) {
+                out.write_raw_block(body);
+                out.new_line();
+            }
         }
 
         let enum_name = if let Some(ref tag) = self.tag {
@@ -642,6 +650,14 @@ impl Source for Enum {
                 }
 
                 out.open_brace();
+
+                // Emit the pre_body section, if relevant
+                // Only do this if we're writing C, since the struct is starting right here.
+                // For C++, the struct wraps all of the above variant structs too, and we write the pre_body section at the begining of that
+                if let Some(body) = config.export.pre_body(&self.path) {
+                    out.write_raw_block(body);
+                    out.new_line();
+                }
             }
 
             // C++ allows accessing only common initial sequence of union
@@ -1008,7 +1024,9 @@ impl Source for Enum {
                 }
             }
 
-            if let Some(body) = config.export.extra_body(&self.path) {
+            // Emit the post_body section, if relevant
+            if let Some(body) = config.export.post_body(&self.path) {
+                out.new_line();
                 out.write_raw_block(body);
             }
 

src/bindgen/ir/structure.rs

@@ -452,6 +452,12 @@ impl Source for Struct {
 
         out.open_brace();
 
+        // Emit the pre_body section, if relevant
+        if let Some(body) = config.export.pre_body(&self.path) {
+            out.write_raw_block(body);
+            out.new_line();
+        }
+
         if config.documentation {
             out.write_vertical_source_list(&self.fields, ListType::Cap(";"));
         } else {
@@ -600,7 +606,9 @@ impl Source for Struct {
             }
         }
 
-        if let Some(body) = config.export.extra_body(&self.path) {
+        // Emit the post_body section, if relevant
+        if let Some(body) = config.export.post_body(&self.path) {
+            out.new_line();
             out.write_raw_block(body);
         }
 

src/bindgen/ir/union.rs

@@ -299,6 +299,12 @@ impl Source for Union {
 
         out.open_brace();
 
+        // Emit the pre_body section, if relevant
+        if let Some(body) = config.export.pre_body(&self.path) {
+            out.write_raw_block(body);
+            out.new_line();
+        }
+
         if config.documentation {
             out.write_vertical_source_list(&self.fields, ListType::Cap(";"));
         } else {
@@ -310,7 +316,9 @@ impl Source for Union {
             out.write_vertical_source_list(&vec[..], ListType::Cap(";"));
         }
 
-        if let Some(body) = config.export.extra_body(&self.path) {
+        // Emit the post_body section, if relevant
+        if let Some(body) = config.export.post_body(&self.path) {
+            out.new_line();
             out.write_raw_block(body);
         }
 

src/bindgen/writer.rs

@@ -176,7 +176,6 @@ impl<'a, F: Write> SourceWriter<'a, F> {
     }
 
     pub fn write_raw_block(&mut self, block: &str) {
-        self.new_line();
         self.line_started = true;
         write!(self, "{}", block);
     }

tests/expectations/body.c

@@ -9,6 +9,12 @@ typedef enum {
   Baz1,
 } MyCLikeEnum;
 
+typedef enum {
+  Foo1_Prepended,
+  Bar1_Prepended,
+  Baz1_Prepended,
+} MyCLikeEnum_Prepended;
+
 typedef struct {
   int32_t i;
 #ifdef __cplusplus
@@ -47,4 +53,49 @@ typedef union {
   int32_t extra_member; // yolo
 } MyUnion;
 
-void root(MyFancyStruct s, MyFancyEnum e, MyCLikeEnum c, MyUnion u);
+typedef struct {
+#ifdef __cplusplus
+  inline void prepended_wohoo();
+#endif
+  int32_t i;
+} MyFancyStruct_Prepended;
+
+typedef enum {
+  Foo_Prepended,
+  Bar_Prepended,
+  Baz_Prepended,
+} MyFancyEnum_Prepended_Tag;
+
+typedef struct {
+  int32_t _0;
+} Bar_Prepended_Body;
+
+typedef struct {
+  int32_t _0;
+} Baz_Prepended_Body;
+
+typedef struct {
+  #ifdef __cplusplus
+    inline void wohoo();
+  #endif
+  MyFancyEnum_Prepended_Tag tag;
+  union {
+    Bar_Prepended_Body bar_prepended;
+    Baz_Prepended_Body baz_prepended;
+  };
+} MyFancyEnum_Prepended;
+
+typedef union {
+  int32_t extra_member; // yolo
+  float f;
+  uint32_t u;
+} MyUnion_Prepended;
+
+void root(MyFancyStruct s,
+          MyFancyEnum e,
+          MyCLikeEnum c,
+          MyUnion u,
+          MyFancyStruct_Prepended sp,
+          MyFancyEnum_Prepended ep,
+          MyCLikeEnum_Prepended cp,
+          MyUnion_Prepended up);

tests/expectations/body.compat.c

@@ -9,6 +9,12 @@ typedef enum {
   Baz1,
 } MyCLikeEnum;
 
+typedef enum {
+  Foo1_Prepended,
+  Bar1_Prepended,
+  Baz1_Prepended,
+} MyCLikeEnum_Prepended;
+
 typedef struct {
   int32_t i;
 #ifdef __cplusplus
@@ -47,11 +53,56 @@ typedef union {
   int32_t extra_member; // yolo
 } MyUnion;
 
+typedef struct {
+#ifdef __cplusplus
+  inline void prepended_wohoo();
+#endif
+  int32_t i;
+} MyFancyStruct_Prepended;
+
+typedef enum {
+  Foo_Prepended,
+  Bar_Prepended,
+  Baz_Prepended,
+} MyFancyEnum_Prepended_Tag;
+
+typedef struct {
+  int32_t _0;
+} Bar_Prepended_Body;
+
+typedef struct {
+  int32_t _0;
+} Baz_Prepended_Body;
+
+typedef struct {
+  #ifdef __cplusplus
+    inline void wohoo();
+  #endif
+  MyFancyEnum_Prepended_Tag tag;
+  union {
+    Bar_Prepended_Body bar_prepended;
+    Baz_Prepended_Body baz_prepended;
+  };
+} MyFancyEnum_Prepended;
+
+typedef union {
+  int32_t extra_member; // yolo
+  float f;
+  uint32_t u;
+} MyUnion_Prepended;
+
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
 
-void root(MyFancyStruct s, MyFancyEnum e, MyCLikeEnum c, MyUnion u);
+void root(MyFancyStruct s,
+          MyFancyEnum e,
+          MyCLikeEnum c,
+          MyUnion u,
+          MyFancyStruct_Prepended sp,
+          MyFancyEnum_Prepended ep,
+          MyCLikeEnum_Prepended cp,
+          MyUnion_Prepended up);
 
 #ifdef __cplusplus
 } // extern "C"

tests/expectations/body.cpp

@@ -9,6 +9,12 @@ enum class MyCLikeEnum {
   Baz1,
 };
 
+enum class MyCLikeEnum_Prepended {
+  Foo1_Prepended,
+  Bar1_Prepended,
+  Baz1_Prepended,
+};
+
 struct MyFancyStruct {
   int32_t i;
 #ifdef __cplusplus
@@ -47,8 +53,53 @@ union MyUnion {
   int32_t extra_member; // yolo
 };
 
+struct MyFancyStruct_Prepended {
+#ifdef __cplusplus
+  inline void prepended_wohoo();
+#endif
+  int32_t i;
+};
+
+struct MyFancyEnum_Prepended {
+  #ifdef __cplusplus
+    inline void wohoo();
+  #endif
+  enum class Tag {
+    Foo_Prepended,
+    Bar_Prepended,
+    Baz_Prepended,
+  };
+
+  struct Bar_Prepended_Body {
+    int32_t _0;
+  };
+
+  struct Baz_Prepended_Body {
+    int32_t _0;
+  };
+
+  Tag tag;
+  union {
+    Bar_Prepended_Body bar_prepended;
+    Baz_Prepended_Body baz_prepended;
+  };
+};
+
+union MyUnion_Prepended {
+  int32_t extra_member; // yolo
+  float f;
+  uint32_t u;
+};
+
 extern "C" {
 
-void root(MyFancyStruct s, MyFancyEnum e, MyCLikeEnum c, MyUnion u);
+void root(MyFancyStruct s,
+          MyFancyEnum e,
+          MyCLikeEnum c,
+          MyUnion u,
+          MyFancyStruct_Prepended sp,
+          MyFancyEnum_Prepended ep,
+          MyCLikeEnum_Prepended cp,
+          MyUnion_Prepended up);
 
 } // extern "C"