From 81f79e84e78345fa8911382860921cf7865dce72 Mon Sep 17 00:00:00 2001
From: NikVolf <nikvolf@gmail.com>
Date: Tue, 9 May 2017 17:34:36 +0300
Subject: [PATCH] global builder

---
 src/builder/code.rs          |  1 -
 src/builder/global.rs        | 83 ++++++++++++++++++++++++++++++++++++
 src/builder/mod.rs           |  4 +-
 src/elements/global_entry.rs |  7 +++
 4 files changed, 93 insertions(+), 2 deletions(-)
 create mode 100644 src/builder/global.rs

diff --git a/src/builder/code.rs b/src/builder/code.rs
index 710a377..a863938 100644
--- a/src/builder/code.rs
+++ b/src/builder/code.rs
@@ -202,7 +202,6 @@ impl<F> FuncBodyBuilder<F> {
 }
 
 impl<F> FuncBodyBuilder<F> where F: Invoke<elements::FuncBody> {
-
     pub fn with_func(mut self, func: elements::FuncBody) -> Self {
         self.body = func;
         self
diff --git a/src/builder/global.rs b/src/builder/global.rs
new file mode 100644
index 0000000..2cae4ba
--- /dev/null
+++ b/src/builder/global.rs
@@ -0,0 +1,83 @@
+use super::invoke::{Invoke, Identity};
+use super::misc::ValueTypeBuilder;
+use elements;
+
+pub struct GlobalBuilder<F=Identity> {
+    callback: F,
+    value_type: elements::ValueType,
+    is_mutable: bool,
+    init_expr: elements::InitExpr,
+}
+
+impl GlobalBuilder {
+    pub fn new() -> Self {
+        GlobalBuilder::with_callback(Identity)
+    }
+}
+
+impl<F> GlobalBuilder<F> {
+    pub fn with_callback(callback: F) -> Self {
+        GlobalBuilder {
+            callback: callback,
+            value_type: elements::ValueType::I32,
+            init_expr: elements::InitExpr::empty(),
+            is_mutable: false,
+        }
+    }
+
+    pub fn with_type(mut self, value_type: elements::ValueType) -> Self {
+        self.value_type = value_type;
+        self
+    }
+
+    pub fn mutable(mut self) -> Self {
+        self.is_mutable = true;
+        self
+    }
+
+    pub fn init_expr(mut self, opcode: elements::Opcode) -> Self {
+        self.init_expr = elements::InitExpr::new(vec![opcode, elements::Opcode::End]);
+        self
+    }
+
+    pub fn value_type(self) -> ValueTypeBuilder<Self> {
+        ValueTypeBuilder::with_callback(self)
+    }
+}
+
+impl<F> GlobalBuilder<F> where F: Invoke<elements::GlobalEntry> {
+    pub fn build(self) -> F::Result {
+        self.callback.invoke(
+            elements::GlobalEntry::new(
+                elements::GlobalType::new(self.value_type, self.is_mutable), 
+                self.init_expr,
+            )
+        )
+    }
+}
+
+
+impl<F> Invoke<elements::ValueType> for GlobalBuilder<F> {
+    type Result = Self;
+    fn invoke(self, the_type: elements::ValueType) -> Self {
+        self.with_type(the_type)
+    }
+}
+
+/// New builder for export entry
+pub fn global() -> GlobalBuilder {
+    GlobalBuilder::new()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::global;
+    use elements;
+
+    #[test]
+    fn example() {
+        let entry = global().value_type().i32().build();
+        assert_eq!(entry.global_type().content_type(), elements::ValueType::I32);
+        assert_eq!(entry.global_type().is_mutable(), false);
+    }
+}
\ No newline at end of file
diff --git a/src/builder/mod.rs b/src/builder/mod.rs
index f77ed5c..8ecea0e 100644
--- a/src/builder/mod.rs
+++ b/src/builder/mod.rs
@@ -6,8 +6,10 @@ mod code;
 mod misc;
 mod import;
 mod export;
+mod global;
 
 pub use self::module::{module, from_module, ModuleBuilder};
 pub use self::code::{signatures, signature, function};
 pub use self::import::import;
-pub use self::export::export;
\ No newline at end of file
+pub use self::export::export;
+pub use self::global::global;
\ No newline at end of file
diff --git a/src/elements/global_entry.rs b/src/elements/global_entry.rs
index 9a79f4d..1f27b21 100644
--- a/src/elements/global_entry.rs
+++ b/src/elements/global_entry.rs
@@ -8,6 +8,13 @@ pub struct GlobalEntry {
 }
 
 impl GlobalEntry {
+    /// New global entry
+    pub fn new(global_type: GlobalType, init_expr: InitExpr) -> Self {
+        GlobalEntry {
+            global_type: global_type,
+            init_expr: init_expr,
+        }
+    }
     /// Global type.
     pub fn global_type(&self) -> &GlobalType { &self.global_type }
     /// Initialization expression (opcodes) for global.