From 81ede5d6be4f195865b8d39e51631a812a2c6c4b Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Mon, 22 May 2017 20:55:51 +1000
Subject: [PATCH 01/10] Fixed bad struct JNA mapping and some memory leaks

Incorporated changes from #4. Also looked into the way that we free
memory, to fix some memory leaks.
---
 README.md                                     | 12 +--
 generate-link-table                           | 89 +++++++++++++++++++
 .../com/github/drrb/javarust/Greeting.java    | 13 ++-
 .../com/github/drrb/javarust/GreetingSet.java | 12 ++-
 .../com/github/drrb/javarust/Greetings.java   |  4 +-
 .../com/github/drrb/javarust/lib/greetings.rs | 62 ++++++-------
 .../github/drrb/javarust/GreetingsTest.java   | 49 +++++-----
 7 files changed, 170 insertions(+), 71 deletions(-)
 create mode 100755 generate-link-table

diff --git a/README.md b/README.md
index 25d5a1a..876a686 100644
--- a/README.md
+++ b/README.md
@@ -29,12 +29,12 @@ and the [Rust code](src/main/rust/com/github/drrb/javarust/lib/greetings.rs). Th
 implementation is heavily commented to explain it.
 
 So far, it contains examples of the following (click the links to see!):
-- *[Arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L42)*: passing simple arguments from Java to Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L44) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L73))
-- *[Return values](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L47)*: returning simple values from Rust to Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L49) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L86))
-- *[Struct arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L54)*: passing structs to Rust from Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L54) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L97))
-- *[Returning structs (2 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L63)*: returning structs from Rust by value and by reference ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L62) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L105))
-- *[Callbacks (3 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L80)*: passing callbacks to Rust that get called from the Rust code ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L84) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L122))
-- *[Freeing memory](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L76)*: freeing memory allocated in Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L144) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L175))
+- *[Arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L46)*: passing simple arguments from Java to Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L45) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L82))
+- *[Return values](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L51)*: returning simple values from Rust to Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L50) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L92))
+- *[Struct arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L57)*: passing structs to Rust from Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L55) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L101))
+- *[Returning structs (2 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L66)*: returning structs from Rust by value and by reference ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L72) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L110))
+- *[Callbacks (3 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L81)*: passing callbacks to Rust that get called from the Rust code ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L85) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L130))
+- *[Freeing memory](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L68)*: freeing memory allocated in Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L115) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L172))
 
 ## Building and Running the Tests
 
diff --git a/generate-link-table b/generate-link-table
new file mode 100755
index 0000000..c6e55c3
--- /dev/null
+++ b/generate-link-table
@@ -0,0 +1,89 @@
+#!/usr/bin/env ruby
+
+require "ostruct"
+
+class Concept < OpenStruct
+  def to_markdown
+    "*#{test_link}*: #{description} (#{java_link} / #{rust_link})"
+  end
+
+  def test_link
+    link text: name, regex: test_regex, file: "src/test/java/com/github/drrb/javarust/GreetingsTest.java"
+  end
+
+  def java_link
+    link text: "Java side", regex: java_regex, file: "src/main/java/com/github/drrb/javarust/Greetings.java"
+  end
+
+  def rust_link
+    link text: "Rust side", regex: rust_regex, file: "src/main/rust/com/github/drrb/javarust/lib/greetings.rs"
+  end
+
+  private
+  def link(text:, regex:, file:)
+    line = find_line(regex, file)
+    "[#{text}](#{file}#L#{line + 1})"
+  end
+
+  def find_line(regex, file)
+    lines = File.read(file).lines.each_with_index
+    line, index = lines.find {|line, index| line =~ regex}
+    unless line
+      raise "Couldn't find #{regex.inspect} in #{file.inspect}"
+    end
+    index + 1
+  end
+end
+
+class Array
+  def to_markdown_points
+    map {|e| "- #{e}" }.join("\n")
+  end
+end
+
+concepts = [
+  Concept.new(
+    name: "Arguments",
+    description: "passing simple arguments from Java to Rust",
+    test_regex: /shouldAcceptStringParameterFromJavaToRust/,
+    java_regex: /void printGreeting/,
+    rust_regex: /pub extern fn printGreeting/
+  ),
+  Concept.new(
+    name: "Return values",
+    description: "returning simple values from Rust to Java",
+    test_regex: /public void shouldAcceptStringFromJavaToRustAndReturnAnotherOne/,
+    java_regex: /String renderGreeting\(String name\)/,
+    rust_regex: /pub extern fn renderGreeting/
+  ),
+  Concept.new(
+    name: "Struct arguments",
+    description: "passing structs to Rust from Java",
+    test_regex: /public void shouldAcceptAStructFromJavaToRust/,
+    java_regex: /String greet\(Person john\)/,
+    rust_regex: /pub extern fn greet\(person: &Person\)/
+  ),
+  Concept.new(
+    name: "Returning structs (2 examples)",
+    description: "returning structs from Rust by value and by reference",
+    test_regex: /public void shouldGetAStructFromRustByValue/,
+    java_regex: /Greeting.ByValue getGreetingByValue/,
+    rust_regex: /pub extern fn getGreetingByValue/
+  ),
+  Concept.new(
+    name: "Callbacks (3 examples)",
+    description: "passing callbacks to Rust that get called from the Rust code",
+    test_regex: /public void shouldGetAStringFromRustInACallback/,
+    java_regex: /void callMeBack\(GreetingCallback callback\)/,
+    rust_regex: /pub extern fn callMeBack/
+  ),
+  Concept.new(
+    name: "Freeing memory",
+    description: "freeing memory allocated in Rust",
+    test_regex: /try \(Greeting greeting/,
+    java_regex: /void dropGreeting\(Greeting greeting\)/,
+    rust_regex: /pub extern fn dropGreeting/
+  )
+]
+
+puts concepts.map(&:to_markdown).to_markdown_points
diff --git a/src/main/java/com/github/drrb/javarust/Greeting.java b/src/main/java/com/github/drrb/javarust/Greeting.java
index c860dd1..aa3ec61 100644
--- a/src/main/java/com/github/drrb/javarust/Greeting.java
+++ b/src/main/java/com/github/drrb/javarust/Greeting.java
@@ -17,15 +17,18 @@
 package com.github.drrb.javarust;
 
 import com.sun.jna.Structure;
-import static java.util.Arrays.asList;
+
+import java.io.Closeable;
 import java.util.List;
 
+import static java.util.Arrays.asList;
+
 /**
  * A struct that we return from Rust to Java.
  * 
  * This is the Java representation of the Greeting struct in Rust.
  */
-public class Greeting extends Structure {
+public class Greeting extends Structure implements Closeable {
 
     public static class ByReference extends Greeting implements Structure.ByReference {
     }
@@ -43,4 +46,10 @@ public String getText() {
     protected List<String> getFieldOrder() {
         return asList("text");
     }
+
+    @Override
+    public void close() {
+        // Send the struct back to rust for the memory to be freed
+        Greetings.INSTANCE.dropGreeting(this);
+    }
 }
diff --git a/src/main/java/com/github/drrb/javarust/GreetingSet.java b/src/main/java/com/github/drrb/javarust/GreetingSet.java
index a8cfda6..06ed511 100644
--- a/src/main/java/com/github/drrb/javarust/GreetingSet.java
+++ b/src/main/java/com/github/drrb/javarust/GreetingSet.java
@@ -17,6 +17,8 @@
 package com.github.drrb.javarust;
 
 import com.sun.jna.Structure;
+
+import java.io.Closeable;
 import java.util.Arrays;
 import java.util.List;
 
@@ -29,7 +31,13 @@ public class GreetingSet extends Structure {
     public static class ByReference extends GreetingSet implements Structure.ByReference {
     }
 
-    public static class ByValue extends GreetingSet implements Structure.ByValue {
+    public static class ByValue extends GreetingSet implements Structure.ByValue, Closeable {
+
+        @Override
+        public void close() {
+            Greetings.INSTANCE.dropGreetingSet(this);
+        }
+
     }
 
     /**
@@ -38,7 +46,7 @@ public static class ByValue extends GreetingSet implements Structure.ByValue {
      * Actually, this is a pointer to a bunch of struct instances that are next
      * to each other in memory. We cast it to an array in {@link #getGreetings()}.
      * 
-     * NB: We need to explicity specify that the field is a pointer (i.e. we need
+     * NB: We need to explicitly specify that the field is a pointer (i.e. we need
      * to use ByReference) because, by default, JNA assumes that struct fields 
      * are not pointers (i.e. the if you just say "Greeting", JNA assumes 
      * "Greeting.ByValue" here).
diff --git a/src/main/java/com/github/drrb/javarust/Greetings.java b/src/main/java/com/github/drrb/javarust/Greetings.java
index c395be5..aa65fc6 100644
--- a/src/main/java/com/github/drrb/javarust/Greetings.java
+++ b/src/main/java/com/github/drrb/javarust/Greetings.java
@@ -76,7 +76,7 @@ public interface Greetings extends Library {
      * This is the same as returning a {@link GreetingSet.ByReference}. JNA assumes
      * it's by reference when it's returned from a native function.
      */
-    GreetingSet renderGreetings();
+    GreetingSet.ByValue renderGreetings();
 
     /**
      * Passing a callback that will be called from Rust with individual strings
@@ -116,5 +116,5 @@ interface GreetingSetCallback extends Callback {
     /**
      * Free the memory used by a GreetingSet
      */
-    void dropGreetingSet(GreetingSet greetingSet);
+    void dropGreetingSet(GreetingSet.ByValue greetingSet);
 }
diff --git a/src/main/rust/com/github/drrb/javarust/lib/greetings.rs b/src/main/rust/com/github/drrb/javarust/lib/greetings.rs
index 568dae6..ec00661 100644
--- a/src/main/rust/com/github/drrb/javarust/lib/greetings.rs
+++ b/src/main/rust/com/github/drrb/javarust/lib/greetings.rs
@@ -21,28 +21,23 @@
 use std::ffi::{CStr,CString};
 use std::str;
 use std::mem;
-
-// Normally we'd get these from libc, but that's unstable in 1.0 Beta
-mod mylibc {
-    #[allow(non_camel_case_types)]
-    pub type c_int = i32;
-    #[allow(non_camel_case_types)]
-    pub type c_char = i8;
-}
-use mylibc::c_int;
-use mylibc::c_char;
+use std::os::raw::c_char;
 
 // GreetingSet corresponds to com.github.drrb.javarust.GreetingSet in Java. It is marked with
 // repr(c), as are all the structs passed back to Java. This makes sure the structs are represented
 // in memory in a way JNA can read them.
 #[repr(C)]
 pub struct GreetingSet {
-    // A pointer to an array of Greetings. This is converted to a Greeting.ByReference by JNA.
-    greetings: Box<[Greeting]>,
-    // The size of the array. We need to pass it back to Java so that we know how long the array
-    // is (JNA can't guess the size). We need to do this with all arrays created in Java and read
-    // in Rust (or vise-versa). This c_int is converted to a Java int by JNA.
-    number_of_greetings: c_int
+    // A struct that includes a pointer to an array of Greetings and a size. JNA will convert this
+    // to two fields: a Greeting.ByReference and an int.
+    greetings: Box<[Greeting]>
+}
+
+impl Drop for GreetingSet {
+    fn drop(&mut self) {
+        // Print a message when we drop the object, so that we know we're not leaking memory
+        println!("Dropping GreetingSet");
+    }
 }
 
 // Greeting corresponds to com.github.drrb.javarust.Greeting in Java. It is marked with
@@ -63,6 +58,12 @@ impl Greeting {
     }
 }
 
+impl Drop for Greeting {
+    fn drop(&mut self) {
+        println!("Dropping Greeting: {}", to_string(self.text));
+    }
+}
+
 #[repr(C)]
 #[allow(missing_copy_implementations)]
 pub struct Person {
@@ -144,30 +145,25 @@ pub extern fn callMeBack(callback: extern "stdcall" fn(*const c_char)) {
 /// In this example we send a pointer to a struct back to Java via the callback.
 #[no_mangle]
 #[allow(non_snake_case)]
-pub extern fn sendGreetings(callback: extern "C" fn(Box<GreetingSet>)) {
+pub extern fn sendGreetings(callback: extern "C" fn(&GreetingSet)) {
     let greetings = vec![ Greeting::new("Hello!"), Greeting::new("Hello again!") ];
-    let num_greetings = greetings.len();
 
-    let set = Box::new(GreetingSet {
-        // Get a pointer to the vector as an array, so that we can pass it back to Java
-        greetings: greetings.into_boxed_slice(),
-        // Also return the length of the array, so that we can create the array back in Java
-        number_of_greetings: num_greetings as c_int
-    });
-    callback(set);
+    let set = GreetingSet {
+      // Get a pointer to the vector as an array, so that we can pass it back to Java
+      greetings: greetings.into_boxed_slice()
+    };
+    callback(&set); // Let the callback "borrow" the set. Rust will destroy it after calling the callback
 }
 
 /// Example of returning a more complicated struct from Rust
 #[no_mangle]
 #[allow(non_snake_case)]
-pub extern fn renderGreetings() -> Box<GreetingSet> {
+pub extern fn renderGreetings() -> GreetingSet {
     let greetings = vec![ Greeting::new("Hello!"), Greeting::new("Hello again!") ];
-    let num_greetings = greetings.len();
 
-    Box::new(GreetingSet {
-        greetings: greetings.into_boxed_slice(),
-        number_of_greetings: num_greetings as c_int
-    })
+    GreetingSet {
+        greetings: greetings.into_boxed_slice()
+    }
 }
 
 #[no_mangle]
@@ -179,8 +175,8 @@ pub extern fn dropGreeting(_: Box<Greeting>) {
 
 #[no_mangle]
 #[allow(non_snake_case)]
-pub extern fn dropGreetingSet(_: Box<GreetingSet>) {
-    // Do nothing here. Because we own the GreetingSet here (we're using a Box) and we're not
+pub extern fn dropGreetingSet(_: GreetingSet) {
+    // Do nothing here. Because we own the GreetingSet here and we're not
     // returning it, Rust will assume we don't want it anymore and clean it up.
 }
 
diff --git a/src/test/java/com/github/drrb/javarust/GreetingsTest.java b/src/test/java/com/github/drrb/javarust/GreetingsTest.java
index 469331a..72edb3d 100644
--- a/src/test/java/com/github/drrb/javarust/GreetingsTest.java
+++ b/src/test/java/com/github/drrb/javarust/GreetingsTest.java
@@ -18,16 +18,18 @@
 
 import com.github.drrb.javarust.Greetings.GreetingCallback;
 import com.github.drrb.javarust.Greetings.GreetingSetCallback;
-import static com.github.drrb.javarust.test.Matchers.*;
 import com.github.drrb.javarust.test.MethodPrintingRule;
-import static java.util.Arrays.asList;
-import java.util.LinkedList;
-import java.util.List;
-import static org.junit.Assert.assertThat;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 
+import java.util.LinkedList;
+import java.util.List;
+
+import static com.github.drrb.javarust.test.Matchers.is;
+import static org.hamcrest.Matchers.contains;
+import static org.junit.Assert.assertThat;
+
 public class GreetingsTest {
 
     @Rule
@@ -61,19 +63,17 @@ public void shouldAcceptAStructFromJavaToRust() {
 
     @Test
     public void shouldGetAStructFromRustByValue() {
-        Greeting greeting = library.getGreetingByValue();
-        assertThat(greeting.text, is("Hello from Rust!"));
+        // Using try-with-resources so that memory gets cleaned up. See Greeting.close()
+        try (Greeting greeting = library.getGreetingByValue()) {
+            assertThat(greeting.text, is("Hello from Rust!"));
+        }
     }
 
     @Test
     public void shouldGetAStructFromRustByReference() {
-        Greeting greeting = library.getGreetingByReference();
-
-        assertThat(greeting.text, is("Hello from Rust!"));
-
-        // Free the memory after using it. We need to do this because JNA assumes
-        // that the memory is owned by Rust, so Rust must clean it up.
-        library.dropGreeting(greeting);
+        try (Greeting greeting = library.getGreetingByReference()) {
+            assertThat(greeting.text, is("Hello from Rust!"));
+        }
     }
 
     @Test
@@ -84,7 +84,7 @@ public void apply(String greeting) {
                 greetings.add(greeting);
             }
         });
-        assertThat(greetings, is(asList("Hello there!")));
+        assertThat(greetings, contains("Hello there!"));
     }
 
     @Test
@@ -101,21 +101,18 @@ public void apply(GreetingSet.ByReference greetingSet) {
             greetingStrings.add(greeting.getText());
         }
 
-        assertThat(greetingStrings, is(asList("Hello!", "Hello again!")));
-        for (Greeting greeting: greetings) {
-            library.dropGreeting(greeting);
-        }
+        assertThat(greetingStrings, contains("Hello!", "Hello again!"));
     }
 
     @Test
     public void shouldGetAStructFromRustContainingAnArrayOfStructs() {
-        GreetingSet result = library.renderGreetings();
-        List<String> greetings = new LinkedList<>();
-        for (Greeting greeting: result.getGreetings()) {
-            greetings.add(greeting.getText());
-        }
+        try (GreetingSet.ByValue result = library.renderGreetings()) {
+            List<String> greetings = new LinkedList<>();
+            for (Greeting greeting : result.getGreetings()) {
+                greetings.add(greeting.getText());
+            }
 
-        assertThat(greetings, is(asList("Hello!", "Hello again!")));
-        library.dropGreetingSet(result);
+            assertThat(greetings, contains("Hello!", "Hello again!"));
+        }
     }
 }

From 2ca5fc6ba2dfbe498df91ae4b0c2c6f1363329cc Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Mon, 22 May 2017 21:06:39 +1000
Subject: [PATCH 02/10] Modifying travis config

---
 .travis.yml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 2cd5d1a..98c255b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,10 @@ env:
     - RUST_CHANNEL=stable
     - RUST_CHANNEL=nightly
 before_install:
-  - yes | sudo add-apt-repository ppa:hansjorg/rust
+  - which rustup
+  - which rustup.sh
+  - which rustc
   - sudo apt-get update
+  - apt search rust
 install:
   - sudo apt-get install rust-${RUST_CHANNEL}

From 48570060a5e239e21ccd6a5edfade3eb42d390d4 Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Mon, 22 May 2017 21:09:09 +1000
Subject: [PATCH 03/10] Trying more travis config

---
 .travis.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 98c255b..c5e8c4c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,10 +5,10 @@ env:
     - RUST_CHANNEL=stable
     - RUST_CHANNEL=nightly
 before_install:
-  - which rustup
-  - which rustup.sh
-  - which rustc
+  - which rustup || true
+  - which rustup.sh || true
+  - which rustc || true
   - sudo apt-get update
-  - apt search rust
+  - apt search rust || true
 install:
   - sudo apt-get install rust-${RUST_CHANNEL}

From febe65b394a4dc83fa93f0e96bc2f52bbb50f132 Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Mon, 22 May 2017 21:12:15 +1000
Subject: [PATCH 04/10] Trying more travis config

---
 .travis.yml | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index c5e8c4c..cb26506 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,10 +5,10 @@ env:
     - RUST_CHANNEL=stable
     - RUST_CHANNEL=nightly
 before_install:
-  - which rustup || true
-  - which rustup.sh || true
-  - which rustc || true
-  - sudo apt-get update
-  - apt search rust || true
+  - "which rustup || true"
+  - "which rustup.sh || true"
+  - "which rustc || true"
+  - "sudo apt-get update"
+  - "apt search rust || true"
 install:
   - sudo apt-get install rust-${RUST_CHANNEL}

From f6c74394f0fc3d93e5768b7130f07038c7c1e7d2 Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Mon, 22 May 2017 21:20:22 +1000
Subject: [PATCH 05/10] Try using rustup directly

---
 .travis.yml | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index cb26506..9a40926 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,10 +5,8 @@ env:
     - RUST_CHANNEL=stable
     - RUST_CHANNEL=nightly
 before_install:
-  - "which rustup || true"
-  - "which rustup.sh || true"
-  - "which rustc || true"
-  - "sudo apt-get update"
-  - "apt search rust || true"
+  - "curl https://sh.rustup.rs -sSf > rustup && chmod +x rustup"
+  - "./rustup -y"
+  - "rustc --version"
 install:
-  - sudo apt-get install rust-${RUST_CHANNEL}
+  -  rustup toolchain install ${RUST_CHANNEL}

From 8c27976336276951f9ad66e6305c3cc4d59b7093 Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Tue, 23 May 2017 07:50:48 +1000
Subject: [PATCH 06/10] Add rust to path on Travis

---
 .travis.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.travis.yml b/.travis.yml
index 9a40926..be27188 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,6 +7,7 @@ env:
 before_install:
   - "curl https://sh.rustup.rs -sSf > rustup && chmod +x rustup"
   - "./rustup -y"
+  - "export PATH=$PATH:~/.cargo/bin"
   - "rustc --version"
 install:
   -  rustup toolchain install ${RUST_CHANNEL}

From 2d6dd312eaf4136c54442f2a7b909d9449fce17f Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Tue, 23 May 2017 08:03:19 +1000
Subject: [PATCH 07/10] Override rust version on Travis

---
 .travis.yml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index be27188..d2e66a3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,8 @@ before_install:
   - "curl https://sh.rustup.rs -sSf > rustup && chmod +x rustup"
   - "./rustup -y"
   - "export PATH=$PATH:~/.cargo/bin"
-  - "rustc --version"
+  - rustc --version
 install:
-  -  rustup toolchain install ${RUST_CHANNEL}
+  - rustup toolchain install ${RUST_CHANNEL}
+  - rustup override set ${RUST_CHANNEL}
+  - rustc --version

From 052fd038f3ed071a902e2c4e0c2d46396488f8e9 Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Tue, 23 May 2017 08:09:32 +1000
Subject: [PATCH 08/10] Fixed link line numbers

---
 README.md           | 12 ++++++------
 generate-link-table |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 876a686..e6ee394 100644
--- a/README.md
+++ b/README.md
@@ -29,12 +29,12 @@ and the [Rust code](src/main/rust/com/github/drrb/javarust/lib/greetings.rs). Th
 implementation is heavily commented to explain it.
 
 So far, it contains examples of the following (click the links to see!):
-- *[Arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L46)*: passing simple arguments from Java to Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L45) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L82))
-- *[Return values](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L51)*: returning simple values from Rust to Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L50) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L92))
-- *[Struct arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L57)*: passing structs to Rust from Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L55) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L101))
-- *[Returning structs (2 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L66)*: returning structs from Rust by value and by reference ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L72) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L110))
-- *[Callbacks (3 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L81)*: passing callbacks to Rust that get called from the Rust code ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L85) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L130))
-- *[Freeing memory](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L68)*: freeing memory allocated in Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L115) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L172))
+- *[Arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L45)*: passing simple arguments from Java to Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L44) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L81))
+- *[Return values](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L50)*: returning simple values from Rust to Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L49) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L91))
+- *[Struct arguments](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L56)*: passing structs to Rust from Java ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L54) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L100))
+- *[Returning structs (2 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L65)*: returning structs from Rust by value and by reference ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L71) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L109))
+- *[Callbacks (3 examples)](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L80)*: passing callbacks to Rust that get called from the Rust code ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L84) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L129))
+- *[Freeing memory](src/test/java/com/github/drrb/javarust/GreetingsTest.java#L67)*: freeing memory allocated in Rust ([Java side](src/main/java/com/github/drrb/javarust/Greetings.java#L114) / [Rust side](src/main/rust/com/github/drrb/javarust/lib/greetings.rs#L171))
 
 ## Building and Running the Tests
 
diff --git a/generate-link-table b/generate-link-table
index c6e55c3..f45499d 100755
--- a/generate-link-table
+++ b/generate-link-table
@@ -22,7 +22,7 @@ class Concept < OpenStruct
   private
   def link(text:, regex:, file:)
     line = find_line(regex, file)
-    "[#{text}](#{file}#L#{line + 1})"
+    "[#{text}](#{file}#L#{line})"
   end
 
   def find_line(regex, file)

From 82fd3a22f646876c6185d1384e57a45111102cba Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Tue, 23 May 2017 08:15:22 +1000
Subject: [PATCH 09/10] Allow rust nightly to fail on Travis

---
 .travis.yml | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index d2e66a3..18f1ab6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,12 @@
 language: java
 jdk:
-    - oraclejdk8
+  - oraclejdk8
 env:
-    - RUST_CHANNEL=stable
-    - RUST_CHANNEL=nightly
+  - RUST_CHANNEL=stable
+  - RUST_CHANNEL=nightly
+matrix:
+    allow_failures:
+      - env: RUST_CHANNEL=nightly
 before_install:
   - "curl https://sh.rustup.rs -sSf > rustup && chmod +x rustup"
   - "./rustup -y"

From aaf989677b1976aaf9c46117554c7da0b311d0ef Mon Sep 17 00:00:00 2001
From: drrb <drrrrrrrrrrrb@gmail.com>
Date: Wed, 16 Aug 2017 18:51:33 +1000
Subject: [PATCH 10/10] Fixed dropping of GreetingSet

We were incorrectly passing GreetingSet by value, which was causing problems when we tried to free it.
---
 .../com/github/drrb/javarust/Greeting.java    |  5 ++++
 .../com/github/drrb/javarust/GreetingSet.java | 28 +++++++++++++------
 .../com/github/drrb/javarust/Greetings.java   |  4 +--
 .../com/github/drrb/javarust/lib/greetings.rs |  8 +++---
 .../github/drrb/javarust/GreetingsTest.java   |  4 +--
 5 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/src/main/java/com/github/drrb/javarust/Greeting.java b/src/main/java/com/github/drrb/javarust/Greeting.java
index aa3ec61..020a80d 100644
--- a/src/main/java/com/github/drrb/javarust/Greeting.java
+++ b/src/main/java/com/github/drrb/javarust/Greeting.java
@@ -49,6 +49,11 @@ protected List<String> getFieldOrder() {
 
     @Override
     public void close() {
+        // Turn off "auto-synch". If it is on, JNA will automatically read all fields
+        // from the struct's memory and update them on the Java object. This synchronization
+        // occurs after every native method call. If it occurs after we drop the struct, JNA
+        // will try to read from the freed memory and cause a segmentation fault.
+        setAutoSynch(false);
         // Send the struct back to rust for the memory to be freed
         Greetings.INSTANCE.dropGreeting(this);
     }
diff --git a/src/main/java/com/github/drrb/javarust/GreetingSet.java b/src/main/java/com/github/drrb/javarust/GreetingSet.java
index 06ed511..f793131 100644
--- a/src/main/java/com/github/drrb/javarust/GreetingSet.java
+++ b/src/main/java/com/github/drrb/javarust/GreetingSet.java
@@ -26,18 +26,12 @@
  * A struct that contains an array of structs. This is the Java representation
  * of the GreetingSet struct in Rust (see the Rust code).
  */
-public class GreetingSet extends Structure {
+public class GreetingSet extends Structure implements Closeable {
 
     public static class ByReference extends GreetingSet implements Structure.ByReference {
     }
 
-    public static class ByValue extends GreetingSet implements Structure.ByValue, Closeable {
-
-        @Override
-        public void close() {
-            Greetings.INSTANCE.dropGreetingSet(this);
-        }
-
+    public static class ByValue extends GreetingSet implements Structure.ByValue {
     }
 
     /**
@@ -48,7 +42,7 @@ public void close() {
      * 
      * NB: We need to explicitly specify that the field is a pointer (i.e. we need
      * to use ByReference) because, by default, JNA assumes that struct fields 
-     * are not pointers (i.e. the if you just say "Greeting", JNA assumes 
+     * are not pointers (i.e. if you just say "Greeting", JNA assumes
      * "Greeting.ByValue" here).
      */
     public Greeting.ByReference greetings;
@@ -88,4 +82,20 @@ public List<Greeting> getGreetings() {
     protected List<String> getFieldOrder() {
         return Arrays.asList("greetings", "numberOfGreetings");
     }
+
+    /**
+     * Send the GreetingSet back to Rust to be dropped.
+     *
+     * We do this because JNA doesn't free the memory when the object is garbage collected.
+     */
+    @Override
+    public void close() {
+        // Turn off "auto-synch". If it is on, JNA will automatically read all fields
+        // from the struct's memory and update them on the Java object. This synchronization
+        // occurs after every native method call. If it occurs after we drop the struct, JNA
+        // will try to read from the freed memory and cause a segmentation fault.
+        setAutoSynch(false);
+        // Send the struct back to rust for the memory to be freed
+        Greetings.INSTANCE.dropGreetingSet(this);
+    }
 }
diff --git a/src/main/java/com/github/drrb/javarust/Greetings.java b/src/main/java/com/github/drrb/javarust/Greetings.java
index aa65fc6..c395be5 100644
--- a/src/main/java/com/github/drrb/javarust/Greetings.java
+++ b/src/main/java/com/github/drrb/javarust/Greetings.java
@@ -76,7 +76,7 @@ public interface Greetings extends Library {
      * This is the same as returning a {@link GreetingSet.ByReference}. JNA assumes
      * it's by reference when it's returned from a native function.
      */
-    GreetingSet.ByValue renderGreetings();
+    GreetingSet renderGreetings();
 
     /**
      * Passing a callback that will be called from Rust with individual strings
@@ -116,5 +116,5 @@ interface GreetingSetCallback extends Callback {
     /**
      * Free the memory used by a GreetingSet
      */
-    void dropGreetingSet(GreetingSet.ByValue greetingSet);
+    void dropGreetingSet(GreetingSet greetingSet);
 }
diff --git a/src/main/rust/com/github/drrb/javarust/lib/greetings.rs b/src/main/rust/com/github/drrb/javarust/lib/greetings.rs
index ec00661..213c7b1 100644
--- a/src/main/rust/com/github/drrb/javarust/lib/greetings.rs
+++ b/src/main/rust/com/github/drrb/javarust/lib/greetings.rs
@@ -158,12 +158,12 @@ pub extern fn sendGreetings(callback: extern "C" fn(&GreetingSet)) {
 /// Example of returning a more complicated struct from Rust
 #[no_mangle]
 #[allow(non_snake_case)]
-pub extern fn renderGreetings() -> GreetingSet {
+pub extern fn renderGreetings() -> Box<GreetingSet> {
     let greetings = vec![ Greeting::new("Hello!"), Greeting::new("Hello again!") ];
 
-    GreetingSet {
+    Box::new(GreetingSet {
         greetings: greetings.into_boxed_slice()
-    }
+    })
 }
 
 #[no_mangle]
@@ -175,7 +175,7 @@ pub extern fn dropGreeting(_: Box<Greeting>) {
 
 #[no_mangle]
 #[allow(non_snake_case)]
-pub extern fn dropGreetingSet(_: GreetingSet) {
+pub extern fn dropGreetingSet(_: Box<GreetingSet>) {
     // Do nothing here. Because we own the GreetingSet here and we're not
     // returning it, Rust will assume we don't want it anymore and clean it up.
 }
diff --git a/src/test/java/com/github/drrb/javarust/GreetingsTest.java b/src/test/java/com/github/drrb/javarust/GreetingsTest.java
index 72edb3d..0cb09e8 100644
--- a/src/test/java/com/github/drrb/javarust/GreetingsTest.java
+++ b/src/test/java/com/github/drrb/javarust/GreetingsTest.java
@@ -97,7 +97,7 @@ public void apply(GreetingSet.ByReference greetingSet) {
         });
 
         List<String> greetingStrings = new LinkedList<>();
-        for (Greeting greeting: greetings) {
+        for (Greeting greeting : greetings) {
             greetingStrings.add(greeting.getText());
         }
 
@@ -106,7 +106,7 @@ public void apply(GreetingSet.ByReference greetingSet) {
 
     @Test
     public void shouldGetAStructFromRustContainingAnArrayOfStructs() {
-        try (GreetingSet.ByValue result = library.renderGreetings()) {
+        try (GreetingSet result = library.renderGreetings()) {
             List<String> greetings = new LinkedList<>();
             for (Greeting greeting : result.getGreetings()) {
                 greetings.add(greeting.getText());