Add codegen backend for Ruby.

This commit adds support for `uniffi-bindgen -l ruby` to generate
a Ruby module from a UniFFI Rust component.

CHANGELOG.md

@@ -14,6 +14,11 @@
 
 ### What's New
 
+- A new **Ruby** codegen backend has been added. You can now call `uniffi-bindgen -l ruby` to
+  generate a Ruby module that wraps a UniFFI Rust component. Thanks to @saks for contributing
+  this backend!
+    - When running `cargo test` locally, you will need a recent version of Ruby and
+      the `ffi` gem in order to successfully execute the Ruby backend tests.
 - Threadsafe Object methods can now use `self: Arc<Self>` as the method receiver in the underlying
   Rust code, in addition to the default `self: &Self`. To do so, annotate the method with
   `[Self=ByArc]` in the `.udl` file and update the corresponding Rust method signature to match.

examples/arithmetic/tests/bindings/test_arithmetic.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'test/unit'
+require 'arithmetic'
+
+include Test::Unit::Assertions
+
+assert_raise Arithmetic::ArithmeticError::IntegerOverflow do
+  Arithmetic.add 18_446_744_073_709_551_615, 1
+end
+
+assert_equal Arithmetic.add(2, 4), 6
+assert_equal Arithmetic.add(4, 8), 12
+
+assert_raise Arithmetic::ArithmeticError::IntegerOverflow do
+  Arithmetic.sub 0, 1
+end
+
+assert_equal Arithmetic.sub(4, 2), 2
+assert_equal Arithmetic.sub(8, 4), 4
+assert_equal Arithmetic.div(8, 4), 2
+
+assert_raise Arithmetic::InternalError do
+  Arithmetic.div 8, 0
+end
+
+assert Arithmetic.equal(2, 2)
+assert Arithmetic.equal(4, 4)
+
+assert !Arithmetic.equal(2, 4)
+assert !Arithmetic.equal(4, 8)

examples/arithmetic/tests/test_generated_bindings.rs

@@ -1,6 +1,7 @@
 uniffi_macros::build_foreign_language_testcases!(
     "src/arithmetic.udl",
     [
+        "tests/bindings/test_arithmetic.rb",
         "tests/bindings/test_arithmetic.py",
         "tests/bindings/test_arithmetic.kts",
         "tests/bindings/test_arithmetic.swift",

examples/arithmetic/uniffi.toml

@@ -5,5 +5,8 @@ cdylib_name = "arithmetical"
 [bindings.python]
 cdylib_name = "arithmetical"
 
+[bindings.ruby]
+cdylib_name = "arithmetical"
+
 [bindings.swift]
 cdylib_name = "arithmetical"

examples/geometry/tests/bindings/test_geometry.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'test/unit'
+require 'geometry'
+
+include Test::Unit::Assertions
+include Geometry
+
+ln1 = Line.new(Point.new(0.0, 0.0), Point.new(1.0, 2.0))
+ln2 = Line.new(Point.new(1.0, 1.0), Point.new(2.0, 2.0))
+
+assert_equal Geometry.gradient(ln1), 2
+assert_equal Geometry.gradient(ln2), 1
+
+assert_equal Geometry.intersection(ln1, ln2), Point.new(0, 0)
+assert Geometry.intersection(ln1, ln1).nil?

examples/geometry/tests/test_generated_bindings.rs

@@ -2,6 +2,7 @@ uniffi_macros::build_foreign_language_testcases!(
     "src/geometry.udl",
     [
         "tests/bindings/test_geometry.py",
+        "tests/bindings/test_geometry.rb",
         "tests/bindings/test_geometry.kts",
         "tests/bindings/test_geometry.swift",
     ]

examples/rondpoint/tests/bindings/test_rondpoint.rb

@@ -0,0 +1,142 @@
+# frozen_string_literal: true
+
+require 'test/unit'
+require 'rondpoint'
+
+include Test::Unit::Assertions
+include Rondpoint
+
+dico = Dictionnaire.new Enumeration::DEUX, true, 0, 123_456_789
+
+assert_equal dico, Rondpoint.copie_dictionnaire(dico)
+
+assert_equal Rondpoint.copie_enumeration(Enumeration::DEUX), Enumeration::DEUX
+
+assert_equal Rondpoint.copie_enumerations([
+                                            Enumeration::UN,
+                                            Enumeration::DEUX
+                                          ]), [Enumeration::UN, Enumeration::DEUX]
+
+assert_equal Rondpoint.copie_carte({
+                                     '0' => EnumerationAvecDonnees::ZERO.new,
+                                     '1' => EnumerationAvecDonnees::UN.new(1),
+                                     '2' => EnumerationAvecDonnees::DEUX.new(2, 'deux')
+                                   }), {
+                                     '0' => EnumerationAvecDonnees::ZERO.new,
+                                     '1' => EnumerationAvecDonnees::UN.new(1),
+                                     '2' => EnumerationAvecDonnees::DEUX.new(2, 'deux')
+                                   }
+
+assert Rondpoint.switcheroo(false)
+
+assert_not_equal EnumerationAvecDonnees::ZERO.new, EnumerationAvecDonnees::UN.new(1)
+assert_equal EnumerationAvecDonnees::UN.new(1), EnumerationAvecDonnees::UN.new(1)
+assert_not_equal EnumerationAvecDonnees::UN.new(1), EnumerationAvecDonnees::UN.new(2)
+
+# Test the roundtrip across the FFI.
+# This shows that the values we send come back in exactly the same state as we sent them.
+# i.e. it shows that lowering from ruby and lifting into rust is symmetrical with
+#      lowering from rust and lifting into ruby.
+RT = Retourneur.new
+
+def affirm_aller_retour(vals, fn_name)
+  vals.each do |v|
+    id_v = RT.public_send fn_name, v
+
+    assert_equal id_v, v, "Round-trip failure: #{v} => #{id_v}"
+  end
+end
+
+MIN_I8 = -1 * 2**7
+MAX_I8 = 2**7 - 1
+MIN_I16 = -1 * 2**15
+MAX_I16 = 2**15 - 1
+MIN_I32 = -1 * 2**31
+MAX_I32 = 2**31 - 1
+MIN_I64 = -1 * 2**31
+MAX_I64 = 2**31 - 1
+
+# Ruby floats are always doubles, so won't round-trip through f32 correctly.
+# This truncates them appropriately.
+F32_ONE_THIRD = [1.0 / 3].pack('f').unpack('f')[0]
+
+# Booleans
+affirm_aller_retour([true, false], :identique_boolean)
+
+# Bytes.
+affirm_aller_retour([MIN_I8, -1, 0, 1, MAX_I8], :identique_i8)
+affirm_aller_retour([0x00, 0x12, 0xFF], :identique_u8)
+
+# Shorts
+affirm_aller_retour([MIN_I16, -1, 0, 1, MAX_I16], :identique_i16)
+affirm_aller_retour([0x0000, 0x1234, 0xFFFF], :identique_u16)
+
+# Ints
+affirm_aller_retour([MIN_I32, -1, 0, 1, MAX_I32], :identique_i32)
+affirm_aller_retour([0x00000000, 0x12345678, 0xFFFFFFFF], :identique_u32)
+
+# Longs
+affirm_aller_retour([MIN_I64, -1, 0, 1, MAX_I64], :identique_i64)
+affirm_aller_retour([0x0000000000000000, 0x1234567890ABCDEF, 0xFFFFFFFFFFFFFFFF], :identique_u64)
+
+# Floats
+affirm_aller_retour([0.0, 0.5, 0.25, 1.0, F32_ONE_THIRD], :identique_float)
+
+# Doubles
+affirm_aller_retour(
+  [0.0, 0.5, 0.25, 1.0, 1.0 / 3, Float::MAX, Float::MIN],
+  :identique_double
+)
+
+# Strings
+affirm_aller_retour(
+  ['', 'abc', 'été', 'ښي لاس ته لوستلو لوستل',
+   '😻emoji 👨‍👧‍👦multi-emoji, 🇨🇭a flag, a canal, panama'],
+  :identique_string
+)
+
+# Test one way across the FFI.
+#
+# We send one representation of a value to lib.rs, and it transforms it into another, a string.
+# lib.rs sends the string back, and then we compare here in ruby.
+#
+# This shows that the values are transformed into strings the same way in both ruby and rust.
+# i.e. if we assume that the string return works (we test this assumption elsewhere)
+#      we show that lowering from ruby and lifting into rust has values that both ruby and rust
+#      both stringify in the same way. i.e. the same values.
+#
+# If we roundtripping proves the symmetry of our lowering/lifting from here to rust, and lowering/lifting from rust to here,
+# and this convinces us that lowering/lifting from here to rust is correct, then
+# together, we've shown the correctness of the return leg.
+ST = Stringifier.new
+
+def affirm_enchaine(vals, fn_name)
+  vals.each do |v|
+    str_v = ST.public_send fn_name, v
+
+    assert_equal v.to_s, str_v, "String compare error #{v} => #{str_v}"
+  end
+end
+
+# Test the efficacy of the string transport from rust. If this fails, but everything else
+# works, then things are very weird.
+assert_equal ST.well_known_string('ruby'), 'uniffi 💚 ruby!'
+
+# Booleans
+affirm_enchaine([true, false], :to_string_boolean)
+
+# Bytes.
+affirm_enchaine([MIN_I8, -1, 0, 1, MAX_I8], :to_string_i8)
+affirm_enchaine([0x00, 0x12, 0xFF], :to_string_u8)
+
+# Shorts
+affirm_enchaine([MIN_I16, -1, 0, 1, MAX_I16], :to_string_i16)
+affirm_enchaine([0x0000, 0x1234, 0xFFFF], :to_string_u16)
+
+# Ints
+affirm_enchaine([MIN_I32, -1, 0, 1, MAX_I32], :to_string_i32)
+affirm_enchaine([0x00000000, 0x12345678, 0xFFFFFFFF], :to_string_u32)
+
+# Longs
+affirm_enchaine([MIN_I64, -1, 0, 1, MAX_I64], :to_string_i64)
+affirm_enchaine([0x0000000000000000, 0x1234567890ABCDEF, 0xFFFFFFFFFFFFFFFF], :to_string_u64)

examples/rondpoint/tests/test_generated_bindings.rs

@@ -4,5 +4,6 @@ uniffi_macros::build_foreign_language_testcases!(
         "tests/bindings/test_rondpoint.kts",
         "tests/bindings/test_rondpoint.swift",
         "tests/bindings/test_rondpoint.py",
+        "tests/bindings/test_rondpoint.rb",
     ]
 );

examples/sprites/tests/bindings/test_sprites.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require 'test/unit'
+require 'sprites'
+
+include Test::Unit::Assertions
+include Sprites
+
+sempty = Sprite.new(nil)
+assert_equal sempty.get_position, Point.new(0, 0)
+
+s = Sprite.new(Point.new(0, 1))
+assert_equal s.get_position, Point.new(0, 1)
+
+s.move_to(Point.new(1, 2))
+assert_equal s.get_position, Point.new(1, 2)
+
+s.move_by(Vector.new(-4, 2))
+assert_equal s.get_position, Point.new(-3, 4)
+
+srel = Sprite.new_relative_to(Point.new(0, 1), Vector.new(1, 1.5))
+assert_equal srel.get_position, Point.new(1, 2.5)

examples/sprites/tests/test_generated_bindings.rs

@@ -2,6 +2,7 @@ uniffi_macros::build_foreign_language_testcases!(
     "src/sprites.udl",
     [
         "tests/bindings/test_sprites.py",
+        "tests/bindings/test_sprites.rb",
         "tests/bindings/test_sprites.kts",
         "tests/bindings/test_sprites.swift",
     ]

examples/todolist/tests/bindings/test_todolist.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require 'test/unit'
+require 'todolist'
+
+include Test::Unit::Assertions
+include Todolist
+
+todo = TodoList.new
+entry = TodoEntry.new 'Write bindings for strings in records'
+
+todo.add_item('Write ruby bindings')
+
+assert_equal todo.get_last, 'Write ruby bindings'
+
+todo.add_item('Write tests for bindings')
+
+assert_equal todo.get_last, 'Write tests for bindings'
+
+todo.add_entry(entry)
+
+assert_equal todo.get_last, 'Write bindings for strings in records'
+assert_equal todo.get_last_entry.text, 'Write bindings for strings in records'
+
+todo.add_item("Test Ünicode hàndling without an entry can't believe I didn't test this at first 🤣")
+assert_equal todo.get_last, "Test Ünicode hàndling without an entry can't believe I didn't test this at first 🤣"
+
+entry2 = TodoEntry.new("Test Ünicode hàndling in an entry can't believe I didn't test this at first 🤣")
+todo.add_entry(entry2)
+assert_equal todo.get_last_entry.text, "Test Ünicode hàndling in an entry can't believe I didn't test this at first 🤣"

examples/todolist/tests/test_generated_bindings.rs

@@ -3,6 +3,7 @@ uniffi_macros::build_foreign_language_testcases!(
     [
         "tests/bindings/test_todolist.kts",
         "tests/bindings/test_todolist.swift",
+        "tests/bindings/test_todolist.rb",
         "tests/bindings/test_todolist.py"
     ]
 );