Rework how Rust generated files are laid out (#6731)

* Refactored Rust Generated code into a module directory.

Each symbol will be generated into one file and then
imported into a module. This breaks the "out_dir"
pattern where some users would generate code in their
target/ directory. Also, these objects are best used
in their own module. It will be hard for users to share
their own module structure with flatbuffers namespaces.

There may be solutions to these drawbacks but that should
be discussed. I don't want to overengineer here.

* shadow error

* try fix .bat file

* fix .bat 2

* Restore accidentally deleted files

* Fixed some DONOTSUBMITs and made Rust outdir pattern use symlinks.

* fixed binary files

* git clang format

* make generated onefiles not public and fix .bat

* reduced diff with master in generate_code.sh

* fix shadowed variable

* add object api flags to .bat

* space

* Removed extern crate and extra &

* use statement

* more clippy lints

* format

* Undo extern crate -> use change, it actually matters to our tests

Co-authored-by: Casper Neo <cneo@google.com>

tests/more_defaults/abc_generated.rs

@@ -0,0 +1,97 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MIN_ABC: i32 = 0;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MAX_ABC: i32 = 2;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+#[allow(non_camel_case_types)]
+pub const ENUM_VALUES_ABC: [ABC; 3] = [
+  ABC::A,
+  ABC::B,
+  ABC::C,
+];
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+#[repr(transparent)]
+pub struct ABC(pub i32);
+#[allow(non_upper_case_globals)]
+impl ABC {
+  pub const A: Self = Self(0);
+  pub const B: Self = Self(1);
+  pub const C: Self = Self(2);
+
+  pub const ENUM_MIN: i32 = 0;
+  pub const ENUM_MAX: i32 = 2;
+  pub const ENUM_VALUES: &'static [Self] = &[
+    Self::A,
+    Self::B,
+    Self::C,
+  ];
+  /// Returns the variant's name or "" if unknown.
+  pub fn variant_name(self) -> Option<&'static str> {
+    match self {
+      Self::A => Some("A"),
+      Self::B => Some("B"),
+      Self::C => Some("C"),
+      _ => None,
+    }
+  }
+}
+impl std::fmt::Debug for ABC {
+  fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    if let Some(name) = self.variant_name() {
+      f.write_str(name)
+    } else {
+      f.write_fmt(format_args!("<UNKNOWN {:?}>", self.0))
+    }
+  }
+}
+impl<'a> flatbuffers::Follow<'a> for ABC {
+  type Inner = Self;
+  #[inline]
+  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+    let b = unsafe {
+      flatbuffers::read_scalar_at::<i32>(buf, loc)
+    };
+    Self(b)
+  }
+}
+
+impl flatbuffers::Push for ABC {
+    type Output = ABC;
+    #[inline]
+    fn push(&self, dst: &mut [u8], _rest: &[u8]) {
+        unsafe { flatbuffers::emplace_scalar::<i32>(dst, self.0); }
+    }
+}
+
+impl flatbuffers::EndianScalar for ABC {
+  #[inline]
+  fn to_little_endian(self) -> Self {
+    let b = i32::to_le(self.0);
+    Self(b)
+  }
+  #[inline]
+  #[allow(clippy::wrong_self_convention)]
+  fn from_little_endian(self) -> Self {
+    let b = i32::from_le(self.0);
+    Self(b)
+  }
+}
+
+impl<'a> flatbuffers::Verifiable for ABC {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    i32::run_verifier(v, pos)
+  }
+}
+
+impl flatbuffers::SimpleToVerifyInSlice for ABC {}

tests/more_defaults/mod.rs

@@ -0,0 +1,5 @@
+// Automatically generated by the Flatbuffers compiler. Do not modify.
+mod abc_generated;
+pub use self::abc_generated::*;
+mod more_defaults_generated;
+pub use self::more_defaults_generated::*;

tests/more_defaults/more_defaults_generated.rs

@@ -0,0 +1,266 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+pub enum MoreDefaultsOffset {}
+#[derive(Copy, Clone, PartialEq)]
+
+pub struct MoreDefaults<'a> {
+  pub _tab: flatbuffers::Table<'a>,
+}
+
+impl<'a> flatbuffers::Follow<'a> for MoreDefaults<'a> {
+    type Inner = MoreDefaults<'a>;
+    #[inline]
+    fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+        Self { _tab: flatbuffers::Table { buf, loc } }
+    }
+}
+
+impl<'a> MoreDefaults<'a> {
+    pub const fn get_fully_qualified_name() -> &'static str {
+        "MoreDefaults"
+    }
+
+    #[inline]
+    pub fn init_from_table(table: flatbuffers::Table<'a>) -> Self {
+        MoreDefaults { _tab: table }
+    }
+    #[allow(unused_mut)]
+    pub fn create<'bldr: 'args, 'args: 'mut_bldr, 'mut_bldr>(
+        _fbb: &'mut_bldr mut flatbuffers::FlatBufferBuilder<'bldr>,
+        args: &'args MoreDefaultsArgs<'args>) -> flatbuffers::WIPOffset<MoreDefaults<'bldr>> {
+      let mut builder = MoreDefaultsBuilder::new(_fbb);
+      if let Some(x) = args.bools { builder.add_bools(x); }
+      if let Some(x) = args.abcs { builder.add_abcs(x); }
+      if let Some(x) = args.some_string { builder.add_some_string(x); }
+      if let Some(x) = args.empty_string { builder.add_empty_string(x); }
+      if let Some(x) = args.floats { builder.add_floats(x); }
+      if let Some(x) = args.ints { builder.add_ints(x); }
+      builder.finish()
+    }
+
+    pub fn unpack(&self) -> MoreDefaultsT {
+      let ints = {
+        let x = self.ints();
+        x.into_iter().collect()
+      };
+      let floats = {
+        let x = self.floats();
+        x.into_iter().collect()
+      };
+      let empty_string = {
+        let x = self.empty_string();
+        x.to_string()
+      };
+      let some_string = {
+        let x = self.some_string();
+        x.to_string()
+      };
+      let abcs = {
+        let x = self.abcs();
+        x.into_iter().collect()
+      };
+      let bools = {
+        let x = self.bools();
+        x.to_vec()
+      };
+      MoreDefaultsT {
+        ints,
+        floats,
+        empty_string,
+        some_string,
+        abcs,
+        bools,
+      }
+    }
+    pub const VT_INTS: flatbuffers::VOffsetT = 4;
+    pub const VT_FLOATS: flatbuffers::VOffsetT = 6;
+    pub const VT_EMPTY_STRING: flatbuffers::VOffsetT = 8;
+    pub const VT_SOME_STRING: flatbuffers::VOffsetT = 10;
+    pub const VT_ABCS: flatbuffers::VOffsetT = 12;
+    pub const VT_BOOLS: flatbuffers::VOffsetT = 14;
+
+  #[inline]
+  pub fn ints(&self) -> flatbuffers::Vector<'a, i32> {
+    self._tab.get::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'a, i32>>>(MoreDefaults::VT_INTS, Some(Default::default())).unwrap()
+  }
+  #[inline]
+  pub fn floats(&self) -> flatbuffers::Vector<'a, f32> {
+    self._tab.get::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'a, f32>>>(MoreDefaults::VT_FLOATS, Some(Default::default())).unwrap()
+  }
+  #[inline]
+  pub fn empty_string(&self) -> &'a str {
+    self._tab.get::<flatbuffers::ForwardsUOffset<&str>>(MoreDefaults::VT_EMPTY_STRING, Some(&"")).unwrap()
+  }
+  #[inline]
+  pub fn some_string(&self) -> &'a str {
+    self._tab.get::<flatbuffers::ForwardsUOffset<&str>>(MoreDefaults::VT_SOME_STRING, Some(&"some")).unwrap()
+  }
+  #[inline]
+  pub fn abcs(&self) -> flatbuffers::Vector<'a, ABC> {
+    self._tab.get::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'a, ABC>>>(MoreDefaults::VT_ABCS, Some(Default::default())).unwrap()
+  }
+  #[inline]
+  pub fn bools(&self) -> &'a [bool] {
+    self._tab.get::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'a, bool>>>(MoreDefaults::VT_BOOLS, Some(Default::default())).map(|v| v.safe_slice()).unwrap()
+  }
+}
+
+impl flatbuffers::Verifiable for MoreDefaults<'_> {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    v.visit_table(pos)?
+     .visit_field::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'_, i32>>>("ints", Self::VT_INTS, false)?
+     .visit_field::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'_, f32>>>("floats", Self::VT_FLOATS, false)?
+     .visit_field::<flatbuffers::ForwardsUOffset<&str>>("empty_string", Self::VT_EMPTY_STRING, false)?
+     .visit_field::<flatbuffers::ForwardsUOffset<&str>>("some_string", Self::VT_SOME_STRING, false)?
+     .visit_field::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'_, ABC>>>("abcs", Self::VT_ABCS, false)?
+     .visit_field::<flatbuffers::ForwardsUOffset<flatbuffers::Vector<'_, bool>>>("bools", Self::VT_BOOLS, false)?
+     .finish();
+    Ok(())
+  }
+}
+pub struct MoreDefaultsArgs<'a> {
+    pub ints: Option<flatbuffers::WIPOffset<flatbuffers::Vector<'a, i32>>>,
+    pub floats: Option<flatbuffers::WIPOffset<flatbuffers::Vector<'a, f32>>>,
+    pub empty_string: Option<flatbuffers::WIPOffset<&'a str>>,
+    pub some_string: Option<flatbuffers::WIPOffset<&'a str>>,
+    pub abcs: Option<flatbuffers::WIPOffset<flatbuffers::Vector<'a, ABC>>>,
+    pub bools: Option<flatbuffers::WIPOffset<flatbuffers::Vector<'a, bool>>>,
+}
+impl<'a> Default for MoreDefaultsArgs<'a> {
+    #[inline]
+    fn default() -> Self {
+        MoreDefaultsArgs {
+            ints: None,
+            floats: None,
+            empty_string: None,
+            some_string: None,
+            abcs: None,
+            bools: None,
+        }
+    }
+}
+pub struct MoreDefaultsBuilder<'a: 'b, 'b> {
+  fbb_: &'b mut flatbuffers::FlatBufferBuilder<'a>,
+  start_: flatbuffers::WIPOffset<flatbuffers::TableUnfinishedWIPOffset>,
+}
+impl<'a: 'b, 'b> MoreDefaultsBuilder<'a, 'b> {
+  #[inline]
+  pub fn add_ints(&mut self, ints: flatbuffers::WIPOffset<flatbuffers::Vector<'b , i32>>) {
+    self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>(MoreDefaults::VT_INTS, ints);
+  }
+  #[inline]
+  pub fn add_floats(&mut self, floats: flatbuffers::WIPOffset<flatbuffers::Vector<'b , f32>>) {
+    self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>(MoreDefaults::VT_FLOATS, floats);
+  }
+  #[inline]
+  pub fn add_empty_string(&mut self, empty_string: flatbuffers::WIPOffset<&'b  str>) {
+    self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>(MoreDefaults::VT_EMPTY_STRING, empty_string);
+  }
+  #[inline]
+  pub fn add_some_string(&mut self, some_string: flatbuffers::WIPOffset<&'b  str>) {
+    self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>(MoreDefaults::VT_SOME_STRING, some_string);
+  }
+  #[inline]
+  pub fn add_abcs(&mut self, abcs: flatbuffers::WIPOffset<flatbuffers::Vector<'b , ABC>>) {
+    self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>(MoreDefaults::VT_ABCS, abcs);
+  }
+  #[inline]
+  pub fn add_bools(&mut self, bools: flatbuffers::WIPOffset<flatbuffers::Vector<'b , bool>>) {
+    self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>(MoreDefaults::VT_BOOLS, bools);
+  }
+  #[inline]
+  pub fn new(_fbb: &'b mut flatbuffers::FlatBufferBuilder<'a>) -> MoreDefaultsBuilder<'a, 'b> {
+    let start = _fbb.start_table();
+    MoreDefaultsBuilder {
+      fbb_: _fbb,
+      start_: start,
+    }
+  }
+  #[inline]
+  pub fn finish(self) -> flatbuffers::WIPOffset<MoreDefaults<'a>> {
+    let o = self.fbb_.end_table(self.start_);
+    flatbuffers::WIPOffset::new(o.value())
+  }
+}
+
+impl std::fmt::Debug for MoreDefaults<'_> {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    let mut ds = f.debug_struct("MoreDefaults");
+      ds.field("ints", &self.ints());
+      ds.field("floats", &self.floats());
+      ds.field("empty_string", &self.empty_string());
+      ds.field("some_string", &self.some_string());
+      ds.field("abcs", &self.abcs());
+      ds.field("bools", &self.bools());
+      ds.finish()
+  }
+}
+#[non_exhaustive]
+#[derive(Debug, Clone, PartialEq)]
+pub struct MoreDefaultsT {
+  pub ints: Vec<i32>,
+  pub floats: Vec<f32>,
+  pub empty_string: String,
+  pub some_string: String,
+  pub abcs: Vec<ABC>,
+  pub bools: Vec<bool>,
+}
+impl Default for MoreDefaultsT {
+  fn default() -> Self {
+    Self {
+      ints: Default::default(),
+      floats: Default::default(),
+      empty_string: "".to_string(),
+      some_string: "some".to_string(),
+      abcs: Default::default(),
+      bools: Default::default(),
+    }
+  }
+}
+impl MoreDefaultsT {
+  pub fn pack<'b>(
+    &self,
+    _fbb: &mut flatbuffers::FlatBufferBuilder<'b>
+  ) -> flatbuffers::WIPOffset<MoreDefaults<'b>> {
+    let ints = Some({
+      let x = &self.ints;
+      _fbb.create_vector(x)
+    });
+    let floats = Some({
+      let x = &self.floats;
+      _fbb.create_vector(x)
+    });
+    let empty_string = Some({
+      let x = &self.empty_string;
+      _fbb.create_string(x)
+    });
+    let some_string = Some({
+      let x = &self.some_string;
+      _fbb.create_string(x)
+    });
+    let abcs = Some({
+      let x = &self.abcs;
+      _fbb.create_vector(x)
+    });
+    let bools = Some({
+      let x = &self.bools;
+      _fbb.create_vector(x)
+    });
+    MoreDefaults::create(_fbb, &MoreDefaultsArgs{
+      ints,
+      floats,
+      empty_string,
+      some_string,
+      abcs,
+      bools,
+    })
+  }
+}