executor: move into `tokio` crate (#1702)

A step towards collapsing Tokio sub crates into a single `tokio`
crate (#1318).

The executor implementation is now provided by the main `tokio` crate.
Functionality can be opted out of by using the various net related
feature flags.

101 files changed, 387 insertions, 690 deletions

diff --git a/Cargo.toml b/Cargo.toml
index d6703e16..4a9e88a0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,6 @@
 
 members = [
   "tokio",
-  "tokio-executor",
   "tokio-macros",
   "tokio-sync",
   "tokio-test",
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 5b3188ea..4fb21761 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -47,9 +47,6 @@ jobs:
     displayName: Test sub crates -
     rust: beta
     crates:
-      tokio-executor:
-        - current-thread
-        - thread-pool
       tokio-sync:
         - async-traits
       tokio-macros: []
@@ -58,22 +55,23 @@ jobs:
       examples: []
 
 # Test compilation failure
-- template: ci/azure-test-stable.yml
-  parameters:
-    name: test_features
-    displayName: Test feature flags
-    rust: beta
-    crates:
-      tests-build:
-        - tokio-executor
-        - executor-without-current-thread
-        # - macros-invalid-input
-        # - net-no-features
-        # - net-with-tcp
-        # - net-with-udp
-        # - net-with-uds
-        # - tokio-no-features
-        # - tokio-with-net
+# Disable pending: https://github.com/tokio-rs/tokio/pull/1695#issuecomment-547045383
+# - template: ci/azure-test-stable.yml
+#   parameters:
+#     name: test_features
+#     displayName: Test feature flags
+#     rust: beta
+#     crates:
+#       tests-build:
+#         # - tokio-executor
+#         # - executor-without-current-thread
+#         # - macros-invalid-input
+#         # - net-no-features
+#         # - net-with-tcp
+#         # - net-with-udp
+#         # - net-with-uds
+#         # - tokio-no-features
+#         # - tokio-with-net
 
 # Run loom tests
 - template: ci/azure-loom.yml
@@ -81,7 +79,6 @@ jobs:
     name: loom
     rust: beta
     crates:
-      - tokio-executor
       - tokio
 
 # Try cross compiling
@@ -115,7 +112,7 @@ jobs:
       - clippy
       - test_tokio
       - test_linux
-      - test_features
+      # - test_features
       - loom
 #      - test_nightly
       - cross
diff --git a/ci/azure-tsan.yml b/ci/azure-tsan.yml
index 3ce24ee8..0104697e 100644
--- a/ci/azure-tsan.yml
+++ b/ci/azure-tsan.yml
@@ -5,8 +5,6 @@ jobs:
     matrix:
       Timer:
         cmd: cargo test -p tokio-timer --test hammer
-      Threadpool:
-        cmd: cargo test -p tokio-executor --tests --features threadpool
   pool:
     vmImage: ubuntu-16.04
   steps:
diff --git a/ci/patch.toml b/ci/patch.toml
index 6718f231..333c4dff 100644
--- a/ci/patch.toml
+++ b/ci/patch.toml
@@ -2,7 +2,6 @@
 # repository.
 [patch.crates-io]
 tokio = { path = "tokio" }
-tokio-executor = { path = "tokio-executor" }
 tokio-macros = { path = "tokio-macros" }
 tokio-sync = { path = "tokio-sync" }
 tokio-tls = { path = "tokio-tls" }
diff --git a/tests-build/Cargo.toml b/tests-build/Cargo.toml
index fb837d03..36dbc883 100644
--- a/tests-build/Cargo.toml
+++ b/tests-build/Cargo.toml
@@ -6,7 +6,7 @@ edition = "2018"
 publish = false
 
 [features]
-executor-without-current-thread = ["tokio-executor"]
+# executor-without-current-thread = ["tokio-executor"]
 # macros-invalid-input = ["tokio/rt-full"]
 # net-no-features = ["tokio-net"]
 # net-with-tcp = ["tokio-net/tcp"]
@@ -19,7 +19,6 @@ executor-without-current-thread = ["tokio-executor"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-tokio-executor = { path = "../tokio-executor", optional = true }
 # tokio = { path = "../tokio", optional = true, default-features = false }
 
 [dev-dependencies]
diff --git a/tokio-executor/CHANGELOG.md b/tokio-executor/CHANGELOG.md
deleted file mode 100644
index d2cca0ba..00000000
--- a/tokio-executor/CHANGELOG.md
+++ /dev/null
@@ -1,81 +0,0 @@
-# 0.2.0-alpha.6 (September 30, 2019)
-
-- Move to `futures-*-preview 0.3.0-alpha.19`
-- Move to `pin-project 0.4`
-
-# 0.2.0-alpha.5 (September 19, 2019)
-
-### Fix
-- shutdown blocking pool threads when idle (#1562, #1514).
-
-# 0.2.0-alpha.4 (August 29, 2019)
-
-- Track tokio release.
-
-# 0.2.0-alpha.3 (August 28, 2019)
-
-### Changed
-- use `tracing` instead of `log`
-
-### Added
-- thread pool dedicated to blocking operations (#1495).
-- `Executor::spawn_with_handle` (#1492).
-
-# 0.2.0-alpha.2 (August 17, 2019)
-
-### Fixed
-- allow running executor from within blocking clause (#1433).
-
-### Changed
-- Update `futures` dependency to 0.3.0-alpha.18.
-
-### Added
-- Import `current-thread` executor (#1447).
-- Import `threadpool` executor (#1152).
-
-# 0.2.0-alpha.1 (August 8, 2019)
-
-### Changed
-- Switch to `async`, `await`, and `std::future`.
-
-### Removed
-- `Enter::make_permanent` and `Enter::on_exit` (#???)
-
-# 0.1.7 (March 22, 2019)
-
-### Added
-- `TypedExecutor` for spawning futures of a specific type (#993).
-
-# 0.1.6 (January 6, 2019)
-
-* Implement `Unpark` for `Arc<Unpark>` (#802).
-* Switch to crossbeam's Parker / Unparker (#528).
-
-# 0.1.5 (September 26, 2018)
-
-* Implement `futures::Executor` for `DefaultExecutor` (#563).
-* Add `Enter::block_on(future)` (#646)
-
-# 0.1.4 (August 23, 2018)
-
-* Implement `std::error::Error` for error types (#511).
-
-# 0.1.3 (August 6, 2018)
-
-* Implement `Executor` for `Box<E: Executor>` (#420).
-* Improve `EnterError` debug message (#410).
-* Implement `status`, `Send`, and `Sync` for `DefaultExecutor` (#463, #472).
-* Fix race in `ParkThread` (#507).
-* Handle recursive calls into `DefaultExecutor` (#473).
-
-# 0.1.2 (March 30, 2018)
-
-* Implement `Unpark` for `Box<Unpark>`.
-
-# 0.1.1 (March 22, 2018)
-
-* Optionally support futures 0.2.
-
-# 0.1.0 (March 09, 2018)
-
-* Initial release
diff --git a/tokio-executor/Cargo.toml b/tokio-executor/Cargo.toml
deleted file mode 100644
index d1bd6a18..00000000
--- a/tokio-executor/Cargo.toml
+++ /dev/null
@@ -1,52 +0,0 @@
-[package]
-name = "tokio-executor"
-# When releasing to crates.io:
-# - Remove path dependencies
-# - Update html_root_url.
-# - Update doc url
-#   - Cargo.toml
-# - Update CHANGELOG.md.
-# - Create "v0.2.x" git tag.
-version = "0.2.0-alpha.6"
-edition = "2018"
-documentation = "https://docs.rs/tokio-executor/0.2.0-alpha.6/tokio_executor"
-repository = "https://github.com/tokio-rs/tokio"
-homepage = "https://github.com/tokio-rs/tokio"
-license = "MIT"
-authors = ["Tokio Contributors <team@tokio.rs>"]
-description = """
-Future execution primitives
-"""
-keywords = ["futures", "tokio"]
-categories = ["concurrency", "asynchronous"]
-
-[features]
-blocking = ["lazy_static"]
-current-thread = ["crossbeam-channel"]
-thread-pool = ["num_cpus"]
-
-[dependencies]
-futures-util-preview = { version = "=0.3.0-alpha.19", features = ["channel"] }
-tokio-sync = { version = "=0.2.0-alpha.6", path = "../tokio-sync" }
-
-# current-thread dependencies
-crossbeam-channel = { version = "0.3.8", optional = true }
-
-# threadpool dependencies
-num_cpus = { version = "1.2", optional = true }
-
-# blocking
-futures-core-preview = { version = "=0.3.0-alpha.19", optional = true }
-lazy_static = { version = "1", optional = true }
-
-[dev-dependenc