protos: Update to protobuf 2.3

This matches the version already used by crostini_client.

The newer protobuf version depends on the tempfile crate rather than
tempdir, the latter being now deprecated. So I replaced our immitation
tempdir crate with one that matches the API of tempfile instead. As a
reminder, we use this crate as a patch to avoid pulling in all of the
rand crate and its many dependencies.

TEST=cargo check --features plugin
CQ-DEPEND=CL:1553971

Change-Id: I28eed3ceadb1013f015400b4c582aaf8dc89eee1
Reviewed-on: https://chromium-review.googlesource.com/1562924
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: David Tolnay <dtolnay@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

2 files changed, 85 insertions, 0 deletions

diff --git a/tempfile/Cargo.toml b/tempfile/Cargo.toml
new file mode 100644
index 0000000..b12e976
--- /dev/null
+++ b/tempfile/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "tempfile"
+version = "3.0.7"
+authors = ["The Chromium OS Authors"]
+edition = "2018"
+
+[dependencies]
+rand_ish = { path = "../rand_ish" }
diff --git a/tempfile/src/lib.rs b/tempfile/src/lib.rs
new file mode 100644
index 0000000..c04f0f7
--- /dev/null
+++ b/tempfile/src/lib.rs
@@ -0,0 +1,77 @@
+// Copyright 2019 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//! Simplified tempfile which doesn't depend on the `rand` crate, instead using
+//! /dev/urandom as a source of entropy
+
+extern crate rand_ish;
+
+use rand_ish::urandom_str;
+use std::env;
+use std::fs;
+use std::io::{Error, ErrorKind, Result};
+use std::path::{Path, PathBuf};
+
+pub struct Builder {
+    prefix: String,
+}
+
+impl Builder {
+    pub fn new() -> Self {
+        Builder {
+            prefix: ".tmp".to_owned(),
+        }
+    }
+
+    /// Set a custom filename prefix.
+    ///
+    /// Default: `.tmp`
+    pub fn prefix(&mut self, prefix: &str) -> &mut Self {
+        self.prefix = prefix.to_owned();
+        self
+    }
+
+    /// Tries to make a tempdir inside of `env::temp_dir()` with a specified
+    /// prefix. The directory and it's content is destroyed when TempDir is
+    /// dropped.
+    /// If the directory can not be created, `Err` is returned.
+    pub fn tempdir(&self) -> Result<TempDir> {
+        for _ in 0..NUM_RETRIES {
+            let suffix = urandom_str(12)?;
+            let path = env::temp_dir().join(format!("{}.{}", self.prefix, suffix));
+
+            match fs::create_dir(&path) {
+                Ok(_) => return Ok(TempDir { path }),
+                Err(ref e) if e.kind() == ErrorKind::AlreadyExists => {}
+                Err(e) => return Err(e),
+            }
+        }
+
+        Err(Error::new(
+            ErrorKind::AlreadyExists,
+            "too many tempdirs exist",
+        ))
+    }
+}
+
+pub struct TempDir {
+    path: PathBuf,
+}
+
+const NUM_RETRIES: u32 = 4;
+
+impl TempDir {
+    /// Accesses the tempdir's [`Path`].
+    ///
+    /// [`Path`]: http://doc.rust-lang.org/std/path/struct.Path.html
+    pub fn path(&self) -> &Path {
+        self.path.as_ref()
+    }
+}
+
+impl Drop for TempDir {
+    fn drop(&mut self) {
+        let _ = fs::remove_dir_all(&self.path);
+    }
+}