openpgp, buffered-reader: Make compression an optional feature.

  - This helps to reduce the trusted computing base if compression is
    not needed.

  - This makes it easier to fuzz Sequoia, previously the fuzzer was
    doing a great job creating compression bombs that triggered the
    fuzzers timeout.

  - Currently, the cargo workspace feature does not propagate
    --no-default-features, but it is possible to depend on the openpgp
    crate with `default-features = false`.

  - Unfortunately, a lot of test cases include compressed packages.
    This change conditionally disables these tests.

4 files changed, 140 insertions, 118 deletions

diff --git a/buffered-reader/Cargo.toml b/buffered-reader/Cargo.toml
index 68f4c60d..1702ac97 100644
--- a/buffered-reader/Cargo.toml
+++ b/buffered-reader/Cargo.toml
@@ -4,5 +4,13 @@ version = "0.1.0"
 authors = ["Neal H. Walfield <neal@gnu.org>"]
 
 [dependencies]
-bzip2 = "0.3.2"
-flate2 = "1.0.1"
+bzip2 = { version = "0.3.2", optional = true }
+flate2 = { version = "1.0.1", optional = true }
+
+[features]
+default = ["compression"]
+
+# The compression algorithms.
+compression = ["compression-deflate", "compression-bzip2"]
+compression-deflate = ["flate2"]
+compression-bzip2 = ["bzip2"]
diff --git a/buffered-reader/src/decompress_bzip2.rs b/buffered-reader/src/decompress_bzip2.rs
new file mode 100644
index 00000000..41fba37a
--- /dev/null
+++ b/buffered-reader/src/decompress_bzip2.rs
@@ -0,0 +1,118 @@
+use std::io;
+use std::fmt;
+
+use bzip2::read::BzDecoder;
+
+use super::*;
+
+
+pub struct BufferedReaderBzip<R: BufferedReader<C>, C> {
+    reader: BufferedReaderGeneric<BzDecoder<R>, C>,
+}
+
+impl <R: BufferedReader<()>> BufferedReaderBzip<R, ()> {
+    /// Instantiate a new bzip decompression reader.  `reader` is
+    /// the source to wrap.
+    pub fn new(reader: R) -> Self {
+        Self::with_cookie(reader, ())
+    }
+}
+
+impl <R: BufferedReader<C>, C> BufferedReaderBzip<R, C> {
+    /// Like `new()`, but sets a cookie, which can be retrieved using
+    /// the `cookie_ref` and `cookie_mut` methods, and set using
+    /// the `cookie_set` method.
+    pub fn with_cookie(reader: R, cookie: C) -> Self {
+        BufferedReaderBzip {
+            reader: BufferedReaderGeneric::with_cookie(
+                BzDecoder::new(reader), None, cookie),
+        }
+    }
+}
+
+impl<R: BufferedReader<C>, C> io::Read for BufferedReaderBzip<R, C> {
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
+        self.reader.read(buf)
+    }
+}
+
+impl <R: BufferedReader<C>, C> fmt::Debug for BufferedReaderBzip<R, C> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("BufferedReaderBzip")
+            .field("reader", &self.get_ref().unwrap())
+            .finish()
+    }
+}
+
+impl<R: BufferedReader<C>, C> BufferedReader<C> for BufferedReaderBzip<R, C> {
+    fn buffer(&self) -> &[u8] {
+        return self.reader.buffer();
+    }
+
+    fn data(&mut self, amount: usize) -> Result<&[u8], io::Error> {
+        return self.reader.data(amount);
+    }
+
+    fn data_hard(&mut self, amount: usize) -> Result<&[u8], io::Error> {
+        return self.reader.data_hard(amount);
+    }
+
+    fn data_eof(&mut self) -> Result<&[u8], io::Error> {
+        return self.reader.data_eof();
+    }
+
+    fn consume(&mut self, amount: usize) -> &[u8] {
+        return self.reader.consume(amount);
+    }
+
+    fn data_consume(&mut self, amount: usize)
+                    -> Result<&[u8], io::Error> {
+        return self.reader.data_consume(amount);
+    }
+
+    fn data_consume_hard(&mut self, amount: usize) -> Result<&[u8], io::Error> {
+        return self.reader.data_consume_hard(amount);
+    }
+
+    fn read_be_u16(&mut self) -> Result<u16, io::Error> {
+        return self.reader.read_be_u16();
+    }
+
+    fn read_be_u32(&mut self) -> Result<u32, io::Error> {
+        return self.reader.read_be_u32();
+    }
+
+    fn steal(&mut self, amount: usize) -> Result<Vec<u8>, io::Error> {
+        return self.reader.steal(amount);
+    }
+
+    fn steal_eof(&mut self) -> Result<Vec<u8>, io::Error> {
+        return self.reader.steal_eof();
+    }
+
+    fn get_mut(&mut self) -> Option<&mut BufferedReader<C>> {
+        Some(self.reader.reader.get_mut())
+    }
+
+    fn get_ref(&self) -> Option<&BufferedReader<C>> {
+        Some(self.reader.reader.get_ref())
+    }
+
+    fn into_inner<'b>(self: Box<Self>)
+            -> Option<Box<BufferedReader<C> + 'b>> where Self: 'b {
+        // Strip the outer box.
+        Some(Box::new(self.reader.reader.into_inner()))
+    }
+
+    fn cookie_set(&mut self, cookie: C) -> C {
+        self.reader.cookie_set(cookie)
+    }
+
+    fn cookie_ref(&self) -> &C {
+        self.reader.cookie_ref()
+    }
+
+    fn cookie_mut(&mut self) -> &mut C {
+        self.reader.cookie_mut()
+    }
+}
diff --git a/buffered-reader/src/decompress.rs b/buffered-reader/src/decompress_deflate.rs
index 376edd06..c46b9eea 100644
--- a/buffered-reader/src/decompress.rs
+++ b/buffered-reader/src/decompress_deflate.rs
@@ -3,7 +3,6 @@ use std::fmt;
 
 use flate2::read::DeflateDecoder;
 use flate2::read::ZlibDecoder;
-use bzip2::read::BzDecoder;
 
 use super::*;
 
@@ -230,117 +229,6 @@ impl<R: BufferedReader<C>, C> BufferedReader<C>
         self.reader.cookie_mut()
     }
 }
-
-pub struct BufferedReaderBzip<R: BufferedReader<C>, C> {
-    reader: BufferedReaderGeneric<BzDecoder<R>, C>,
-}
-
-impl <R: BufferedReader<()>> BufferedReaderBzip<R, ()> {
-    /// Instantiate a new bzip decompression reader.  `reader` is
-    /// the source to wrap.
-    pub fn new(reader: R) -> Self {
-        Self::with_cookie(reader, ())
-    }
-}
-
-impl <R: BufferedReader<C>, C> BufferedReaderBzip<R, C> {
-    /// Like `new()`, but sets a cookie, which can be retrieved using
-    /// the `cookie_ref` and `cookie_mut` methods, and set using
-    /// the `cookie_set` method.
-    pub fn with_cookie(reader: R, cookie: C) -> Self {
-        BufferedReaderBzip {
-            reader: BufferedReaderGeneric::with_cookie(
-                BzDecoder::new(reader), None, cookie),
-        }
-    }
-}
-
-impl<R: BufferedReader<C>, C> io::Read for BufferedReaderBzip<R, C> {
-    fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> {
-        self.reader.read(buf)
-    }
-}
-
-impl <R: BufferedReader<C>, C> fmt::Debug for BufferedReaderBzip<R, C> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("BufferedReaderBzip")
-            .field("reader", &self.get_ref().unwrap())
-            .finish()
-    }
-}
-
-impl<R: BufferedReader<C>, C> BufferedReader<C> for BufferedReaderBzip<R, C> {
-    fn buffer(&self) -> &[u8] {
-        return self.reader.buffer();
-    }
-
-    fn data(&mut self, amount: usize) -> Result<&[u8], io::Error> {
-        return self.reader.data(amount);
-    }
-
-    fn data_hard(&mut self, amount: usize) -> Result<&[u8], io::Error> {
-        return self.reader.data_hard(amount);
-    }
-
-    fn data_eof(&mut self) -> Result<&[u8], io::Error> {
-        return self.reader.data_eof();
-    }
-
-    fn consume(&mut self, amount: usize) -> &[u8] {
-        return self.reader.consume(amount);
-    }
-
-    fn data_consume(&mut self, amount: usize)
-                    -> Result<&[u8], io::Error> {
-        return self.reader.data_consume(amount);
-    }
-
-    fn data_consume_hard(&mut self, amount: usize) -> Result<&[u8], io::Error> {
-        return self.reader.data_consume_hard(amount);
-    }
-
-    fn read_be_u16(&mut self) -> Result<u16, io::Error> {
-        return self.reader.read_be_u16();
-    }
-
-    fn read_be_u32(&mut self) -> Result<u32, io::Error> {
-        return self.reader.read_be_u32();
-    }
-
-    fn steal(&mut self, amount: usize) -> Result<Vec<u8>, io::Error> {
-        return self.reader.steal(amount);
-    }
-
-    fn steal_eof(&mut self) -> Result<Vec<u8>, io::Error> {
-        return self.reader.steal_eof();
-    }
-
-    fn get_mut(&mut self) -> Option<&mut BufferedReader<C>> {
-        Some(self.reader.reader.get_mut())
-    }
-
-    fn get_ref(&self) -> Option<&BufferedReader<C>> {
-        Some(self.reader.reader.get_ref())
-    }
-
-    fn into_inner<'b>(self: Box<Self>)
-            -> Option<Box<BufferedReader<C> + 'b>> where Self: 'b {
-        // Strip the outer box.
-        Some(Box::new(self.reader.reader.into_inner()))
-    }
-
-    fn cookie_set(&mut self, cookie: C) -> C {
-        self.reader.cookie_set(cookie)
-    }
-
-    fn cookie_ref(&self) -> &C {
-        self.reader.cookie_ref()
-    }
-
-    fn cookie_mut(&mut self) -> &mut C {
-        self.reader.cookie_mut()
-    }
-}
 
 #[cfg(test)]
 mod test {
diff --git a/buffered-reader/src/lib.rs b/buffered-reader/src/lib.rs
index ab19fa37..9619e0de 100644
--- a/buffered-reader/src/lib.rs
+++ b/buffered-reader/src/lib.rs
@@ -1,6 +1,8 @@
 //! An improved `BufRead` interface.
 
+#[cfg(feature = "compression-deflate")]
 extern crate flate2;
+#[cfg(feature = "compression-bzip2")]
 extern crate bzip2;
 
 use std::io;
@@ -13,16 +15,22 @@ mod memory;
 mod limitor;
 mod dup;
 mod eof;
-mod decompress;
+#[cfg(feature = "compression-deflate")]
+mod decompress_deflate;
+#[cfg(feature = "compression-bzip2")]
+mod decompress_bzip2;
 
 pub use self::generic::BufferedReaderGeneric;
 pub use self::memory::BufferedReaderMemory;
 pub use self::limitor::BufferedReaderLimitor;
 pub use self::dup::BufferedReaderDup;
 pub use self::eof::BufferedReaderEOF;
-pub use self::decompress::BufferedReaderDeflate;
-pub use self::decompress::BufferedReaderZlib;
-pub use self::decompress::BufferedReaderBzip;
+#[cfg(feature = "compression-deflate")]
+pub use self::decompress_deflate::BufferedReaderDeflate;
+#[cfg(feature = "compression-deflate")]
+pub use self::decompress_deflate::BufferedReaderZlib;
+#[cfg(feature = "compression-bzip2")]
+pub use self::decompress_bzip2::BufferedReaderBzip;
 
 // The default buffer size.
 const DEFAULT_BUF_SIZE: usize = 8 * 1024;