Don't consume readers with FixedLengthReader

We can't always assume that we're done reading after using a
FixedLengthReader. In some cases, we may need to read a set of
length-prefixed objects one at a time, and we'd like to do so without
incurring an additional allocation by reading a number of bytes first to
then deserialize them.

diff --git a/lightning/src/crypto/streams.rs b/lightning/src/crypto/streams.rs
index 14921a386126e1c5c18f36d7f32c0410390dd0aa..e8217b8d9d3999a1feb647fbb1e9d5456bed5ea8 100644 (file)
--- a/lightning/src/crypto/streams.rs
+++ b/lightning/src/crypto/streams.rs
@@ -151,7 +151,7 @@ mod tests {
                                let writeable_len = $obj.serialized_length() as u64 + 16;
                                let write_adapter = ChaChaPolyWriteAdapter::new(rho, &$obj);
                                let encrypted_writeable_bytes = write_adapter.encode();
-                               let encrypted_writeable = &encrypted_writeable_bytes[..];
+                               let encrypted_writeable = &mut &encrypted_writeable_bytes[..];
 
                                // Now deserialize the object back and make sure it matches the original.
                                let mut rd = FixedLengthReader::new(encrypted_writeable, writeable_len);

diff --git a/lightning/src/events/mod.rs b/lightning/src/events/mod.rs
index d4fa90c6a73e0c6ab200292d6764f1a6e5443f3a..f849dcc2fc24a29dd9dc9e5acfa1a06ca03c39a1 100644 (file)
--- a/lightning/src/events/mod.rs
+++ b/lightning/src/events/mod.rs
@@ -1294,7 +1294,7 @@ impl MaybeReadable for Event {
                        // Note that we do not write a length-prefixed TLV for FundingGenerationReady events.
                        0u8 => Ok(None),
                        1u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut payment_hash = PaymentHash([0; 32]);
                                        let mut payment_preimage = None;
                                        let mut payment_secret = None;
@@ -1342,7 +1342,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        2u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut payment_preimage = PaymentPreimage([0; 32]);
                                        let mut payment_hash = None;
                                        let mut payment_id = None;
@@ -1366,7 +1366,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        3u8 => {
-                               let f = || {
+                               let mut f = || {
                                        #[cfg(test)]
                                        let error_code = Readable::read(reader)?;
                                        #[cfg(test)]
@@ -1409,7 +1409,7 @@ impl MaybeReadable for Event {
                        },
                        4u8 => Ok(None),
                        5u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut outputs = WithoutLength(Vec::new());
                                        let mut channel_id: Option<ChannelId> = None;
                                        read_tlv_fields!(reader, {
@@ -1445,7 +1445,7 @@ impl MaybeReadable for Event {
                                }))
                        },
                        7u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut prev_channel_id = None;
                                        let mut next_channel_id = None;
                                        let mut prev_user_channel_id = None;
@@ -1473,7 +1473,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        9u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut channel_id = ChannelId::new_zero();
                                        let mut reason = UpgradableRequired(None);
                                        let mut user_channel_id_low_opt: Option<u64> = None;
@@ -1503,7 +1503,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        11u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut channel_id = ChannelId::new_zero();
                                        let mut transaction = Transaction{ version: 2, lock_time: LockTime::ZERO, input: Vec::new(), output: Vec::new() };
                                        read_tlv_fields!(reader, {
@@ -1515,7 +1515,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        13u8 => {
-                               let f = || {
+                               let mut f = || {
                                        _init_and_read_len_prefixed_tlv_fields!(reader, {
                                                (0, payment_id, required),
                                                (2, payment_hash, option),
@@ -1531,7 +1531,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        15u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut payment_hash = PaymentHash([0; 32]);
                                        let mut payment_id = PaymentId([0; 32]);
                                        let mut reason = None;
@@ -1553,7 +1553,7 @@ impl MaybeReadable for Event {
                                Ok(None)
                        },
                        19u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut payment_hash = PaymentHash([0; 32]);
                                        let mut purpose = UpgradableRequired(None);
                                        let mut amount_msat = 0;
@@ -1580,7 +1580,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        21u8 => {
-                               let f = || {
+                               let mut f = || {
                                        _init_and_read_len_prefixed_tlv_fields!(reader, {
                                                (0, payment_id, required),
                                                (2, payment_hash, required),
@@ -1596,7 +1596,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        23u8 => {
-                               let f = || {
+                               let mut f = || {
                                        _init_and_read_len_prefixed_tlv_fields!(reader, {
                                                (0, payment_id, required),
                                                (2, payment_hash, required),
@@ -1614,7 +1614,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        25u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut prev_channel_id = ChannelId::new_zero();
                                        let mut failed_next_destination_opt = UpgradableRequired(None);
                                        read_tlv_fields!(reader, {
@@ -1630,7 +1630,7 @@ impl MaybeReadable for Event {
                        },
                        27u8 => Ok(None),
                        29u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut channel_id = ChannelId::new_zero();
                                        let mut user_channel_id: u128 = 0;
                                        let mut counterparty_node_id = RequiredWrapper(None);
@@ -1652,7 +1652,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        31u8 => {
-                               let f = || {
+                               let mut f = || {
                                        let mut channel_id = ChannelId::new_zero();
                                        let mut user_channel_id: u128 = 0;
                                        let mut former_temporary_channel_id = None;
@@ -1680,7 +1680,7 @@ impl MaybeReadable for Event {
                                f()
                        },
                        33u8 => {
-                               let f = || {
+                               let mut f = || {
                                        _init_and_read_len_prefixed_tlv_fields!(reader, {
                                                (0, payment_id, required),
                                        });

diff --git a/lightning/src/util/ser.rs b/lightning/src/util/ser.rs
index 0611e6ffb385b66459f93d3cee1fc46ec1f46223..f333fa2bac27f5182e4122a5321e684fc83a08ab 100644 (file)
--- a/lightning/src/util/ser.rs
+++ b/lightning/src/util/ser.rs
@@ -108,14 +108,14 @@ impl Writer for LengthCalculatingWriter {
 /// forward to ensure we always consume exactly the fixed length specified.
 ///
 /// This is not exported to bindings users as manual TLV building is not currently supported in bindings
-pub struct FixedLengthReader<R: Read> {
-       read: R,
+pub struct FixedLengthReader<'a, R: Read> {
+       read: &'a mut R,
        bytes_read: u64,
        total_bytes: u64,
 }
-impl<R: Read> FixedLengthReader<R> {
+impl<'a, R: Read> FixedLengthReader<'a, R> {
        /// Returns a new [`FixedLengthReader`].
-       pub fn new(read: R, total_bytes: u64) -> Self {
+       pub fn new(read: &'a mut R, total_bytes: u64) -> Self {
                Self { read, bytes_read: 0, total_bytes }
        }
 
@@ -136,7 +136,7 @@ impl<R: Read> FixedLengthReader<R> {
                }
        }
 }
-impl<R: Read> Read for FixedLengthReader<R> {
+impl<'a, R: Read> Read for FixedLengthReader<'a, R> {
        #[inline]
        fn read(&mut self, dest: &mut [u8]) -> Result<usize, io::Error> {
                if self.total_bytes == self.bytes_read {
@@ -154,7 +154,7 @@ impl<R: Read> Read for FixedLengthReader<R> {
        }
 }
 
-impl<R: Read> LengthRead for FixedLengthReader<R> {
+impl<'a, R: Read> LengthRead for FixedLengthReader<'a, R> {
        #[inline]
        fn total_bytes(&self) -> u64 {
                self.total_bytes

diff --git a/lightning/src/util/ser_macros.rs b/lightning/src/util/ser_macros.rs
index 84d9f7a180bb301a1c18a136530a04ce75589a9e..dce160a7c5eecd5325ef30b9a219f8a067bf5fce 100644 (file)
--- a/lightning/src/util/ser_macros.rs
+++ b/lightning/src/util/ser_macros.rs
@@ -1033,7 +1033,7 @@ macro_rules! impl_writeable_tlv_based_enum {
                                        $($variant_id => {
                                                // Because read_tlv_fields creates a labeled loop, we cannot call it twice
                                                // in the same function body. Instead, we define a closure and call it.
-                                               let f = || {
+                                               let mut f = || {
                                                        $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });
@@ -1087,7 +1087,7 @@ macro_rules! impl_writeable_tlv_based_enum_upgradable {
                                        $($variant_id => {
                                                // Because read_tlv_fields creates a labeled loop, we cannot call it twice
                                                // in the same function body. Instead, we define a closure and call it.
-                                               let f = || {
+                                               let mut f = || {
                                                        $crate::_init_and_read_len_prefixed_tlv_fields!(reader, {
                                                                $(($type, $field, $fieldty)),*
                                                        });