pcap: refactor to take Write, rename struct

src/pcap.rs

@@ -1,9 +1,8 @@
 use crate::gsmtap::GsmtapMessage;
 use crate::diag::Timestamp;
 
-use std::fs::File;
+use std::io::Write;
 use std::borrow::Cow;
-use std::path::Path;
 use chrono::prelude::*;
 use deku::prelude::*;
 use pcap_file::pcapng::blocks::enhanced_packet::EnhancedPacketBlock;
@@ -13,7 +12,7 @@ use pcap_file::PcapError;
 use thiserror::Error;
 
 #[derive(Error, Debug)]
-pub enum PcapFileError {
+pub enum GsmtapPcapError {
     #[error("IO error: {0}")]
     Io(#[from] std::io::Error),
     #[error("Pcap error: {0}")]
@@ -22,8 +21,8 @@ pub enum PcapFileError {
     Deku(#[from] DekuError),
 }
 
-pub struct PcapFile {
-    writer: PcapNgWriter<File>,
+pub struct GsmtapPcapWriter<T> where T: Write {
+    writer: PcapNgWriter<T>,
     ip_id: u16,
 }
 
@@ -55,17 +54,13 @@ struct UdpHeader {
     checksum: u16,
 }
 
-impl PcapFile {
-    pub fn new<P>(path: P) -> Result<Self, PcapFileError> where P: AsRef<Path> {
-        let file = std::fs::File::options()
-            .create(true)
-            .write(true)
-            .open(path)?;
-        let writer = PcapNgWriter::new(file)?;
-        Ok(PcapFile { writer, ip_id: 0 })
+impl<T> GsmtapPcapWriter<T> where T: Write {
+    pub fn new(writer: T) -> Result<Self, GsmtapPcapError> {
+        let writer = PcapNgWriter::new(writer)?;
+        Ok(GsmtapPcapWriter { writer, ip_id: 0 })
     }
 
-    pub fn write_iface_header(&mut self) -> Result<(), PcapFileError> {
+    pub fn write_iface_header(&mut self) -> Result<(), GsmtapPcapError> {
         let interface = InterfaceDescriptionBlock {
             linktype: pcap_file::DataLink::IPV4,
             snaplen: 0xffff,
@@ -75,7 +70,7 @@ impl PcapFile {
         Ok(())
     }
 
-    pub fn write_gsmtap_message(&mut self, msg: GsmtapMessage, timestamp: Timestamp) -> Result<(), PcapFileError> {
+    pub fn write_gsmtap_message(&mut self, msg: GsmtapMessage, timestamp: Timestamp) -> Result<(), GsmtapPcapError> {
         let time_since_epoch = timestamp.to_datetime().signed_duration_since(DateTime::UNIX_EPOCH);
         let secs_since_epoch = time_since_epoch.num_seconds() as u64;
         let nsecs_since_epoch = time_since_epoch.num_nanoseconds().unwrap_or(0) as u32;