Live can

Cargo.lock

@@ -356,7 +356,7 @@ checksum = "0ae92a5119aa49cdbcf6b9f893fe4e1d98b04ccbf82ee0584ad948a44a734dea"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -488,7 +488,7 @@ checksum = "3b43422f69d8ff38f95f1b2bb76517c91589a924d1559a0e935d7c8ce0274c11"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -523,7 +523,7 @@ checksum = "9035ad2d096bed7955a320ee7e2230574d28fd3c3a0f186cbea1ff3c7eed5dbb"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -588,7 +588,7 @@ dependencies = [
  "derive_utils",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -673,7 +673,7 @@ dependencies = [
  "regex",
  "rustc-hash 2.1.2",
  "shlex",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -839,7 +839,7 @@ checksum = "f9abbd1bc6865053c427f7198e6af43bfdedc55ab791faed4fbd361d789575ff"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -1092,7 +1092,7 @@ checksum = "9b5dc851b7ea80cc4f69aa28632385ffd3e0f88014d53db3f2e5a781896ca783"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -1314,7 +1314,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "rustc_version",
- "syn",
+ "syn 2.0.117",
  "unicode-xid",
 ]
 
@@ -1326,7 +1326,7 @@ checksum = "362f47930db19fe7735f527e6595e4900316b893ebf6d48ad3d31be928d57dd6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -1365,7 +1365,7 @@ checksum = "97369cbbc041bc366949bc74d34658d6cda5621039731c6310521892a3a20ae0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -1610,6 +1610,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "embedded-can"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e9d2e857f87ac832df68fa498d18ddc679175cf3d2e4aa893988e5601baf9438"
+dependencies = [
+ "nb",
+]
+
 [[package]]
 name = "encoding_rs"
 version = "0.8.35"
@@ -1643,7 +1652,7 @@ checksum = "67c78a4d8fdf9953a5c9d458f9efe940fd97a0cab0941c075a813ac594733827"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -1654,7 +1663,7 @@ checksum = "2f9ed6b3789237c8a0c1c505af1c7eb2c560df6186f01b098c3a1064ea532f38"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -1703,7 +1712,7 @@ checksum = "44f23cf4b44bfce11a86ace86f8a73ffdec849c9fd00a386a53d278bd9e81fb3"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -1946,7 +1955,7 @@ checksum = "1a5c6c585bc94aaf2c7b51dd4c2ba22680844aba4c687be581871a6f518c5742"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -2039,7 +2048,7 @@ checksum = "e835b70203e41293343137df5c0664546da5745f82ec9b84d40be8336958447b"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -2415,7 +2424,7 @@ dependencies = [
  "i-slint-renderer-software",
  "input",
  "memmap2",
- "nix",
+ "nix 0.30.1",
  "xkbcommon",
 ]
 
@@ -2584,7 +2593,7 @@ checksum = "7931356d5238281e6be994ec15241fb2d9e66359776d53b4bd6b2fdd9c257c6e"
 dependencies = [
  "quote",
  "serde_json",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -2945,7 +2954,7 @@ checksum = "c34819042dc3d3971c46c2190835914dfbe0c3c13f61449b2997f4e9722dfa60"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -3010,7 +3019,7 @@ dependencies = [
  "quote",
  "rustc_version",
  "simd_cesu8",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -3038,7 +3047,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "38c0b942f458fe50cdac086d2f946512305e5631e720728f2a61aabcd47a6264"
 dependencies = [
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -3281,7 +3290,7 @@ dependencies = [
  "quote",
  "regex-automata",
  "regex-syntax",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -3519,6 +3528,12 @@ version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "308d96db8debc727c3fd9744aac51751243420e46edf401010908da7f8d5e57c"
 
+[[package]]
+name = "nb"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d5439c4ad607c3c23abf66de8c8bf57ba8adcd1f129e699851a6e43935d339d"
+
 [[package]]
 name = "ndk"
 version = "0.9.0"
@@ -3549,12 +3564,50 @@ dependencies = [
  "jni-sys 0.3.1",
 ]
 
+[[package]]
+name = "neli"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93062a0dce6da2517ea35f301dfc88184ce18d3601ec786a727a87bf535deca9"
+dependencies = [
+ "byteorder",
+ "libc",
+ "log",
+ "neli-proc-macros",
+]
+
+[[package]]
+name = "neli-proc-macros"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c8034b7fbb6f9455b2a96c19e6edf8dc9fc34c70449938d8ee3b4df363f61fe"
+dependencies = [
+ "either",
+ "proc-macro2",
+ "quote",
+ "serde",
+ "syn 1.0.109",
+]
+
 [[package]]
 name = "new_debug_unreachable"
 version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "650eef8c711430f1a879fdd01d4745a7deea475becfb90269c06775983bbf086"
 
+[[package]]
+name = "nix"
+version = "0.29.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
+dependencies = [
+ "bitflags 2.11.1",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+ "memoffset",
+]
+
 [[package]]
 name = "nix"
 version = "0.30.1"
@@ -3625,7 +3678,7 @@ checksum = "ed3955f1a9c7c0c15e092f9c887db08b1fc683305fdf6eb6684f22555355e202"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -3677,7 +3730,7 @@ dependencies = [
  "proc-macro-crate",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -4246,7 +4299,7 @@ dependencies = [
  "pest_meta",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -4290,7 +4343,7 @@ dependencies = [
  "phf_shared",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -4325,7 +4378,7 @@ checksum = "c96395f0a926bc13b1c17622aaddda1ecb55d49c8f1bf9777e4d877800a43f8b"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -4486,7 +4539,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "479ca8adacdd7ce8f1fb39ce9ecccbfe93a3f1344b3d0d97f20bc0196208f62b"
 dependencies = [
  "proc-macro2",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -4523,7 +4576,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4488a4a36b9a4ba6b9334a32a39971f77c1436ec82c38707bce707699cc3bbcb"
 dependencies = [
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -5050,7 +5103,7 @@ checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -5074,7 +5127,7 @@ checksum = "175ee3e80ae9982737ca543e96133087cbd9a485eecc3bc4de9c1a37b47ea59c"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -5367,7 +5420,36 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
+]
+
+[[package]]
+name = "socket2"
+version = "0.5.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e22376abed350d73dd1cd119b57ffccad95b4e585a7cda43e286245ce23c0678"
+dependencies = [
+ "libc",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "socketcan"
+version = "3.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f5e63effc7e77256358f700e5fb0160238501022fec00b75d5da03e9e385d932"
+dependencies = [
+ "bitflags 2.11.1",
+ "embedded-can",
+ "hex",
+ "itertools 0.13.0",
+ "libc",
+ "log",
+ "nb",
+ "neli",
+ "nix 0.29.0",
+ "socket2",
+ "thiserror 2.0.18",
 ]
 
 [[package]]
@@ -5467,7 +5549,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -5512,6 +5594,7 @@ dependencies = [
  "fuzzy-matcher",
  "libsvld",
  "rfd",
+ "socketcan",
 ]
 
 [[package]]
@@ -5525,6 +5608,17 @@ dependencies = [
  "zeno",
 ]
 
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.117"
@@ -5544,7 +5638,7 @@ checksum = "728a70f3dbaf5bab7f0c4b1ac8d7ae5ea60a4b5549c8a5914361c99147a709d2"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -5642,7 +5736,7 @@ checksum = "4fee6c4efc90059e10f81e6d42c60a18f76588c3d74cb83a0b242a2b6c7504c1"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -5653,7 +5747,7 @@ checksum = "ebc4ee7f67670e9b64d05fa4253e753e016c6c95ff35b89b7941d6b856dec1d5"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -5850,7 +5944,7 @@ checksum = "7490cfa5ec963746568740651ac6781f701c9c5ea257c58e057f3ba8cf69e8da"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -6138,7 +6232,7 @@ checksum = "482a37f9777480673d3a99c80ac2edc69f92382230440946855fa27ebc47cba6"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -6211,7 +6305,7 @@ dependencies = [
  "bumpalo",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
  "wasm-bindgen-shared",
 ]
 
@@ -6893,7 +6987,7 @@ checksum = "053e2e040ab57b9dc951b72c264860db7eb3b0200ba345b4e4c3b14f67855ddf"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -6904,7 +6998,7 @@ checksum = "3f316c4a2570ba26bbec722032c4099d8c8bc095efccdc15688708623367e358"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -7327,7 +7421,7 @@ dependencies = [
  "heck",
  "indexmap",
  "prettyplease",
- "syn",
+ "syn 2.0.117",
  "wasm-metadata",
  "wit-bindgen-core",
  "wit-component",
@@ -7343,7 +7437,7 @@ dependencies = [
  "prettyplease",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
  "wit-bindgen-core",
  "wit-bindgen-rust",
 ]
@@ -7555,7 +7649,7 @@ checksum = "de844c262c8848816172cef550288e7dc6c7b7814b4ee56b3e1553f275f1858e"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
  "synstructure",
 ]
 
@@ -7612,7 +7706,7 @@ checksum = "10da05367f3a7b7553c8cdf8fa91aee6b64afebe32b51c95177957efc47ca3a0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
  "zbus-lockstep",
  "zbus_xml",
  "zvariant",
@@ -7627,7 +7721,7 @@ dependencies = [
  "proc-macro-crate",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
  "zbus_names",
  "zvariant",
  "zvariant_utils",
@@ -7679,7 +7773,7 @@ checksum = "70e3cd084b1788766f53af483dd21f93881ff30d7320490ec3ef7526d203bad4"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -7699,7 +7793,7 @@ checksum = "11532158c46691caf0f2593ea8358fed6bbf68a0315e80aae9bd41fbade684a1"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
  "synstructure",
 ]
 
@@ -7735,7 +7829,7 @@ checksum = "625dc425cab0dca6dc3c3319506e6593dcb08a9f387ea3b284dbd52a92c40555"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
 ]
 
 [[package]]
@@ -7791,7 +7885,7 @@ dependencies = [
  "proc-macro-crate",
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.117",
  "zvariant_utils",
 ]
 
@@ -7804,6 +7898,6 @@ dependencies = [
  "proc-macro2",
  "quote",
  "serde",
- "syn",
+ "syn 2.0.117",
  "winnow 1.0.3",
 ]

libsvld/src/lib.rs

@@ -30,16 +30,11 @@ struct FrameOutput {
     error_frames: Vec<ErrorFrame>,
 }
 
-fn frame_worker(
+/// Build the LD metadata for a single CAN id from the DBC, applying the
-    mmap: &[u8],
+/// project's `ld_*`/`Frequency` attribute defaults. Returns `None` when the
-    dbc: &Dbc,
+/// id is not described by the DBC (an "unknown" id). Shared by the ASC decode
-) -> FrameOutput {
+/// path and the live-CAN path so both produce identical metadata.
-    let mut channel_data = HashMap::<CanId, Vec<CanFrame>>::new();
+pub fn build_message_metadata(dbc: &Dbc, id: CanId) -> Option<MessageMetadata> {
-    let mut metadatas = HashMap::<CanId, MessageMetadata>::new();
-
-    let mut unknown_ids = HashSet::<CanId>::new();
-    let mut error_frames = Vec::<ErrorFrame>::new();
-
     let get_default = |name: &str| match dbc
         .attribute_defaults
         .iter()
@@ -56,57 +51,66 @@ fn frame_worker(
     let default_scale = get_default("ld_scale");
     let default_decimal_places = get_default("ld_decimal_places");
 
-    let mut add_metadata = |id| {
+    let msg = dbc.messages.iter().find(|x| x.id.raw() == id)?;
-        let msg = match dbc.messages.iter().find(|x| x.id.raw() == id) {
+    let signals = &msg.signals;
-            Some(msg) => msg,
+    let mut signals_meta = Vec::<SignalMetadata>::new();
-            None => {
+    for signal in signals {
-                unknown_ids.insert(id);
+        let decimal_places = dbc
-                return;
+            .attribute_values_signal
-            }
-        };
-        let signals = &msg.signals;
-        let mut signals_meta = Vec::<SignalMetadata>::new();
-        for signal in signals {
-            let decimal_places = dbc
-                .attribute_values_signal
-                .iter()
-                .find(|x| {
-                    x.message_id.raw() == id
-                        && x.signal_name == signal.name
-                        && x.name == "ld_decimal_places"
-                })
-                .map_or(default_decimal_places, |x| match x.value {
-                    can_dbc::AttributeValue::Uint(val) => val,
-                    _ => panic!("Bad ld_decimal_places value type, expected Uint."),
-                });
-
-            signals_meta.push(SignalMetadata {
-                shift: default_shift as u16,
-                scale: default_scale as u16,
-                decimal_places: decimal_places as u16,
-                name: signal.name.clone(),
-                unit: signal.unit.clone(),
-                signal: signal.clone(),
-            });
-        }
-
-        let frequency = dbc
-            .attribute_values_message
             .iter()
-            .find(|x| x.message_id.raw() == id && x.name == "Frequency")
+            .find(|x| {
-            .map_or(default_freqency, |x| match x.value {
+                x.message_id.raw() == id
+                    && x.signal_name == signal.name
+                    && x.name == "ld_decimal_places"
+            })
+            .map_or(default_decimal_places, |x| match x.value {
                 can_dbc::AttributeValue::Uint(val) => val,
-                _ => panic!("Bad Frequency value type, expected Uint."),
+                _ => panic!("Bad ld_decimal_places value type, expected Uint."),
             });
 
-        metadatas.insert(
+        signals_meta.push(SignalMetadata {
-            id,
+            shift: default_shift as u16,
-            MessageMetadata {
+            scale: default_scale as u16,
-                id,
+            decimal_places: decimal_places as u16,
-                frequency: frequency as u16,
+            name: signal.name.clone(),
-                signals: signals_meta,
+            unit: signal.unit.clone(),
-            },
+            signal: signal.clone(),
-        );
+        });
+    }
+
+    let frequency = dbc
+        .attribute_values_message
+        .iter()
+        .find(|x| x.message_id.raw() == id && x.name == "Frequency")
+        .map_or(default_freqency, |x| match x.value {
+            can_dbc::AttributeValue::Uint(val) => val,
+            _ => panic!("Bad Frequency value type, expected Uint."),
+        });
+
+    Some(MessageMetadata {
+        id,
+        frequency: frequency as u16,
+        signals: signals_meta,
+    })
+}
+
+fn frame_worker(
+    mmap: &[u8],
+    dbc: &Dbc,
+) -> FrameOutput {
+    let mut channel_data = HashMap::<CanId, Vec<CanFrame>>::new();
+    let mut metadatas = HashMap::<CanId, MessageMetadata>::new();
+
+    let mut unknown_ids = HashSet::<CanId>::new();
+    let mut error_frames = Vec::<ErrorFrame>::new();
+
+    let mut add_metadata = |id| match build_message_metadata(dbc, id) {
+        Some(meta) => {
+            metadatas.insert(id, meta);
+        }
+        None => {
+            unknown_ids.insert(id);
+        }
     };
 
     // Caller has aligned the chunk to line boundaries, so we always start at
@@ -171,6 +175,51 @@ pub struct DecodeResult {
     pub info: DecodeProcessInfo,
 }
 
+impl DecodeResult {
+    /// An empty result suitable for incrementally accumulating live CAN
+    /// frames via [`DecodeResult::push_live`]. The `info` fields that only
+    /// make sense for the file-based decode are zeroed.
+    pub fn empty() -> Self {
+        DecodeResult {
+            data: HashMap::new(),
+            metadata: HashMap::new(),
+            info: DecodeProcessInfo {
+                unknown_ids: HashSet::new(),
+                error_frames: Vec::new(),
+                date: chrono::DateTime::from_timestamp(0, 0).unwrap().naive_utc(),
+                thread_count: 0,
+                page_size: 0,
+                pages_per_chunk: 0,
+                chunk_size: 0,
+            },
+        }
+    }
+
+    /// Append a single live frame, lazily resolving its metadata from the DBC
+    /// the first time an id is seen. Frames are expected to arrive in
+    /// non-decreasing timestamp order (as they do off a live bus), so no
+    /// re-sorting is performed — `compute_signal` consumes them in order.
+    pub fn push_live(&mut self, dbc: &Dbc, frame: CanFrame) {
+        match self.data.get_mut(&frame.can_id) {
+            Some(vec) => vec.push(frame),
+            None => {
+                let id = frame.can_id;
+                self.data.insert(id, vec![frame]);
+                if !self.metadata.contains_key(&id) {
+                    match build_message_metadata(dbc, id) {
+                        Some(meta) => {
+                            self.metadata.insert(id, meta);
+                        }
+                        None => {
+                            self.info.unknown_ids.insert(id);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
 pub fn decode(dbc: &Dbc,
               asc_path: &Path) -> DecodeResult {
     let thread_count = std::thread::available_parallelism().unwrap().get();

svldplotter/Cargo.toml

@@ -21,3 +21,4 @@ egui_plot = "0.35"
 egui_ltreeview = "0.7"
 fuzzy-matcher = "0.3"
 rfd = "0.17"
+socketcan = "3.6.1"

svldplotter/src/main.rs

@@ -1,3 +1,4 @@
+mod can_live;
 mod plot;
 mod plot_list;
 mod signal;
@@ -13,7 +14,7 @@ use std::{
 
 use can_dbc::Dbc;
 use eframe::egui;
-use libsvld::DecodeResult;
+use libsvld::{can_frame::CanFrame, DecodeResult};
 
 use crate::plot::show_plot_panel;
 use crate::plot_list::{
@@ -30,13 +31,36 @@ fn main() {
         native_options,
         Box::new(|cc| {
             let mut app = MyEguiApp::default();
-            // Optional CLI quick-load: `svldplotter [DBC [ASC]]`. Both args
+            // Optional CLI quick-load. Positional args are an optional DBC and
-            // are optional and intended for dev iteration.
+            // ASC, intended for dev iteration:
+            //   svldplotter [DBC [ASC]]
+            // Passing `--can <iface>` (e.g. `svldplotter car.dbc --can can0`)
+            // switches to live mode: instead of reading an ASC file the
+            // plotter streams frames straight off the CAN bus and plots them
+            // in real time, using the DBC for signal metadata.
             let args: Vec<String> = std::env::args().collect();
-            if let Some(dbc) = args.get(1) {
+            let mut positional: Vec<String> = Vec::new();
+            let mut can_iface: Option<String> = None;
+            let mut i = 1;
+            while i < args.len() {
+                match args[i].as_str() {
+                    "--can" | "-c" => {
+                        can_iface = args.get(i + 1).cloned();
+                        i += 2;
+                    }
+                    other => {
+                        positional.push(other.to_string());
+                        i += 1;
+                    }
+                }
+            }
+            if let Some(dbc) = positional.first() {
                 app.load_dbc(PathBuf::from(dbc));
             }
-            if let Some(asc) = args.get(2) {
+            if let Some(iface) = can_iface {
+                // Live CAN takes precedence over any ASC argument.
+                app.start_can_live(&iface, &cc.egui_ctx);
+            } else if let Some(asc) = positional.get(1) {
                 app.asc_paths.push(PathBuf::from(asc));
                 app.set_active_asc(app.asc_paths.len() - 1, Some(&cc.egui_ctx));
             }
@@ -74,6 +98,13 @@ struct MyEguiApp {
     next_plot_id: u64,
     cursor_x: Option<f64>,
     left_tab: LeftTab,
+    /// Live CAN stream receiver, present only in `--can` mode.
+    live_rx: Option<Receiver<CanFrame>>,
+    /// Growing decode result fed by the live CAN stream.
+    live_data: Option<DecodeResult>,
+    /// Latest data x-extent from the previous frame, used to detect whether
+    /// the live view is pinned to the right edge for auto-scroll.
+    live_prev_max: Option<f64>,
 }
 
 impl MyEguiApp {
@@ -182,15 +213,95 @@ impl MyEguiApp {
         self.data = Some(data);
     }
 
-    fn handle_dbc_toggles(&mut self, toggles: Vec<u64>) {
+    /// Enter live CAN mode: open `iface` and start streaming frames into a
-        let Some(data) = self.data.clone() else {
+    /// fresh, growing `DecodeResult`. Requires a DBC to already be loaded so
+    /// incoming frames can be resolved to signals.
+    fn start_can_live(&mut self, iface: &str, ctx: &egui::Context) {
+        if self.dbc.is_none() {
+            eprintln!("Cannot start live CAN: no DBC loaded.");
+            return;
+        }
+        match can_live::spawn_reader(iface) {
+            Ok(rx) => {
+                self.live_rx = Some(rx);
+                self.live_data = Some(DecodeResult::empty());
+                // Clear any file-based state so the two sources don't mix.
+                self.active_asc = None;
+                self.data = None;
+                self.tree.clear();
+                ctx.request_repaint();
+            }
+            Err(e) => {
+                eprintln!("Failed to open CAN interface '{iface}': {e}");
+            }
+        }
+    }
+
+    /// Drain any frames received from the live CAN stream, fold them into the
+    /// live `DecodeResult`, and re-resolve the tree and plotted signals so the
+    /// UI reflects the latest data. A repaint is always requested while live
+    /// so polling continues even when no frame arrived this tick.
+    fn poll_live(&mut self, ctx: &egui::Context) {
+        if self.live_rx.is_none() {
+            return;
+        }
+        // Keep the UI ticking so we keep polling the stream.
+        ctx.request_repaint();
+
+        let Some(dbc) = self.dbc.clone() else {
             return;
         };
+
+        // Collect first so the receiver borrow is released before we mutate
+        // `self.live_data` below.
+        let frames: Vec<CanFrame> = self
+            .live_rx
+            .as_ref()
+            .map(|rx| rx.try_iter().collect())
+            .unwrap_or_default();
+        if frames.is_empty() {
+            return;
+        }
+
+        let Some(live) = self.live_data.as_mut() else {
+            return;
+        };
+        for frame in frames {
+            live.push_live(&dbc, frame);
+        }
+
+        // Re-resolve tree and plots against the updated live data. These touch
+        // disjoint fields of `self`, so the borrows don't conflict.
+        let data = self.live_data.as_ref().unwrap();
+        self.tree = build_tree(&dbc, data);
+        for plot in &mut self.plots {
+            for sig in &mut plot.signals {
+                if let Some((msg_id, sig_idx)) = decode_signal_node_id(sig.id) {
+                    if let Some(new_sig) = compute_signal(data, msg_id, sig_idx, sig.id) {
+                        *sig = new_sig;
+                    }
+                }
+            }
+        }
+    }
+
+    fn handle_dbc_toggles(&mut self, toggles: Vec<u64>) {
         for id in toggles {
             if contains_signal(&self.plots, id) {
                 remove_signal(&mut self.plots, id);
             } else if let Some((msg_id, sig_idx)) = decode_signal_node_id(id) {
-                if let Some(sig) = compute_signal(&data, msg_id, sig_idx, id) {
+                // Pull from the live stream when in `--can` mode, otherwise the
+                // decoded ASC. Accessed as disjoint fields so the immutable
+                // data borrow doesn't clash with the `self.plots` mutation.
+                let data = if self.live_data.is_some() {
+                    self.live_data.as_ref()
+                } else {
+                    self.data.as_deref()
+                };
+                let Some(data) = data else {
+                    continue;
+                };
+                if let Some(sig) = compute_signal(data, msg_id, sig_idx, id) {
                     add_signal_auto(&mut self.plots, &mut self.next_plot_id, sig);
                 }
             }
@@ -267,6 +378,7 @@ impl eframe::App for MyEguiApp {
         self.poll_pending();
 
         let ctx = ui.ctx().clone();
+        self.poll_live(&ctx);
         egui::Panel::left(egui::Id::new("LeftPanel"))
             .resizable(true)
             .show_inside(ui, |ui| {
@@ -317,7 +429,13 @@ impl eframe::App for MyEguiApp {
                     }
                 }
             });
-        show_plot_panel(ui, &self.plots, &mut self.cursor_x);
+        show_plot_panel(
+            ui,
+            &self.plots,
+            &mut self.cursor_x,
+            self.live_rx.is_some(),
+            &mut self.live_prev_max,
+        );
 
         if let Some(job) = self.pending.as_ref() {
             let name = job

svldplotter/src/plot.rs

@@ -65,7 +65,20 @@ fn line_label(sig: &PlottedSignal, cursor_x: Option<f64>) -> String {
 /// Clamp the visible x-range to [0, x_max]. Preserves the current zoom
 /// width when possible; if the zoomed-out width exceeds the data range,
 /// just snaps to the full range.
-fn clamp_x_bounds(plot_ui: &mut egui_plot::PlotUi, x_max: f64) {
+///
+/// In live mode, if the view's right edge was pinned to the latest sample
+/// (`prev_max`, the data extent from the previous frame), the window is
+/// scrolled right to keep the right edge at the new `x_max` so the plot
+/// auto-follows incoming data. Panning away from the edge disengages this.
+fn clamp_x_bounds(
+    plot_ui: &mut egui_plot::PlotUi,
+    x_max: f64,
+    live: bool,
+    prev_max: Option<f64>,
+) {
+    if !x_max.is_finite() {
+        return;
+    }
     let bounds = plot_ui.plot_bounds();
     let lo = bounds.min();
     let hi = bounds.max();
@@ -73,6 +86,19 @@ fn clamp_x_bounds(plot_ui: &mut egui_plot::PlotUi, x_max: f64) {
     let mut new_hi_x = hi[0];
     let width = new_hi_x - new_lo_x;
 
+    if live && width < x_max {
+        // Pinned when the right edge sits at (or past) the previous extent.
+        // A tiny epsilon absorbs float error from last frame's snap.
+        let pinned = match prev_max {
+            Some(p) => new_hi_x >= p - width * 1e-3,
+            None => true,
+        };
+        if pinned {
+            new_hi_x = x_max;
+            new_lo_x = x_max - width;
+        }
+    }
+
     if width >= x_max {
         new_lo_x = 0.0;
         new_hi_x = x_max;
@@ -99,6 +125,8 @@ pub fn show_plot_panel(
     ui: &mut egui::Ui,
     plots: &[PlotGroup],
     cursor_x: &mut Option<f64>,
+    live: bool,
+    prev_max: &mut Option<f64>,
 ) {
     egui::CentralPanel::default().show_inside(ui, |ui| {
         if plots.is_empty() {
@@ -109,6 +137,12 @@ pub fn show_plot_panel(
         }
 
         let (full_min, full_max) = full_x_range(plots);
+        // Snapshot the previous frame's extent for the auto-follow decision,
+        // then record this frame's for the next one.
+        let follow_prev_max = *prev_max;
+        if full_max.is_finite() {
+            *prev_max = Some(full_max);
+        }
         let link_group = ui.id().with("plot-link");
         let plot_count = plots.len();
         let plot_height =
@@ -145,7 +179,7 @@ pub fn show_plot_panel(
                 ]);
 
             let response = plot.show(ui, |plot_ui| {
-                clamp_x_bounds(plot_ui, full_max);
+                clamp_x_bounds(plot_ui, full_max, live, follow_prev_max);
                 if plot_group.signals.is_empty() {
                     plot_ui.line(
                         Line::new(