Protobuf 2.4.0, generate all proto files every time, but only write when changed, supporting poor souls with crlf line ending conversion.

Drop Regex dependency, just parse using simple string methods.

Protobuf 2.4.0, generate all proto files every time, but only write when changed, supporting poor souls with crlf line ending conversion.

Cargo.lock

@@ -956,6 +956,7 @@ name = "librespot-protocol"
 version = "0.1.0"
 dependencies = [
  "protobuf 2.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "protobuf-codegen 2.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "protobuf-codegen-pure 2.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 

protocol/Cargo.toml

@@ -9,3 +9,4 @@ protobuf = "2.8.*"
 
 [build-dependencies]
 protobuf-codegen-pure = "2.8.*"
+protobuf-codegen = "*"

protocol/build.rs

@@ -1,93 +1,54 @@
-extern crate protobuf_codegen_pure;
+extern crate protobuf_codegen; // Does the business
-use protobuf_codegen_pure::Customize;
+extern crate protobuf_codegen_pure; // Helper function
-use std::fs::File;
-use std::io::prelude::*;
 
-mod files;
+use std::path::Path;
+use std::fs::{read_to_string, write};
+
+use protobuf_codegen_pure::Customize;
+use protobuf_codegen_pure::parse_and_typecheck;
 
 fn main() {
-    let mut changed = false;
+    let customizations = Customize { ..Default::default() };
-    let mut file = File::open("files.rs").unwrap();
+
-    let mut f_str = String::new();
+    let lib_str = read_to_string("src/lib.rs").unwrap();
-    file.read_to_string(&mut f_str).unwrap();
+
-    drop(file);
+    // Iterate over the desired module names.
-    for &(path, expected_checksum) in files::FILES {
+    for line in lib_str.lines() {
-        let actual = cksum_file(path).unwrap();
+        if !line.starts_with("pub mod ") {
-        if expected_checksum != actual {
+            continue;
-            protobuf_codegen_pure::run(protobuf_codegen_pure::Args {
+        }
-                out_dir: "src",
+        let len = line.len();
-                input: &[path],
+        let name = &line[8..len-1]; // Remove keywords and semi-colon
-                includes: &["proto"],
+
-                customize: Customize { ..Default::default() },
+        // Build the paths to relevant files.
-            }).expect("protoc");
+        let src = &format!("proto/{}.proto", name);
-            let new_checksum = cksum_file(path).unwrap();
+        let dest = &format!("src/{}.rs", name);
-            f_str = f_str.replace(&expected_checksum.to_string(), &new_checksum.to_string());
+
-            changed = true;
+        // Get the contents of the existing generated file.
+        let mut existing = "".to_string();
+        if Path::new(dest).exists() {
+            // Removing CRLF line endings if present.
+            existing = read_to_string(dest).unwrap().replace("\r\n", "\n");
+        }
+
+        println!("Regenerating {} from {}", dest, src);
+
+        // Parse the proto files as the protobuf-codegen-pure crate does.
+        let p = parse_and_typecheck(&["proto"], &[src]).expect("protoc");
+        // But generate them with the protobuf-codegen crate directly.
+        // Then we can keep the result in-memory.
+        let result = protobuf_codegen::gen(
+            &p.file_descriptors,
+            &p.relative_paths,
+            &customizations,
+        );
+        // Protoc result as a byte array.
+        let new = &result.first().unwrap().content;
+        // Convert to utf8 to compare with existing.
+        let new = std::str::from_utf8(&new).unwrap();
+        // Save newly generated file if changed.
+        if new != existing {
+            write(dest, &new).unwrap();
         }
     }
-    if changed {
-        // Write new checksums to file
-        let mut file = File::create("files.rs").unwrap();
-        file.write_all(f_str.as_bytes()).unwrap();
-    }
 }
-
-fn cksum_file<T: AsRef<std::path::Path>>(path: T) -> std::io::Result<u32> {
-    let mut file = File::open(path)?;
-    let mut contents = Vec::new();
-    file.read_to_end(&mut contents)?;
-
-    Ok(cksum(&contents))
-}
-
-fn cksum<T: AsRef<[u8]>>(data: T) -> u32 {
-    let data = data.as_ref();
-
-    let mut value = 0u32;
-    for x in data {
-        value = (value << 8) ^ CRC_LOOKUP_ARRAY[(*x as u32 ^ (value >> 24)) as usize];
-    }
-
-    let mut n = data.len();
-    while n != 0 {
-        value = (value << 8) ^ CRC_LOOKUP_ARRAY[((n & 0xFF) as u32 ^ (value >> 24)) as usize];
-        n >>= 8;
-    }
-
-    !value
-}
-
-static CRC_LOOKUP_ARRAY: &'static [u32] = &[
-    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
-    0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
-    0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
-    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
-    0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
-    0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
-    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
-    0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
-    0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
-    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
-    0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
-    0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
-    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
-    0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
-    0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
-    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
-    0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
-    0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
-    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
-    0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
-    0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
-    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
-    0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
-    0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
-    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
-    0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
-    0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
-    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
-    0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
-    0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
-    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
-    0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
-];

protocol/files.rs

@@ -1,10 +0,0 @@
-// Autogenerated by build.rs
-
-pub const FILES: &'static [(&'static str, u32)] = &[
-    ("proto/authentication.proto", 2098196376),
-    ("proto/keyexchange.proto", 451735664),
-    ("proto/mercury.proto", 709993906),
-    ("proto/metadata.proto", 2474472423),
-    ("proto/pubsub.proto", 2686584829),
-    ("proto/spirc.proto", 1587493382),
-];

protocol/src/lib.rs

@@ -1,6 +1,6 @@
-// Autogenerated by build.sh
-
 extern crate protobuf;
+// This file is parsed by build.rs
+// Each included module will be compiled from the matching .proto definition.
 pub mod authentication;
 pub mod keyexchange;
 pub mod mercury;