Merge pull request #293 from willstott101/protobuf-codegen-pure

Simplify librespot-protocol build caching.

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;
-use protobuf_codegen_pure::Customize;
-use std::fs::File;
-use std::io::prelude::*;
+extern crate protobuf_codegen; // Does the business
+extern crate protobuf_codegen_pure; // Helper function
 
-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 mut file = File::open("files.rs").unwrap();
-    let mut f_str = String::new();
-    file.read_to_string(&mut f_str).unwrap();
-    drop(file);
-    for &(path, expected_checksum) in files::FILES {
-        let actual = cksum_file(path).unwrap();
-        if expected_checksum != actual {
-            protobuf_codegen_pure::run(protobuf_codegen_pure::Args {
-                out_dir: "src",
-                input: &[path],
-                includes: &["proto"],
-                customize: Customize { ..Default::default() },
-            }).expect("protoc");
-            let new_checksum = cksum_file(path).unwrap();
-            f_str = f_str.replace(&expected_checksum.to_string(), &new_checksum.to_string());
-            changed = true;
+    let customizations = Customize { ..Default::default() };
+
+    let lib_str = read_to_string("src/lib.rs").unwrap();
+
+    // Iterate over the desired module names.
+    for line in lib_str.lines() {
+        if !line.starts_with("pub mod ") {
+            continue;
         }
+        let len = line.len();
+        let name = &line[8..len-1]; // Remove keywords and semi-colon
+
+        // Build the paths to relevant files.
+        let src = &format!("proto/{}.proto", name);
+        let dest = &format!("src/{}.rs", name);
+
+        // 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;