Restore Windows support with MSVC (#108)

* switch to MSVC, fixes to support it

* fix linking errors

* document how to patch zcash source

* update hash due to nightly breakage; don't use deprecated bindgen function

* update patch with str4d's upstream suggestion

---------

Co-authored-by: Alfredo Garcia <oxarbitrage@gmail.com>

.github/workflows/ci.yml

@@ -74,7 +74,7 @@ jobs:
     strategy:
       matrix:
         # "windows-latest" was removed; see https://github.com/ZcashFoundation/zcash_script/issues/38
-        os: [ubuntu-latest, macOS-latest]
+        os: [ubuntu-latest, macOS-latest, windows-latest]
     steps:
       - uses: actions/checkout@v4
         with:
@@ -85,16 +85,10 @@ jobs:
       # - name: install LLVM on Mac
       #   if: matrix.os == 'macOS-latest'
       #   run: brew install llvm
-      - name: install LLVM on Windows
-        if: matrix.os == 'windows-latest'
-        run: |
-          choco install llvm -y
-          echo "C:\Program Files\LLVM\bin" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
-          echo "LIBCLANG_PATH=C:\Program Files\LLVM\bin" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
       - uses: actions-rs/toolchain@v1
         if: matrix.os == 'windows-latest'
         with:
-          target: x86_64-pc-windows-gnu
+          target: x86_64-pc-windows-msvc
           toolchain: stable
           profile: minimal
           override: true
@@ -108,7 +102,7 @@ jobs:
         if: matrix.os == 'windows-latest'
         with:
           command: test
-          args: --target x86_64-pc-windows-gnu
+          args: --target x86_64-pc-windows-msvc
       - uses: actions-rs/cargo@v1
         if: matrix.os != 'windows-latest'
         with:

README.md

@@ -47,13 +47,19 @@ work correctly. Since we don't allow those in our repository, we start over
 every time, basically using it as a glorified `git clone`. This issue is being
 tracked in https://github.com/ZcashFoundation/zcash_script/issues/35.
 
+We also need to patch the zcash source to enable Windows compatibility. This
+is done by applying a patch file as described below. If the patch application
+fails, check the patch file for reference on what needs to be changed (and
+update the patch file).
+
 If you need to update the zcash source, run:
 
 ```console
 git rm -r depend/zcash
 (commit changes)
 git subtree add -P depend/zcash https://github.com/zcash/zcash.git <ref> --squash
 git rm depend/zcash/Cargo.toml
+git apply zcash.patch
 (commit changes)
 ```
 

build.rs

@@ -32,7 +32,7 @@ fn bindgen_headers() -> Result<()> {
         .header("depend/zcash/src/script/zcash_script.h")
         // Tell cargo to invalidate the built crate whenever any of the
         // included header files changed.
-        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
+        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
         // Finish the builder and generate the bindings.
         .generate()
         .map_err(|_| Error::GenerateBindings)?;
@@ -115,7 +115,7 @@ fn gen_cxxbridge() -> Result<()> {
         fs::create_dir_all(header_path.parent().unwrap()).unwrap();
         fs::write(header_path, output.header).unwrap();
 
-        let src_path = src_out_path.join(format!("{}.c", filename));
+        let src_path = src_out_path.join(format!("{}.cpp", filename));
         // Create output dir if does not exist (since `filename` can have a subdir)
         fs::create_dir_all(src_path.parent().unwrap()).unwrap();
         fs::write(src_path, output.implementation).unwrap();
@@ -203,10 +203,12 @@ fn main() -> Result<()> {
     base_config
         .file("depend/zcash/src/script/zcash_script.cpp")
         .file("depend/zcash/src/util/strencodings.cpp")
+        .file("depend/zcash/src/amount.cpp")
         .file("depend/zcash/src/uint256.cpp")
         .file("depend/zcash/src/pubkey.cpp")
         .file("depend/zcash/src/hash.cpp")
         .file("depend/zcash/src/streams_rust.cpp")
+        .file("depend/zcash/src/zip317.cpp")
         .file("depend/zcash/src/primitives/transaction.cpp")
         .file("depend/zcash/src/crypto/ripemd160.cpp")
         .file("depend/zcash/src/crypto/sha1.cpp")
@@ -217,11 +219,12 @@ fn main() -> Result<()> {
         .file("depend/zcash/src/script/script.cpp")
         .file("depend/zcash/src/script/script_error.cpp")
         .file("depend/zcash/src/support/cleanse.cpp")
+        .file("depend/zcash/src/zcash/cache.cpp")
         // A subset of the files generated by gen_cxxbridge
         // which are required by zcash_script.
-        .file(gen_path.join("src/blake2b.c"))
-        .file(gen_path.join("src/bridge.c"))
-        .file(gen_path.join("src/streams.c"))
+        .file(gen_path.join("src/blake2b.cpp"))
+        .file(gen_path.join("src/bridge.cpp"))
+        .file(gen_path.join("src/streams.cpp"))
         .compile("libzcash_script.a");
 
     Ok(())

depend/zcash/src/zcash/cache.cpp

@@ -3,16 +3,16 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include "zcash/cache.h"
-#include "util/system.h"
+// #include "util/system.h"
 
 namespace libzcash
 {
 std::unique_ptr<BundleValidityCache> NewBundleValidityCache(rust::Str kind, size_t nMaxCacheSize)
 {
     auto cache = std::unique_ptr<BundleValidityCache>(new BundleValidityCache());
     size_t nElems = cache->setup_bytes(nMaxCacheSize);
-    LogPrintf("Using %zu MiB out of %zu requested for %s bundle cache, able to store %zu elements\n",
-              (nElems * sizeof(BundleCacheEntry)) >> 20, nMaxCacheSize >> 20, kind, nElems);
+    // LogPrintf("Using %zu MiB out of %zu requested for %s bundle cache, able to store %zu elements\n",
+    //           (nElems * sizeof(BundleCacheEntry)) >> 20, nMaxCacheSize >> 20, kind, nElems);
     return cache;
 }
 } // namespace libzcash

depend/zcash/src/zcash/cache.h

@@ -31,7 +31,7 @@ class BundleCacheHasher
     {
         static_assert(hash_select < 8, "BundleCacheHasher only has 8 hashes available.");
         uint32_t u;
-        std::memcpy(&u, key.begin() + 4 * hash_select, 4);
+        std::memcpy(&u, key.data() + 4 * hash_select, 4);
         return u;
     }
 };

zcash.patch

@@ -0,0 +1,37 @@
+diff --git a/depend/zcash/src/zcash/cache.cpp b/depend/zcash/src/zcash/cache.cpp
+index c5cd6b173c..1da334b377 100644
+--- a/depend/zcash/src/zcash/cache.cpp
++++ b/depend/zcash/src/zcash/cache.cpp
+@@ -3,7 +3,7 @@
+ // file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+ #include "zcash/cache.h"
+-#include "util/system.h"
++// #include "util/system.h"
+
+ namespace libzcash
+ {
+@@ -11,8 +11,8 @@ std::unique_ptr<BundleValidityCache> NewBundleValidityCache(rust::Str kind, size
+ {
+     auto cache = std::unique_ptr<BundleValidityCache>(new BundleValidityCache());
+     size_t nElems = cache->setup_bytes(nMaxCacheSize);
+-    LogPrintf("Using %zu MiB out of %zu requested for %s bundle cache, able to store %zu elements\n",
+-              (nElems * sizeof(BundleCacheEntry)) >> 20, nMaxCacheSize >> 20, kind, nElems);
++    // LogPrintf("Using %zu MiB out of %zu requested for %s bundle cache, able to store %zu elements\n",
++    //           (nElems * sizeof(BundleCacheEntry)) >> 20, nMaxCacheSize >> 20, kind, nElems);
+     return cache;
+ }
+ } // namespace libzcash
+diff --git a/depend/zcash/src/zcash/cache.h b/depend/zcash/src/zcash/cache.h
+index 9bef1e43b5..283123bec9 100644
+--- a/depend/zcash/src/zcash/cache.h
++++ b/depend/zcash/src/zcash/cache.h
+@@ -31,7 +31,7 @@ public:
+     {
+         static_assert(hash_select < 8, "BundleCacheHasher only has 8 hashes available.");
+         uint32_t u;
+-        std::memcpy(&u, key.begin() + 4 * hash_select, 4);
++        std::memcpy(&u, key.data() + 4 * hash_select, 4);
+         return u;
+     }
+ };