[vcpkg] Enable storing archives across filesystems

toolsrc/include/vcpkg/base/files.h

@@ -37,6 +37,10 @@ namespace vcpkg::Files
         virtual void write_contents(const fs::path& file_path, const std::string& data, std::error_code& ec) = 0;
         virtual void rename(const fs::path& oldpath, const fs::path& newpath) = 0;
         virtual void rename(const fs::path& oldpath, const fs::path& newpath, std::error_code& ec) = 0;
+        virtual void rename_or_copy(const fs::path& oldpath,
+                                    const fs::path& newpath,
+                                    StringLiteral temp_suffix,
+                                    std::error_code& ec) = 0;
         virtual bool remove(const fs::path& path) = 0;
         virtual bool remove(const fs::path& path, std::error_code& ec) = 0;
         virtual std::uintmax_t remove_all(const fs::path& path, std::error_code& ec) = 0;

toolsrc/src/vcpkg/base/files.cpp

@@ -4,6 +4,14 @@
 #include <vcpkg/base/system.h>
 #include <vcpkg/base/util.h>
 
+#if defined(__linux__)
+#include <fcntl.h>
+#include <sys/sendfile.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#endif
+
 namespace vcpkg::Files
 {
     static const std::regex FILESYSTEM_INVALID_CHARACTERS_REGEX = std::regex(R"([\/:*?"<>|])");
@@ -117,6 +125,42 @@ namespace vcpkg::Files
         {
             fs::stdfs::rename(oldpath, newpath);
         }
+        virtual void rename_or_copy(const fs::path& oldpath,
+                                    const fs::path& newpath,
+                                    StringLiteral temp_suffix,
+                                    std::error_code& ec) override
+        {
+            this->rename(oldpath, newpath, ec);
+#if defined(__linux__)
+            if (ec)
+            {
+                auto dst = newpath;
+                dst.replace_filename(dst.filename() + temp_suffix.c_str());
+
+                int i_fd = open(oldpath.c_str(), O_RDONLY);
+                if (i_fd == -1) return;
+
+                int o_fd = creat(dst.c_str(), 0664);
+                if (o_fd == -1)
+                {
+                    close(i_fd);
+                    return;
+                }
+
+                off_t bytes = 0;
+                struct stat info = {0};
+                fstat(i_fd, &info);
+                auto written_bytes = sendfile(o_fd, i_fd, &bytes, info.st_size);
+                close(i_fd);
+                close(o_fd);
+                if (written_bytes == -1) return;
+
+                this->rename(dst, newpath, ec);
+                if (ec) return;
+                this->remove(oldpath, ec);
+            }
+#endif
+        }
         virtual bool remove(const fs::path& path) override { return fs::stdfs::remove(path); }
         virtual bool remove(const fs::path& path, std::error_code& ec) override { return fs::stdfs::remove(path, ec); }
         virtual std::uintmax_t remove_all(const fs::path& path, std::error_code& ec) override

toolsrc/src/vcpkg/build.cpp

@@ -646,10 +646,14 @@ namespace vcpkg::Build
                 compress_archive(paths, spec, tmp_archive_path);
 
                 fs.create_directories(archive_path.parent_path(), ec);
-                fs.rename(tmp_archive_path, archive_path, ec);
+                fs.rename_or_copy(tmp_archive_path, archive_path, ".tmp", ec);
                 if (ec)
-                    System::println(
+                {
-                        System::Color::warning, "Failed to store binary cache: %s", archive_path.u8string());
+                    System::println(System::Color::warning,
+                                    "Failed to store binary cache %s: %s",
+                                    archive_path.u8string(),
+                                    ec.message());
+                }
                 else
                     System::println("Stored binary cache: %s", archive_path.u8string());
             }