From b1e51b91d2996e6657d1c149a38224aad1f84547 Mon Sep 17 00:00:00 2001
From: John <j@842.be>
Date: Sun, 27 Apr 2025 21:30:25 +1200
Subject: [PATCH] Add fancy hashing

---
 CMakeLists.txt                       |  6 ++
 install_prerequisites.sh             |  2 +-
 src/utils/hash.cpp                   | 99 ++++++++++++++++++++++++++++
 src/utils/hash.hpp                   | 16 +++++
 templates/example-nginx/uninstall.sh |  2 +-
 5 files changed, 123 insertions(+), 2 deletions(-)
 create mode 100644 src/utils/hash.cpp
 create mode 100644 src/utils/hash.hpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index fcadf8a..9fb0d93 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,8 +27,12 @@ configure_file(
     @ONLY
 )
 
+# Set CMAKE_MODULE_PATH to include our custom find modules
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
+
 # Find required packages
 find_package(TBB REQUIRED)
+find_package(xxHash REQUIRED)
 
 # Auto-detect source files
 file(GLOB_RECURSE SOURCES "src/*.cpp")
@@ -41,11 +45,13 @@ add_executable(dropshell ${SOURCES})
 target_include_directories(dropshell PRIVATE 
     src
     ${CMAKE_CURRENT_BINARY_DIR}/src
+    ${xxHash_INCLUDE_DIRS}
 )
 
 # Link libraries
 target_link_libraries(dropshell PRIVATE
     TBB::tbb
+    ${xxHash_LIBRARIES}
 )
 
 # Install targets
diff --git a/install_prerequisites.sh b/install_prerequisites.sh
index 9ca91c5..1b2e478 100755
--- a/install_prerequisites.sh
+++ b/install_prerequisites.sh
@@ -41,7 +41,7 @@ print_status "Detected OS: $OS $VER"
 case $OS in
     "Ubuntu"|"Debian GNU/Linux")
         # Common packages for both Ubuntu and Debian
-        PACKAGES="cmake make g++ devscripts debhelper libtbb-dev"
+        PACKAGES="cmake make g++ devscripts debhelper libtbb-dev libxxhash-dev"
         ;;
     *)
         print_error "Unsupported distribution: $OS"
diff --git a/src/utils/hash.cpp b/src/utils/hash.cpp
new file mode 100644
index 0000000..234a7c0
--- /dev/null
+++ b/src/utils/hash.cpp
@@ -0,0 +1,99 @@
+#include "hash.hpp"
+#include <fstream>
+#include <filesystem>
+#include <iostream>
+
+namespace dropshell {
+
+XXH64_hash_t hash_file(const std::string &path) {
+    // Create hash state
+    XXH64_state_t* const state = XXH64_createState();
+    if (state == nullptr) {
+        std::cerr << "Failed to create hash state" << std::endl;
+        return 0;
+    }
+
+    // Initialize state with seed 0
+    if (XXH64_reset(state, 0) == XXH_ERROR) {
+        std::cerr << "Failed to reset hash state" << std::endl;
+        XXH64_freeState(state);
+        return 0;
+    }
+
+    // Open file
+    std::ifstream file(path, std::ios::binary);
+    if (!file.is_open()) {
+        std::cerr << "Failed to open file: " << path << std::endl;
+        XXH64_freeState(state);
+        return 0;
+    }
+
+    // Read file in chunks and update hash
+    const size_t buffer_size = 4096;
+    char buffer[buffer_size];
+    while (file.read(buffer, buffer_size)) {
+        if (XXH64_update(state, buffer, file.gcount()) == XXH_ERROR) {
+            std::cerr << "Failed to update hash" << std::endl;
+            XXH64_freeState(state);
+            return 0;
+        }
+    }
+
+    // Handle any remaining bytes
+    if (file.gcount() > 0) {
+        if (XXH64_update(state, buffer, file.gcount()) == XXH_ERROR) {
+            std::cerr << "Failed to update hash" << std::endl;
+            XXH64_freeState(state);
+            return 0;
+        }
+    }
+
+    // Get final hash
+    XXH64_hash_t hash = XXH64_digest(state);
+    XXH64_freeState(state);
+    return hash;
+}
+
+XXH64_hash_t hash_directory_recursive(const std::string &path) {
+    // Create hash state
+    XXH64_state_t* const state = XXH64_createState();
+    if (state == nullptr) {
+        std::cerr << "Failed to create hash state" << std::endl;
+        return 0;
+    }
+
+    // Initialize state with seed 0
+    if (XXH64_reset(state, 0) == XXH_ERROR) {
+        std::cerr << "Failed to reset hash state" << std::endl;
+        XXH64_freeState(state);
+        return 0;
+    }
+
+    try {
+        // Iterate through all files in directory recursively
+        for (const auto& entry : std::filesystem::recursive_directory_iterator(path)) {
+            if (entry.is_regular_file()) {
+                // Get file hash
+                XXH64_hash_t file_hash = hash_file(entry.path().string());
+                
+                // Update directory hash with file hash
+                if (XXH64_update(state, &file_hash, sizeof(file_hash)) == XXH_ERROR) {
+                    std::cerr << "Failed to update hash" << std::endl;
+                    XXH64_freeState(state);
+                    return 0;
+                }
+            }
+        }
+    } catch (const std::filesystem::filesystem_error& e) {
+        std::cerr << "Filesystem error: " << e.what() << std::endl;
+        XXH64_freeState(state);
+        return 0;
+    }
+
+    // Get final hash
+    XXH64_hash_t hash = XXH64_digest(state);
+    XXH64_freeState(state);
+    return hash;
+}
+
+} // namespace dropshell
diff --git a/src/utils/hash.hpp b/src/utils/hash.hpp
new file mode 100644
index 0000000..de96840
--- /dev/null
+++ b/src/utils/hash.hpp
@@ -0,0 +1,16 @@
+#ifndef HASH_HPP
+#define HASH_HPP
+
+#include <xxhash.h>
+#include <string>
+
+namespace dropshell {
+
+    XXH64_hash_t hash_file(const std::string &path);
+
+    XXH64_hash_t hash_directory_recursive(const std::string &path);
+
+} // namespace dropshell
+
+
+#endif
\ No newline at end of file
diff --git a/templates/example-nginx/uninstall.sh b/templates/example-nginx/uninstall.sh
index 58afb63..185a91b 100644
--- a/templates/example-nginx/uninstall.sh
+++ b/templates/example-nginx/uninstall.sh
@@ -16,4 +16,4 @@ _is_container_exists && die "Couldn't remove existing container"
 docker rmi "$IMAGE_REGISTRY/$IMAGE_REPO:$IMAGE_TAG" || echo "Failed to remove image $IMAGE_REGISTRY/$IMAGE_REPO:$IMAGE_TAG"
 
 echo "Uninstallation of ${CONTAINER_NAME} complete."
-echo "Leaving local data folder ${LOCAL_DATA_FOLDER} in place."
+echo "Local data folder ${LOCAL_DATA_FOLDER} still in place."