Add libmagic wrapper

Also builds separate static library linuxdeploy_util providing old util
header and new magic wrapper.

CMakeLists.txt

@@ -8,6 +8,8 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(LINUXDEPLOY_VERSION 0.1-alpha-1)
 add_definitions(-DLINUXDEPLOY_VERSION="${LINUXDEPLOY_VERSION}")
 
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/Modules/")
+
 add_subdirectory(lib)
 
 add_subdirectory(src)

cmake/Modules/FindLibMagic.cmake

@@ -0,0 +1,21 @@
+message(STATUS "Searching for libmagic")
+
+find_library(LIBMAGIC_A libmagic.a)
+
+if(NOT LIBMAGIC_A)
+    message(FATAL_ERROR "libmagic.a not found")
+endif()
+
+find_path(LIBMAGIC_MAGIC_H
+    NAMES magic.h
+    HINTS ${CMAKE_INSTALL_PREFIX}
+    PATH_SUFFIXES include include/linux
+    )
+
+if(NOT LIBMAGIC_MAGIC_H)
+    message(FATAL_ERROR "magic.h not found")
+endif()
+
+add_library(libmagic_static INTERFACE IMPORTED)
+set_property(TARGET libmagic_static PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${LIBMAGIC_MAGIC_H})
+set_property(TARGET libmagic_static PROPERTY INTERFACE_LINK_LIBRARIES ${LIBMAGIC_A})

src/CMakeLists.txt

@@ -1,4 +1,5 @@
 # globally include own includes
 include_directories(${PROJECT_SOURCE_DIR}/include)
 
+add_subdirectory(util)
 add_subdirectory(core)

src/core/CMakeLists.txt

@@ -7,8 +7,11 @@ file(GLOB HEADERS ${PROJECT_SOURCE_DIR}/include/linuxdeploy/core/*.h)
 
 set(Boost_USE_STATIC_LIBS ON)
 find_package(Boost REQUIRED COMPONENTS filesystem regex)
+
 find_package(Threads)
 
+find_package(LibMagic)
+
 find_package(PkgConfig)
 pkg_check_modules(magick++ REQUIRED IMPORTED_TARGET Magick++)
 
@@ -19,9 +22,8 @@ execute_process(
 )
 
 add_library(linuxdeploy_core STATIC elf.cpp log.cpp  appdir.cpp desktopfile.cpp ${HEADERS})
-target_link_libraries(linuxdeploy_core PUBLIC Boost::filesystem Boost::regex subprocess cpp-feather-ini-parser PkgConfig::magick++ ${CMAKE_THREAD_LIBS_INIT})
+target_link_libraries(linuxdeploy_core PUBLIC linuxdeploy_util Boost::filesystem Boost::regex subprocess cpp-feather-ini-parser PkgConfig::magick++ libmagic_static ${CMAKE_THREAD_LIBS_INIT})
 target_include_directories(linuxdeploy_core PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
-target_include_directories(linuxdeploy_core PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../util)
 target_include_directories(linuxdeploy_core PUBLIC ${PROJECT_SOURCE_DIR}/include)
 target_compile_definitions(linuxdeploy_core PUBLIC -DBOOST_NO_CXX11_SCOPED_ENUMS)
 

src/util/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_library(linuxdeploy_util STATIC magicwrapper.cpp magicwrapper.h util.h)
+target_include_directories(linuxdeploy_util PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})

src/util/magicwrapper.cpp

@@ -0,0 +1,49 @@
+// system includes
+#include <magic.h>
+#include <string>
+
+// local includes
+#include "magicwrapper.h"
+
+namespace linuxdeploy {
+    namespace util {
+        namespace magic {
+            class MagicWrapper::PrivateData {
+                private:
+                    magic_t cookie;
+
+                public:
+                    PrivateData() noexcept(false) {
+                        cookie = magic_open(MAGIC_DEBUG | MAGIC_SYMLINK | MAGIC_MIME_TYPE);
+
+                        if (cookie == nullptr)
+                            throw MagicError("Failed to open magic database");
+                    }
+
+                    ~PrivateData() {
+                        if (cookie != nullptr) {
+                            magic_close(cookie);
+                            cookie = nullptr;
+                        }
+                    };
+
+                    std::string fileType(const std::string& path) {
+                        const auto* buf = magic_file(cookie, path.c_str());
+
+                        if (buf == nullptr)
+                            return "";
+
+                        return buf;
+                    }
+            };
+
+            MagicWrapper::MagicWrapper() {
+                d = new PrivateData();
+            }
+
+            MagicWrapper::~MagicWrapper() {
+                delete d;
+            }
+        }
+    }
+}

src/util/magicwrapper.h

@@ -0,0 +1,37 @@
+// system includes
+#include <exception>
+#include <string>
+#include <utility>
+
+#pragma once
+
+namespace linuxdeploy {
+    namespace util {
+        namespace magic {
+            // thrown by constructors if opening the magic database fails
+            class MagicError : std::exception {
+                private:
+                    const std::string message;
+
+                public:
+                    explicit MagicError() : message() {}
+
+                    explicit MagicError(std::string message) : message(std::move(message)) {}
+
+                    const char* what() {
+                        return message.c_str();
+                    }
+            };
+
+            class MagicWrapper {
+                private:
+                    class PrivateData;
+                    PrivateData *d;
+
+                public:
+                    MagicWrapper();
+                    ~MagicWrapper();
+            };
+        }
+    }
+}