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#include "stdafx.h"
#include "Driver.h"
#include "Exception.h"
#include "Core/Convert.h"
#ifdef POSIX
#include <dlfcn.h>
#endif
namespace sql {
// Note: These are globals, as loading of dynamic libraries is truly a global concern. It is not
// tied to different Engines.
// Lock to protect globals here.
util::Lock driverLock;
// Instances that are active.
size_t instances = 0;
// Pointer to the "mysql_init" function.
typedef MYSQL *(STDCALL *InitFn)(MYSQL *);
InitFn mariadbInitFn = null;
#if defined(WINDOWS)
// MSVC "hack" to get the address of the module:
extern "C" IMAGE_DOS_HEADER __ImageBase;
InitFn findDriverLib(Engine &e) {
#ifdef X64
const char *fnName = "mysql_init";
#else
const char *fnName = "_mysql_init@4";
#endif
const char *names[] = {
"libmariadb.dll",
#ifdef X64
"libmariadb_64.dll",
#else
"libmariadb_32.dll",
#endif
};
HMODULE moduleHandle = (HMODULE)&__ImageBase;
#if 0
// Try to get the current DLL handle. Only needed if we are not compiling on MSVC.
if (!GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS
| GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
(LPWSTR)&findDriverLib, // ptr to some function in the modle
&moduleHandle)) {
throw new (e) SQLError(new (e) Str(S("Could not find the path to the SQL lib DLL file.")));
}
#endif
std::vector<wchar_t> buffer(MAX_PATH + 1, 0);
do {
GetModuleFileName(moduleHandle, &buffer[0], DWORD(buffer.size()));
if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
buffer.resize(buffer.size() * 2);
continue;
}
} while (false);
// Find the last backslash:
size_t pathEnd = buffer.size();
while (pathEnd > 0) {
if (buffer[pathEnd - 1] == '\\' || buffer[pathEnd - 1] == '/')
break;
pathEnd--;
}
// Try all names:
for (size_t i = 0; i < ARRAY_COUNT(names); i++) {
buffer.resize(pathEnd + strlen(names[i]) + 1);
for (size_t j = 0; names[i][j]; j++)
buffer[pathEnd + j] = names[i][j];
buffer[buffer.size() - 1] = 0;
HMODULE lib = LoadLibrary(&buffer[0]);
if (!lib)
continue;
void *fn = GetProcAddress(lib, fnName);
if (!fn) {
FreeLibrary(lib);
continue;
}
return reinterpret_cast<InitFn>(fn);
}
// We failed. Generate a nice error message!
StrBuf *msg = new (e) StrBuf();
*msg << S("Failed to load the MariaDB library. Looked in the following locations:");
for (size_t i = 0; i < ARRAY_COUNT(names); i++) {
buffer.resize(pathEnd + strlen(names[i]) + 1);
for (size_t j = 0; names[i][j]; j++)
buffer[pathEnd + j] = names[i][j];
buffer[buffer.size() - 1] = 0;
*msg << S("\n") << &buffer[0];
}
throw new (e) SQLError(msg->toS());
}
#elif defined(POSIX)
InitFn findDriverLib(Engine &e) {
const char *fnName = "mysql_init";
const char *names[] = {
"libmariadb.so.3",
null
};
const char *libName = null;
void *loaded = null;
for (const char **name = names; loaded == null && *name != null; name++) {
// Note: This respects rpath of the library if we set it.
libName = *name;
loaded = dlopen(libName, RTLD_NOW | RTLD_LOCAL);
}
if (!loaded) {
StrBuf *msg = new (e) StrBuf();
*msg << S("Failed to load the MariaDB library. Is it installed?\n");
*msg << S("Searched for the following names:");
for (const char **name = names; loaded == null && *name != null; name++) {
*msg << S("\n") << toWChar(e, *name)->v;
}
throw new (e) SQLError(msg->toS());
}
void *symbol = dlsym(loaded, fnName);
if (!symbol) {
StrBuf *msg = new (e) StrBuf();
*msg << S("Failed to find the function ") << toWChar(e, fnName)->v
<< S(" in the shared library ") << libName << S(".");
throw new (e) SQLError(msg->toS());
}
return reinterpret_cast<InitFn>(symbol);
}
#endif
MYSQL *createMariaDBDriver(Engine &e) {
util::Lock::L z(driverLock);
if (!mariadbInitFn)
mariadbInitFn = findDriverLib(e);
MYSQL *result = (*mariadbInitFn)(NULL);
if (!result)
throw new (e) SQLError(new (e) Str(S("Failed to create an instance of the MySQL/MariaDB driver.")));
instances++;
return result;
}
void destroyMariaDBDriver(MYSQL *driver) {
// Close it.
(*driver->methods->api->mysql_close)(driver);
util::Lock::L z(driverLock);
instances--;
// TODO: We don't want to unload immediately, but might be relevant to unload after a while
// of inactivity?
}
}
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