/*
 ** Copyright 2007, The Android Open Source Project
 **
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 **
 **     http://www.apache.org/licenses/LICENSE-2.0
 **
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 */

#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <dlfcn.h>
#include <limits.h>
#include <dirent.h>

#include <cutils/log.h>
#include <cutils/properties.h>

#include <EGL/egl.h>

#include "../glestrace.h"

#include "egldefs.h"
#include "Loader.h"

// ----------------------------------------------------------------------------
namespace android {
// ----------------------------------------------------------------------------


/*
 * EGL userspace drivers must be provided either:
 * - as a single library:
 *      /vendor/lib/egl/libGLES.so
 *
 * - as separate libraries:
 *      /vendor/lib/egl/libEGL.so
 *      /vendor/lib/egl/libGLESv1_CM.so
 *      /vendor/lib/egl/libGLESv2.so
 *
 * The software renderer for the emulator must be provided as a single
 * library at:
 *
 *      /system/lib/egl/libGLES_android.so
 *
 *
 * For backward compatibility and to facilitate the transition to
 * this new naming scheme, the loader will additionally look for:
 *
 *      /{vendor|system}/lib/egl/lib{GLES | [EGL|GLESv1_CM|GLESv2]}_*.so
 *
 */

ANDROID_SINGLETON_STATIC_INSTANCE( Loader )

/* This function is called to check whether we run inside the emulator,
 * and if this is the case whether GLES GPU emulation is supported.
 *
 * Returned values are:
 *  -1   -> not running inside the emulator
 *   0   -> running inside the emulator, but GPU emulation not supported
 *   1   -> running inside the emulator, GPU emulation is supported
 *          through the "emulation" config.
 */
static int
checkGlesEmulationStatus(void)
{
    /* We're going to check for the following kernel parameters:
     *
     *    qemu=1                      -> tells us that we run inside the emulator
     *    android.qemu.gles=<number>  -> tells us the GLES GPU emulation status
     *
     * Note that we will return <number> if we find it. This let us support
     * more additionnal emulation modes in the future.
     */
    char  prop[PROPERTY_VALUE_MAX];
    int   result = -1;

    /* Check first if the device does not support hardware rendering */
    property_get("ro.libagl",prop,"0");
    if(atoi(prop) == 1)
        return 0;

    /* Then, check for qemu=1 */
    property_get("ro.kernel.qemu",prop,"0");
    if (atoi(prop) != 1)
        return -1;

    /* We are in the emulator, get GPU status value */
    property_get("ro.kernel.qemu.gles",prop,"0");
    return atoi(prop);
}

// ----------------------------------------------------------------------------

static char const * getProcessCmdline() {
    long pid = getpid();
    char procPath[128];
    snprintf(procPath, 128, "/proc/%ld/cmdline", pid);
    FILE * file = fopen(procPath, "r");
    if (file) {
        static char cmdline[256];
        char *str = fgets(cmdline, sizeof(cmdline) - 1, file);
        fclose(file);
        if (str) {
            return cmdline;
        }
    }
    return NULL;
}

// ----------------------------------------------------------------------------

/* Gets a system-defined per-application path to a GLES implementation.
 * Used when running multiple (usually software) renderers on a single device.
 * Requires ro.zygote.disable_gl_preload to be enabled!
 *
 * It looks for libraries in the filesystem in this preferred order:
 *   /data/data/<application name>/os_override/libGLES_impl.so
 *   /system/etc/os_override/<application name>/libGLES_impl.so
 *
 * Usually, libGLES_impl.so would be a symlink to a GLES implementation.
 *
 * MatchFile::find() does the heavy lifting of using the value.
 * As of writing it searches for the value '/system/lib/libGLES_mesa.so'
 * in this order:
 *
 *   /system/lib/libGLES_mesa.so/lib%s.so
 *   /system/lib/libGLES_mesa.so/lib%s_*.so
 *   /system/lib/libGLES_mesa.so
 *
 * where %s is determined at runtime to be GLES, EGL, GLESv1_CM, or GLESv2.
 */
static const char* getOverridePath(void) {
    // only really useful if ro.zygote.disable_gl_preload is enabled
    // otherwise overrides only happen once, to zygote
    if (!property_get_bool("ro.zygote.disable_gl_preload", 0)) {
            ALOGD("ro.zygote.disable_gl_preload not set,"
                  " EGL overrides disabled");
            return 0;
    }

    String8 data_override_path("/data/data/");
    data_override_path.appendFormat("%s", getProcessCmdline());
    data_override_path.appendFormat("%s", "/os_override/libGLES_impl.so");

    ALOGD("checking %s for override...",
        data_override_path.string());

    if (!access( data_override_path.string(), R_OK ) ) {
        ALOGD("override found: %s", data_override_path.string());
	return data_override_path.string();
    }

    String8 system_override_path("/system/etc/os_override/");
    system_override_path.appendFormat("%s", getProcessCmdline());
    system_override_path.appendFormat("%s", "/libGLES_impl.so");

    ALOGD("checking %s for override...",
        system_override_path.string());

    if (!access( system_override_path.string(), R_OK ) ) {
        ALOGD("override found: %s", system_override_path.string());
	return system_override_path.string();
    }

    ALOGD("no override found");
    return 0;
}

// ----------------------------------------------------------------------------

Loader::driver_t::driver_t(void* gles)
{
    dso[0] = gles;
    for (size_t i=1 ; i<NELEM(dso) ; i++)
        dso[i] = 0;
}

Loader::driver_t::~driver_t()
{
    for (size_t i=0 ; i<NELEM(dso) ; i++) {
        if (dso[i]) {
            dlclose(dso[i]);
            dso[i] = 0;
        }
    }
}

status_t Loader::driver_t::set(void* hnd, int32_t api)
{
    switch (api) {
        case EGL:
            dso[0] = hnd;
            break;
        case GLESv1_CM:
            dso[1] = hnd;
            break;
        case GLESv2:
            dso[2] = hnd;
            break;
        default:
            return BAD_INDEX;
    }
    return NO_ERROR;
}

// ----------------------------------------------------------------------------

Loader::Loader()
    : getProcAddress(NULL) {
}

Loader::~Loader() {
    GLTrace_stop();
}

static void* load_wrapper(const char* path) {
    void* so = dlopen(path, RTLD_NOW | RTLD_LOCAL);
    ALOGE_IF(!so, "dlopen(\"%s\") failed: %s", path, dlerror());
    return so;
}

void* Loader::open(egl_connection_t* cnx)
{
    void* dso;
    driver_t* hnd = 0;

    dso = load_driver("GLES", cnx, EGL | GLESv1_CM | GLESv2);
    if (dso) {
        hnd = new driver_t(dso);
    } else {
        // Always load EGL first
        dso = load_driver("EGL", cnx, EGL);
        if (dso) {
            hnd = new driver_t(dso);
            hnd->set( load_driver("GLESv1_CM", cnx, GLESv1_CM), GLESv1_CM );
            hnd->set( load_driver("GLESv2",    cnx, GLESv2),    GLESv2 );
        }
    }

    LOG_ALWAYS_FATAL_IF(!hnd, "couldn't find an OpenGL ES implementation");

#if defined(__LP64__)
    cnx->libEgl   = load_wrapper("/system/lib64/libEGL.so");
    cnx->libGles2 = load_wrapper("/system/lib64/libGLESv2.so");
    cnx->libGles1 = load_wrapper("/system/lib64/libGLESv1_CM.so");
#else
    cnx->libEgl   = load_wrapper("/system/lib/libEGL.so");
    cnx->libGles2 = load_wrapper("/system/lib/libGLESv2.so");
    cnx->libGles1 = load_wrapper("/system/lib/libGLESv1_CM.so");
#endif
    LOG_ALWAYS_FATAL_IF(!cnx->libEgl,
            "couldn't load system EGL wrapper libraries");

    LOG_ALWAYS_FATAL_IF(!cnx->libGles2 || !cnx->libGles1,
            "couldn't load system OpenGL ES wrapper libraries");

    return (void*)hnd;
}

status_t Loader::close(void* driver)
{
    driver_t* hnd = (driver_t*)driver;
    delete hnd;
    return NO_ERROR;
}

void Loader::init_api(void* dso,
        char const * const * api,
        __eglMustCastToProperFunctionPointerType* curr,
        getProcAddressType getProcAddress)
{
    const ssize_t SIZE = 256;
    char scrap[SIZE];
    while (*api) {
        char const * name = *api;
        __eglMustCastToProperFunctionPointerType f =
            (__eglMustCastToProperFunctionPointerType)dlsym(dso, name);
        if (f == NULL) {
            // couldn't find the entry-point, use eglGetProcAddress()
            f = getProcAddress(name);
        }
        if (f == NULL) {
            // Try without the OES postfix
            ssize_t index = ssize_t(strlen(name)) - 3;
            if ((index>0 && (index<SIZE-1)) && (!strcmp(name+index, "OES"))) {
                strncpy(scrap, name, index);
                scrap[index] = 0;
                f = (__eglMustCastToProperFunctionPointerType)dlsym(dso, scrap);
                //ALOGD_IF(f, "found <%s> instead", scrap);
            }
        }
        if (f == NULL) {
            // Try with the OES postfix
            ssize_t index = ssize_t(strlen(name)) - 3;
            if (index>0 && strcmp(name+index, "OES")) {
                snprintf(scrap, SIZE, "%sOES", name);
                f = (__eglMustCastToProperFunctionPointerType)dlsym(dso, scrap);
                //ALOGD_IF(f, "found <%s> instead", scrap);
            }
        }
        if (f == NULL) {
            //ALOGD("%s", name);
            f = (__eglMustCastToProperFunctionPointerType)gl_unimplemented;

            /*
             * GL_EXT_debug_label is special, we always report it as
             * supported, it's handled by GLES_trace. If GLES_trace is not
             * enabled, then these are no-ops.
             */
            if (!strcmp(name, "glInsertEventMarkerEXT")) {
                f = (__eglMustCastToProperFunctionPointerType)gl_noop;
            } else if (!strcmp(name, "glPushGroupMarkerEXT")) {
                f = (__eglMustCastToProperFunctionPointerType)gl_noop;
            } else if (!strcmp(name, "glPopGroupMarkerEXT")) {
                f = (__eglMustCastToProperFunctionPointerType)gl_noop;
            }
        }
        *curr++ = f;
        api++;
    }
}

void *Loader::load_driver(const char* kind,
        egl_connection_t* cnx, uint32_t mask)
{
    class MatchFile {
    public:
        static String8 find(const char* kind) {
            String8 result;

            // check for overrides first
            const char* overridePath = getOverridePath();
            if (overridePath) {
               result.setTo(overridePath);
               return result;
            }

            // in the emulator case, we just return the hardcoded name
            // of the software renderer.
            if (checkGlesEmulationStatus() == 0) {
                ALOGD("Emulator without GPU support detected. "
                      "Fallback to software renderer.");
#if defined(__LP64__)
                result.setTo("/system/lib64/egl/libGLES_android.so");
#else
                result.setTo("/system/lib/egl/libGLES_android.so");
#endif
                return result;
            }

            const char* const searchPaths[] = {
#if defined(__LP64__)
                    "/vendor/lib64/egl",
                    "/system/lib64/egl"
#else
                    "/vendor/lib/egl",
                    "/system/lib/egl"
#endif
            };

            for (size_t i=0 ; i<NELEM(searchPaths) ; i++) {
                if (search_path(kind, searchPaths[i], result)) {
                    return result;
                }
            }

            // we didn't find the driver. gah.
            result.clear();
            return result;
        }

        static bool search_path(const char* kind, const char* path, String8& result) {
            String8 pattern;

            // first, we search for the exact name of the GLES userspace
            // driver in both locations.
            // i.e.:
            //      libGLES.so, or:
            //      libEGL.so, libGLESv1_CM.so, libGLESv2.so

            pattern.appendFormat("lib%s", kind);
            if (find(result, pattern, path, true)) {
                return true;
            }

            // for compatibility with the old "egl.cfg" naming convention
            // we look for files that match:
            //      libGLES_*.so, or:
            //      libEGL_*.so, libGLESv1_CM_*.so, libGLESv2_*.so

            pattern.append("_");
            if (find(result, pattern, path, false)) {
                return true;
            }

            return false;
        }

    private:
        static bool find(String8& result,
                const String8& pattern, const char* const search, bool exact) {

            if (exact) {
                String8 absolutePath;
                absolutePath.appendFormat("%s/%s.so", search, pattern.string());
                if (!access(absolutePath.string(), R_OK)) {
                    result = absolutePath;
                    return true;
                }
                return false;
            }

            DIR* d = opendir(search);
            if (d != NULL) {
                struct dirent cur;
                struct dirent* e;
                while (readdir_r(d, &cur, &e) == 0 && e) {
                    if (e->d_type == DT_DIR) {
                        continue;
                    }
                    if (!strcmp(e->d_name, "libGLES_android.so")) {
                        // always skip the software renderer
                        continue;
                    }
                    if (strstr(e->d_name, pattern.string()) == e->d_name) {
                        if (!strcmp(e->d_name + strlen(e->d_name) - 3, ".so")) {
                            result.clear();
                            result.appendFormat("%s/%s", search, e->d_name);
                            closedir(d);
                            return true;
                        }
                    }
                }
                closedir(d);
            }
            return false;
        }
    };


    String8 absolutePath = MatchFile::find(kind);
    if (absolutePath.isEmpty()) {
        // this happens often, we don't want to log an error
        return 0;
    }
    const char* const driver_absolute_path = absolutePath.string();

    void* dso = dlopen(driver_absolute_path, RTLD_NOW | RTLD_LOCAL);
    if (dso == 0) {
        const char* err = dlerror();
        ALOGE("load_driver(%s): %s", driver_absolute_path, err?err:"unknown");
        return 0;
    }

    ALOGD("loaded %s", driver_absolute_path);

    if (mask & EGL) {
        getProcAddress = (getProcAddressType)dlsym(dso, "eglGetProcAddress");

        ALOGE_IF(!getProcAddress,
                "can't find eglGetProcAddress() in %s", driver_absolute_path);

        egl_t* egl = &cnx->egl;
        __eglMustCastToProperFunctionPointerType* curr =
            (__eglMustCastToProperFunctionPointerType*)egl;
        char const * const * api = egl_names;
        while (*api) {
            char const * name = *api;
            __eglMustCastToProperFunctionPointerType f =
                (__eglMustCastToProperFunctionPointerType)dlsym(dso, name);
            if (f == NULL) {
                // couldn't find the entry-point, use eglGetProcAddress()
                f = getProcAddress(name);
                if (f == NULL) {
                    f = (__eglMustCastToProperFunctionPointerType)0;
                }
            }
            *curr++ = f;
            api++;
        }
    }

    if (mask & GLESv1_CM) {
        init_api(dso, gl_names,
            (__eglMustCastToProperFunctionPointerType*)
                &cnx->hooks[egl_connection_t::GLESv1_INDEX]->gl,
            getProcAddress);
    }

    if (mask & GLESv2) {
      init_api(dso, gl_names,
            (__eglMustCastToProperFunctionPointerType*)
                &cnx->hooks[egl_connection_t::GLESv2_INDEX]->gl,
            getProcAddress);
    }

    return dso;
}

// ----------------------------------------------------------------------------
}; // namespace android
// ----------------------------------------------------------------------------
