initial commit, 4.5 stable

thirdparty/sdl/SDL_hints.c

@@ -0,0 +1,403 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#include "SDL_hints_c.h"
+
+#ifdef SDL_PLATFORM_ANDROID
+#include "core/android/SDL_android.h"
+#endif
+
+typedef struct SDL_HintWatch
+{
+    SDL_HintCallback callback;
+    void *userdata;
+    struct SDL_HintWatch *next;
+} SDL_HintWatch;
+
+typedef struct SDL_Hint
+{
+    char *value;
+    SDL_HintPriority priority;
+    SDL_HintWatch *callbacks;
+} SDL_Hint;
+
+static SDL_AtomicU32 SDL_hint_props;
+
+
+void SDL_InitHints(void)
+{
+}
+
+void SDL_QuitHints(void)
+{
+    SDL_PropertiesID props;
+    do {
+        props = SDL_GetAtomicU32(&SDL_hint_props);
+    } while (!SDL_CompareAndSwapAtomicU32(&SDL_hint_props, props, 0));
+
+    if (props) {
+        SDL_DestroyProperties(props);
+    }
+}
+
+static SDL_PropertiesID GetHintProperties(bool create)
+{
+    SDL_PropertiesID props = SDL_GetAtomicU32(&SDL_hint_props);
+    if (!props && create) {
+        props = SDL_CreateProperties();
+        if (!SDL_CompareAndSwapAtomicU32(&SDL_hint_props, 0, props)) {
+            // Somebody else created hint properties before us, just use those
+            SDL_DestroyProperties(props);
+            props = SDL_GetAtomicU32(&SDL_hint_props);
+        }
+    }
+    return props;
+}
+
+static void SDLCALL CleanupHintProperty(void *userdata, void *value)
+{
+    SDL_Hint *hint = (SDL_Hint *) value;
+    SDL_free(hint->value);
+
+    SDL_HintWatch *entry = hint->callbacks;
+    while (entry) {
+        SDL_HintWatch *freeable = entry;
+        entry = entry->next;
+        SDL_free(freeable);
+    }
+    SDL_free(hint);
+}
+
+static const char* GetHintEnvironmentVariable(const char *name)
+{
+    const char *result = SDL_getenv(name);
+    if (!result && name && *name) {
+        // fall back to old (SDL2) names of environment variables that
+        // are important to users (e.g. many use SDL_VIDEODRIVER=wayland)
+        if (SDL_strcmp(name, SDL_HINT_VIDEO_DRIVER) == 0) {
+            result = SDL_getenv("SDL_VIDEODRIVER");
+        } else if (SDL_strcmp(name, SDL_HINT_AUDIO_DRIVER) == 0) {
+            result = SDL_getenv("SDL_AUDIODRIVER");
+        }
+    }
+    return result;
+}
+
+bool SDL_SetHintWithPriority(const char *name, const char *value, SDL_HintPriority priority)
+{
+    if (!name || !*name) {
+        return SDL_InvalidParamError("name");
+    }
+
+    const char *env = GetHintEnvironmentVariable(name);
+    if (env && (priority < SDL_HINT_OVERRIDE)) {
+        return SDL_SetError("An environment variable is taking priority");
+    }
+
+    const SDL_PropertiesID hints = GetHintProperties(true);
+    if (!hints) {
+        return false;
+    }
+
+    bool result = false;
+
+    SDL_LockProperties(hints);
+
+    SDL_Hint *hint = (SDL_Hint *)SDL_GetPointerProperty(hints, name, NULL);
+    if (hint) {
+        if (priority >= hint->priority) {
+            if (hint->value != value && (!value || !hint->value || SDL_strcmp(hint->value, value) != 0)) {
+                char *old_value = hint->value;
+
+                hint->value = value ? SDL_strdup(value) : NULL;
+                SDL_HintWatch *entry = hint->callbacks;
+                while (entry) {
+                    // Save the next entry in case this one is deleted
+                    SDL_HintWatch *next = entry->next;
+                    entry->callback(entry->userdata, name, old_value, value);
+                    entry = next;
+                }
+                SDL_free(old_value);
+            }
+            hint->priority = priority;
+            result = true;
+        }
+    } else {  // Couldn't find the hint? Add a new one.
+        hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
+        if (hint) {
+            hint->value = value ? SDL_strdup(value) : NULL;
+            hint->priority = priority;
+            hint->callbacks = NULL;
+            result = SDL_SetPointerPropertyWithCleanup(hints, name, hint, CleanupHintProperty, NULL);
+        }
+    }
+
+#ifdef SDL_PLATFORM_ANDROID
+    if (SDL_strcmp(name, SDL_HINT_ANDROID_ALLOW_RECREATE_ACTIVITY) == 0) {
+        // Special handling for this hint, which needs to persist outside the normal application flow
+        Android_SetAllowRecreateActivity(SDL_GetStringBoolean(value, false));
+    }
+#endif // SDL_PLATFORM_ANDROID
+
+    SDL_UnlockProperties(hints);
+
+    return result;
+}
+
+bool SDL_ResetHint(const char *name)
+{
+    if (!name || !*name) {
+        return SDL_InvalidParamError("name");
+    }
+
+    const char *env = GetHintEnvironmentVariable(name);
+
+    const SDL_PropertiesID hints = GetHintProperties(false);
+    if (!hints) {
+        return false;
+    }
+
+    bool result = false;
+
+    SDL_LockProperties(hints);
+
+    SDL_Hint *hint = (SDL_Hint *)SDL_GetPointerProperty(hints, name, NULL);
+    if (hint) {
+        if ((!env && hint->value) || (env && !hint->value) || (env && SDL_strcmp(env, hint->value) != 0)) {
+            for (SDL_HintWatch *entry = hint->callbacks; entry;) {
+                // Save the next entry in case this one is deleted
+                SDL_HintWatch *next = entry->next;
+                entry->callback(entry->userdata, name, hint->value, env);
+                entry = next;
+            }
+        }
+        SDL_free(hint->value);
+        hint->value = NULL;
+        hint->priority = SDL_HINT_DEFAULT;
+        result = true;
+    }
+
+#ifdef SDL_PLATFORM_ANDROID
+    if (SDL_strcmp(name, SDL_HINT_ANDROID_ALLOW_RECREATE_ACTIVITY) == 0) {
+        // Special handling for this hint, which needs to persist outside the normal application flow
+        if (env) {
+            Android_SetAllowRecreateActivity(SDL_GetStringBoolean(env, false));
+        } else {
+            Android_SetAllowRecreateActivity(false);
+        }
+    }
+#endif // SDL_PLATFORM_ANDROID
+
+    SDL_UnlockProperties(hints);
+
+    return result;
+}
+
+static void SDLCALL ResetHintsCallback(void *userdata, SDL_PropertiesID hints, const char *name)
+{
+    SDL_Hint *hint = (SDL_Hint *)SDL_GetPointerProperty(hints, name, NULL);
+    if (!hint) {
+        return;  // uh...okay.
+    }
+
+    const char *env = GetHintEnvironmentVariable(name);
+    if ((!env && hint->value) || (env && !hint->value) || (env && SDL_strcmp(env, hint->value) != 0)) {
+        SDL_HintWatch *entry = hint->callbacks;
+        while (entry) {
+            // Save the next entry in case this one is deleted
+            SDL_HintWatch *next = entry->next;
+            entry->callback(entry->userdata, name, hint->value, env);
+            entry = next;
+        }
+    }
+    SDL_free(hint->value);
+    hint->value = NULL;
+    hint->priority = SDL_HINT_DEFAULT;
+
+#ifdef SDL_PLATFORM_ANDROID
+    if (SDL_strcmp(name, SDL_HINT_ANDROID_ALLOW_RECREATE_ACTIVITY) == 0) {
+        // Special handling for this hint, which needs to persist outside the normal application flow
+        if (env) {
+            Android_SetAllowRecreateActivity(SDL_GetStringBoolean(env, false));
+        } else {
+            Android_SetAllowRecreateActivity(false);
+        }
+    }
+#endif // SDL_PLATFORM_ANDROID
+}
+
+void SDL_ResetHints(void)
+{
+    SDL_EnumerateProperties(GetHintProperties(false), ResetHintsCallback, NULL);
+}
+
+bool SDL_SetHint(const char *name, const char *value)
+{
+    return SDL_SetHintWithPriority(name, value, SDL_HINT_NORMAL);
+}
+
+const char *SDL_GetHint(const char *name)
+{
+    if (!name) {
+        return NULL;
+    }
+
+    const char *result = GetHintEnvironmentVariable(name);
+
+    const SDL_PropertiesID hints = GetHintProperties(false);
+    if (hints) {
+        SDL_LockProperties(hints);
+
+        SDL_Hint *hint = (SDL_Hint *)SDL_GetPointerProperty(hints, name, NULL);
+        if (hint) {
+            if (!result || hint->priority == SDL_HINT_OVERRIDE) {
+                result = SDL_GetPersistentString(hint->value);
+            }
+        }
+
+        SDL_UnlockProperties(hints);
+    }
+
+    return result;
+}
+
+int SDL_GetStringInteger(const char *value, int default_value)
+{
+    if (!value || !*value) {
+        return default_value;
+    }
+    if (SDL_strcasecmp(value, "false") == 0) {
+        return 0;
+    }
+    if (SDL_strcasecmp(value, "true") == 0) {
+        return 1;
+    }
+    if (*value == '-' || SDL_isdigit(*value)) {
+        return SDL_atoi(value);
+    }
+    return default_value;
+}
+
+bool SDL_GetStringBoolean(const char *value, bool default_value)
+{
+    if (!value || !*value) {
+        return default_value;
+    }
+    if (*value == '0' || SDL_strcasecmp(value, "false") == 0) {
+        return false;
+    }
+    return true;
+}
+
+bool SDL_GetHintBoolean(const char *name, bool default_value)
+{
+    const char *hint = SDL_GetHint(name);
+    return SDL_GetStringBoolean(hint, default_value);
+}
+
+bool SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
+{
+    if (!name || !*name) {
+        return SDL_InvalidParamError("name");
+    } else if (!callback) {
+        return SDL_InvalidParamError("callback");
+    }
+
+    const SDL_PropertiesID hints = GetHintProperties(true);
+    if (!hints) {
+        return false;
+    }
+
+    SDL_HintWatch *entry = (SDL_HintWatch *)SDL_malloc(sizeof(*entry));
+    if (!entry) {
+        return false;
+    }
+    entry->callback = callback;
+    entry->userdata = userdata;
+
+    bool result = false;
+
+    SDL_LockProperties(hints);
+
+    SDL_RemoveHintCallback(name, callback, userdata);
+
+    SDL_Hint *hint = (SDL_Hint *)SDL_GetPointerProperty(hints, name, NULL);
+    if (hint) {
+        result = true;
+    } else {  // Need to add a hint entry for this watcher
+        hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
+        if (!hint) {
+            SDL_free(entry);
+            SDL_UnlockProperties(hints);
+            return false;
+        } else {
+            hint->value = NULL;
+            hint->priority = SDL_HINT_DEFAULT;
+            hint->callbacks = NULL;
+            result = SDL_SetPointerPropertyWithCleanup(hints, name, hint, CleanupHintProperty, NULL);
+        }
+    }
+
+    // Add it to the callbacks for this hint
+    entry->next = hint->callbacks;
+    hint->callbacks = entry;
+
+    // Now call it with the current value
+    const char *value = SDL_GetHint(name);
+    callback(userdata, name, value, value);
+
+    SDL_UnlockProperties(hints);
+
+    return result;
+}
+
+void SDL_RemoveHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
+{
+    if (!name || !*name) {
+        return;
+    }
+
+    const SDL_PropertiesID hints = GetHintProperties(false);
+    if (!hints) {
+        return;
+    }
+
+    SDL_LockProperties(hints);
+    SDL_Hint *hint = (SDL_Hint *)SDL_GetPointerProperty(hints, name, NULL);
+    if (hint) {
+        SDL_HintWatch *prev = NULL;
+        for (SDL_HintWatch *entry = hint->callbacks; entry; entry = entry->next) {
+            if ((callback == entry->callback) && (userdata == entry->userdata)) {
+                if (prev) {
+                    prev->next = entry->next;
+                } else {
+                    hint->callbacks = entry->next;
+                }
+                SDL_free(entry);
+                break;
+            }
+            prev = entry;
+        }
+    }
+    SDL_UnlockProperties(hints);
+}
+