[MOD/WIP] Start separating the main DB API

Not everything is available as of now, I'm still working on it, but it
builds and seems to work, and its 9PM, so that's worthapush.

src/Db/Db.c

@@ -0,0 +1,576 @@
+/*
+ * Copyright (C) 2022-2024 Jordan Bancino <@jordan:bancino.net>
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <Db.h>
+
+#include <Memory.h>
+#include <Json.h>
+#include <Util.h>
+#include <Str.h>
+#include <Stream.h>
+#include <Log.h>
+
+#include <sys/types.h>
+#include <dirent.h>
+
+#include <pthread.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <errno.h>
+#include <string.h>
+
+#include "Db/Internal.h"
+
+void
+StringArrayFree(Array * arr)
+{
+    size_t i;
+
+    for (i = 0; i < ArraySize(arr); i++)
+    {
+        Free(ArrayGet(arr, i));
+    }
+
+    ArrayFree(arr);
+}
+
+static ssize_t DbComputeSize(HashMap *);
+
+static ssize_t
+DbComputeSizeOfValue(JsonValue * val)
+{
+    MemoryInfo *a;
+    ssize_t total = 0;
+
+    size_t i;
+
+    union
+    {
+        char *str;
+        Array *arr;
+    } u;
+
+    if (!val)
+    {
+        return -1;
+    }
+
+    a = MemoryInfoGet(val);
+    if (a)
+    {
+        total += MemoryInfoGetSize(a);
+    }
+
+    switch (JsonValueType(val))
+    {
+        case JSON_OBJECT:
+            total += DbComputeSize(JsonValueAsObject(val));
+            break;
+        case JSON_ARRAY:
+            u.arr = JsonValueAsArray(val);
+            a = MemoryInfoGet(u.arr);
+
+            if (a)
+            {
+                total += MemoryInfoGetSize(a);
+            }
+
+            for (i = 0; i < ArraySize(u.arr); i++)
+            {
+                total += DbComputeSizeOfValue(ArrayGet(u.arr, i));
+            }
+            break;
+        case JSON_STRING:
+            u.str = JsonValueAsString(val);
+            a = MemoryInfoGet(u.str);
+            if (a)
+            {
+                total += MemoryInfoGetSize(a);
+            }
+            break;
+        case JSON_NULL:
+        case JSON_INTEGER:
+        case JSON_FLOAT:
+        case JSON_BOOLEAN:
+        default:
+            /* These don't use any extra heap space */
+            break;
+    }
+    return total;
+}
+
+static ssize_t
+DbComputeSize(HashMap * json)
+{
+    char *key;
+    JsonValue *val;
+    MemoryInfo *a;
+    size_t total;
+
+    if (!json)
+    {
+        return -1;
+    }
+
+    total = 0;
+
+    a = MemoryInfoGet(json);
+    if (a)
+    {
+        total += MemoryInfoGetSize(a);
+    }
+
+    while (HashMapIterate(json, &key, (void **) &val))
+    {
+        a = MemoryInfoGet(key);
+        if (a)
+        {
+            total += MemoryInfoGetSize(a);
+        }
+
+        total += DbComputeSizeOfValue(val);
+    }
+
+    return total;
+}
+
+static char *
+DbHashKey(Array * args)
+{
+    size_t i;
+    char *str = NULL;
+
+    for (i = 0; i < ArraySize(args); i++)
+    {
+        char *tmp = StrConcat(2, str, ArrayGet(args, i));
+
+        Free(str);
+        str = tmp;
+    }
+
+    return str;
+}
+
+static void
+DbCacheEvict(Db * db)
+{
+    DbRef *ref = db->leastRecent;
+    DbRef *tmp;
+
+    while (ref && db->cacheSize > db->maxCache)
+    {
+        char *hash;
+
+        JsonFree(ref->json);
+
+        hash = DbHashKey(ref->name);
+        HashMapDelete(db->cache, hash);
+        Free(hash);
+
+        StringArrayFree(ref->name);
+
+        db->cacheSize -= ref->size;
+
+        if (ref->next)
+        {
+            ref->next->prev = ref->prev;
+        }
+        else
+        {
+            db->mostRecent = ref->prev;
+        }
+
+        if (ref->prev)
+        {
+            ref->prev->next = ref->next;
+        }
+        else
+        {
+            db->leastRecent = ref->next;
+        }
+
+        tmp = ref->next;
+        Free(ref);
+
+        ref = tmp;
+    }
+}
+
+void
+DbMaxCacheSet(Db * db, size_t cache)
+{
+    if (!db)
+    {
+        return;
+    }
+
+    pthread_mutex_lock(&db->lock);
+
+    db->maxCache = cache;
+    if (db->maxCache && !db->cache)
+    {
+        db->cache = HashMapCreate();
+        db->cacheSize = 0;
+    }
+
+    DbCacheEvict(db);
+
+    pthread_mutex_unlock(&db->lock);
+}
+
+void
+DbClose(Db * db)
+{
+    if (!db)
+    {
+        return;
+    }
+
+    pthread_mutex_lock(&db->lock);
+    if (db->close)
+    {
+        db->close(db);
+    }
+    DbMaxCacheSet(db, 0);
+    DbCacheEvict(db);
+    HashMapFree(db->cache);
+
+    pthread_mutex_unlock(&db->lock);
+    pthread_mutex_destroy(&db->lock);
+
+    Free(db);
+}
+
+DbRef *
+DbCreate(Db * db, size_t nArgs,...)
+{
+    va_list ap;
+    Array *args;
+    DbRef *ret;
+
+    if (!db || !db->create)
+    {
+        return NULL;
+    }
+
+    va_start(ap, nArgs);
+    args = ArrayFromVarArgs(nArgs, ap);
+    va_end(ap);
+
+    if (!args)
+    {
+        return NULL;
+    }
+
+    ret = db->create(db, args);
+    ArrayFree(args);
+
+    return ret;
+}
+
+bool
+DbDelete(Db * db, size_t nArgs,...)
+{
+    (void) nArgs;
+    (void) db;
+    /* TODO */
+    /*va_list ap;
+    Array *args;
+    char *file;
+    char *hash;
+    bool ret = true;
+    DbRef *ref;
+
+    if (!db)
+    {
+        return false;
+    }
+
+    va_start(ap, nArgs);
+    args = ArrayFromVarArgs(nArgs, ap);
+    va_end(ap);
+
+    pthread_mutex_lock(&db->lock);
+
+    hash = DbHashKey(args);
+    file = DbFileName(db, args);
+
+    ref = HashMapGet(db->cache, hash);
+    if (ref)
+    {
+        HashMapDelete(db->cache, hash);
+        JsonFree(ref->json);
+        StringArrayFree(ref->name);
+
+        db->cacheSize -= ref->size;
+
+        if (ref->next)
+        {
+            ref->next->prev = ref->prev;
+        }
+        else
+        {
+            db->mostRecent = ref->prev;
+        }
+
+        if (ref->prev)
+        {
+            ref->prev->next = ref->next;
+        }
+        else
+        {
+            db->leastRecent = ref->next;
+        }
+
+        if (!db->leastRecent)
+        {
+            db->leastRecent = db->mostRecent;
+        }
+
+        Free(ref);
+    }
+
+    Free(hash);
+
+    if (UtilLastModified(file))
+    {
+        ret = (remove(file) == 0);
+    }
+
+    pthread_mutex_unlock(&db->lock);
+
+    ArrayFree(args);
+    Free(file);
+    return ret;*/
+    return false;
+}
+
+DbRef *
+DbLock(Db * db, size_t nArgs,...)
+{
+    va_list ap;
+    Array *args;
+    DbRef *ret;
+
+    va_start(ap, nArgs);
+    args = ArrayFromVarArgs(nArgs, ap);
+    va_end(ap);
+
+    if (!args || !db->lockFunc)
+    {
+        return NULL;
+    }
+
+    ret = db->lockFunc(db, args);
+
+    ArrayFree(args);
+
+    return ret;
+}
+
+bool
+DbUnlock(Db * db, DbRef * ref)
+{
+    if (!db || !ref || !db->unlock)
+    {
+        return false;
+    }
+    
+    return db->unlock(db, ref);
+}
+
+bool
+DbExists(Db * db, size_t nArgs,...)
+{
+    (void) nArgs;
+    (void) db;
+    return false;
+    /*va_list ap;
+    Array *args;
+    char *file;
+    bool ret;
+
+    va_start(ap, nArgs);
+    args = ArrayFromVarArgs(nArgs, ap);
+    va_end(ap);
+
+    if (!args)
+    {
+        return false;
+    }
+
+    pthread_mutex_lock(&db->lock);
+
+    file = DbFileName(db, args);
+    ret = (UtilLastModified(file) != 0);
+
+    pthread_mutex_unlock(&db->lock);
+
+    Free(file);
+    ArrayFree(args);
+
+    return ret;*/
+}
+
+Array *
+DbList(Db * db, size_t nArgs,...)
+{
+    (void) db;
+    (void) nArgs;
+    /* TODO */
+    /*Array *result;
+    Array *path;
+    DIR *files;
+    struct dirent *file;
+    char *dir;
+    va_list ap;
+
+    if (!db || !nArgs)
+    {
+        return NULL;
+    }
+
+    result = ArrayCreate();
+    if (!result)
+    {
+        return NULL;
+    }
+
+    va_start(ap, nArgs);
+    path = ArrayFromVarArgs(nArgs, ap);
+    dir = DbDirName(db, path, 0);
+
+    pthread_mutex_lock(&db->lock);
+
+    files = opendir(dir);
+    if (!files)
+    {
+        ArrayFree(path);
+        ArrayFree(result);
+        Free(dir);
+        pthread_mutex_unlock(&db->lock);
+        return NULL;
+    }
+    while ((file = readdir(files)))
+    {
+        size_t namlen = strlen(file->d_name);
+
+        if (namlen > 5)
+        {
+            int nameOffset = namlen - 5;
+
+            if (StrEquals(file->d_name + nameOffset, ".json"))
+            {
+                file->d_name[nameOffset] = '\0';
+                ArrayAdd(result, StrDuplicate(file->d_name));
+            }
+        }
+    }
+    closedir(files);
+
+    ArrayFree(path);
+    Free(dir);
+    pthread_mutex_unlock(&db->lock);
+
+    return result;*/
+    return NULL;
+}
+
+void
+DbListFree(Array * arr)
+{
+    StringArrayFree(arr);
+}
+
+HashMap *
+DbJson(DbRef * ref)
+{
+    return ref ? ref->json : NULL;
+}
+
+bool
+DbJsonSet(DbRef * ref, HashMap * json)
+{
+    if (!ref || !json)
+    {
+        return false;
+    }
+
+    JsonFree(ref->json);
+    ref->json = JsonDuplicate(json);
+    return true;
+}
+void
+DbInit(Db *db)
+{
+    pthread_mutexattr_t attr;
+    if (!db)
+    {
+        return;
+    }
+
+    pthread_mutexattr_init(&attr);
+    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+    pthread_mutex_init(&db->lock, &attr);
+    pthread_mutexattr_destroy(&attr);
+
+    db->mostRecent = NULL;
+    db->leastRecent = NULL;
+    db->cacheSize = 0;
+
+    if (db->maxCache)
+    {
+        db->cache = HashMapCreate();
+    }
+    else
+    {
+        db->cache = NULL;
+    }
+}
+void
+DbRefInit(Db *db, DbRef *ref)
+{
+    if (!db || !ref)
+    {
+        return;
+    }
+    ref->prev = db->mostRecent;
+    ref->next = NULL;
+    ref->json = NULL;
+    ref->name = NULL;
+
+    /* As default values to be overwritten by impls */
+    ref->ts = UtilTsMillis();
+    ref->size = 0;
+
+    if (db->mostRecent)
+    {
+        db->mostRecent->next = ref;
+    }
+    if (!db->leastRecent)
+    {
+        db->leastRecent = ref;
+    }
+    db->mostRecent = ref;
+}