src/plugins/ctf/common/src/metadata/tsdl/objstack.cpp

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Common Trace Format Object Stack.
   7  */
   8
   9 #include "common/align.h"
  10 #include "common/list.h"
  11 #include "cpp-common/bt2c/logging.hpp"
  12
  13 #include "objstack.hpp"
  14
  15 #define OBJSTACK_ALIGN    8 /* Object stack alignment */
  16 #define OBJSTACK_INIT_LEN 128
  17 #define OBJSTACK_POISON   0xcc
  18
  19 struct objstack
  20 {
  21     explicit objstack(const bt2c::Logger& parentLogger) :
  22         logger {parentLogger, "PLUGIN/CTF/META/OBJSTACK"}
  23     {
  24     }
  25
  26     /* list of struct objstack_node */
  27     bt_list_head head {};
  28
  29     bt2c::Logger logger;
  30 };
  31
  32 struct objstack_node
  33 {
  34     struct bt_list_head node;
  35     size_t len;
  36     size_t used_len;
  37     char __attribute__((aligned(OBJSTACK_ALIGN))) data[];
  38 };
  39
  40 objstack *objstack_create(const bt2c::Logger& parentLogger)
  41 {
  42     struct objstack *objstack;
  43     struct objstack_node *node;
  44
  45     objstack = new ::objstack {parentLogger};
  46     node = (objstack_node *) calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN, sizeof(char));
  47     if (!node) {
  48         BT_CPPLOGE_STR_SPEC(objstack->logger, "Failed to allocate one object stack node.");
  49         delete objstack;
  50         return NULL;
  51     }
  52     BT_INIT_LIST_HEAD(&objstack->head);
  53     bt_list_add_tail(&node->node, &objstack->head);
  54     node->len = OBJSTACK_INIT_LEN;
  55     return objstack;
  56 }
  57
  58 static void objstack_node_free(struct objstack_node *node)
  59 {
  60     size_t offset, len;
  61     char *p;
  62
  63     if (!node)
  64         return;
  65     p = (char *) node;
  66     len = sizeof(*node) + node->len;
  67     for (offset = 0; offset < len; offset++)
  68         p[offset] = OBJSTACK_POISON;
  69     free(node);
  70 }
  71
  72 void objstack_destroy(struct objstack *objstack)
  73 {
  74     struct objstack_node *node, *p;
  75
  76     if (!objstack)
  77         return;
  78     bt_list_for_each_entry_safe (node, p, &objstack->head, node) {
  79         bt_list_del(&node->node);
  80         objstack_node_free(node);
  81     }
  82
  83     delete objstack;
  84 }
  85
  86 static struct objstack_node *objstack_append_node(struct objstack *objstack)
  87 {
  88     struct objstack_node *last_node, *new_node;
  89
  90     /* Get last node */
  91     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
  92
  93     /* Allocate new node with double of size of last node */
  94     new_node = (objstack_node *) calloc(sizeof(struct objstack_node) + (last_node->len << 1),
  95                                         sizeof(char));
  96     if (!new_node) {
  97         BT_CPPLOGE_STR_SPEC(objstack->logger, "Failed to allocate one object stack node.");
  98         return NULL;
  99     }
 100     bt_list_add_tail(&new_node->node, &objstack->head);
 101     new_node->len = last_node->len << 1;
 102     return new_node;
 103 }
 104
 105 void *objstack_alloc(struct objstack *objstack, size_t len)
 106 {
 107     struct objstack_node *last_node;
 108     void *p;
 109
 110     len = BT_ALIGN(len, OBJSTACK_ALIGN);
 111
 112     /* Get last node */
 113     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
 114     while (last_node->len - last_node->used_len < len) {
 115         last_node = objstack_append_node(objstack);
 116         if (!last_node) {
 117             return NULL;
 118         }
 119     }
 120     p = &last_node->data[last_node->used_len];
 121     last_node->used_len += len;
 122     return p;
 123 }