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buflib: Allow handle to be freed entirely during the shrink callback.

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Change-Id: I3a069dcb99bbd4022faf37596b03beb926d2ea82
Reviewed-on: http://gerrit.rockbox.org/480
Reviewed-by: Thomas Martitz <kugel@rockbox.org>
Tested-by: Thomas Martitz <kugel@rockbox.org>
This commit is contained in:
Thomas Martitz 2013-05-29 06:48:33 +02:00
parent d938ae692c
commit 46ea8bfe7c
1 changed files with 10 additions and 4 deletions
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14
firmware/buflib.c
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@ -165,7 +165,7 @@ static union buflib_data* handle_to_block(struct buflib_context* ctx, int handle
union buflib_data* name_field = union buflib_data* name_field =
(union buflib_data*)buflib_get_name(ctx, handle); (union buflib_data*)buflib_get_name(ctx, handle);
return name_field - 3; return name_field ? name_field - 3 : NULL;
} }
/* Shrink the handle table, returning true if its size was reduced, false if /* Shrink the handle table, returning true if its size was reduced, false if
@ -353,11 +353,15 @@ buflib_compact_and_shrink(struct buflib_context *ctx, unsigned shrink_hints)
ret = this[2].ops->shrink_callback(handle, shrink_hints, ret = this[2].ops->shrink_callback(handle, shrink_hints,
data, (char*)(this+this->val)-data); data, (char*)(this+this->val)-data);
result |= (ret == BUFLIB_CB_OK); result |= (ret == BUFLIB_CB_OK);
/* this might have changed in the callback (if /* 'this' might have changed in the callback (if it shrinked
* it shrinked from the top), get it again */ * from the top or even freed the handle), get it again */
this = handle_to_block(ctx, handle); this = handle_to_block(ctx, handle);
/* The handle was possibly be freed in the callback,
* re-run the loop with the handle before */
if (!this)
this = before;
/* could also change with shrinking from back */ /* could also change with shrinking from back */
if (last) else if (last)
ctx->alloc_end = this + this->val; ctx->alloc_end = this + this->val;
} }
} }
@ -780,6 +784,8 @@ buflib_shrink(struct buflib_context* ctx, int handle, void* new_start, size_t ne
const char* buflib_get_name(struct buflib_context *ctx, int handle) const char* buflib_get_name(struct buflib_context *ctx, int handle)
{ {
union buflib_data *data = ALIGN_DOWN(buflib_get_data(ctx, handle), sizeof (*data)); union buflib_data *data = ALIGN_DOWN(buflib_get_data(ctx, handle), sizeof (*data));
if (!data)
return NULL;
size_t len = data[-1].val; size_t len = data[-1].val;
if (len <= 1) if (len <= 1)
return NULL; return NULL;