database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-08-08 14:02:16 +03:00
Code Activity

Minor cleanups and additions in sqlite3.capi.wasm.pstack.

Browse Source 
FossilOrigin-Name: 97bd670d3859bd3f2e62c15065b238b85ef614f26479e56a14be42c5784aedf4
This commit is contained in:
stephan
2022-10-04 01:11:10 +00:00
parent 3c272ba380
commit 2b776ee2d6
6 changed files with 159 additions and 138 deletions
Download Patch File Download Diff File Expand all files Collapse all files

51
ext/wasm/api/sqlite3-wasm.c
View File

@@ -135,13 +135,13 @@ WASM_KEEP void * sqlite3_wasm_stack_begin(void){
extern void __data_end;
return &__data_end;
}
static void * sq3StackPtr = 0;
static void * pWasmStackPtr = 0;
WASM_KEEP void * sqlite3_wasm_stack_ptr(void){
if(!sq3StackPtr) sq3StackPtr = sqlite3_wasm_stack_end();
return sq3StackPtr;
if(!pWasmStackPtr) pWasmStackPtr = sqlite3_wasm_stack_end();
return pWasmStackPtr;
}
WASM_KEEP void sqlite3_wasm_stack_restore(void * p){
sq3StackPtr = p;
pWasmStackPtr = p;
}
WASM_KEEP void * sqlite3_wasm_stack_alloc(int n){
if(n<=0) return 0;
@@ -149,7 +149,7 @@ WASM_KEEP void * sqlite3_wasm_stack_alloc(int n){
unsigned char * const p = (unsigned char *)sqlite3_wasm_stack_ptr();
unsigned const char * const b = (unsigned const char *)sqlite3_wasm_stack_begin();
if(b + n >= p || b + n < b/*overflow*/) return 0;
return sq3StackPtr = p - n;
return pWasmStackPtr = p - n;
}
#endif /* stack allocator experiment */
@@ -205,10 +205,9 @@ WASM_KEEP void * sqlite3_wasm_pstack_alloc(int n){
if( n<=0 ) return 0;
//if( n & 0x7 ) n += 8 - (n & 0x7) /* align to 8-byte boundary */;
n = (n + 7) & ~7 /* align to 8-byte boundary */;
unsigned char * const p = PStack.pPos;
unsigned const char * const b = PStack.pBegin;
if( b + n > p || b + n <= b/*overflow*/ ) return 0;
memset((PStack.pPos = p - n), 0, (unsigned int)n);
if( PStack.pBegin + n > PStack.pPos /*not enough space left*/
|| PStack.pBegin + n <= PStack.pBegin /*overflow*/ ) return 0;
memset((PStack.pPos = PStack.pPos - n), 0, (unsigned int)n);
return PStack.pPos;
}
/*
@@ -221,6 +220,14 @@ WASM_KEEP int sqlite3_wasm_pstack_remaining(void){
return (int)(PStack.pPos - PStack.pBegin);
}
/*
** Return the total number of bytes available in the pstack, including
** any space which is currently allocated. This value is a
** compile-time constant.
*/
WASM_KEEP int sqlite3_wasm_pstack_quota(void){
return (int)(PStack.pEnd - PStack.pBegin);
}
/*
** This function is NOT part of the sqlite3 public API. It is strictly
@@ -254,26 +261,26 @@ int sqlite3_wasm_db_error(sqlite3*db, int err_code, const char *zMsg){
** variadic macros.
**
** Returns a string containing a JSON-format "enum" of C-level
** constants intended to be imported into the JS environment. The JSON
** is initialized the first time this function is called and that
** result is reused for all future calls.
** constants and struct-related metadata intended to be imported into
** the JS environment. The JSON is initialized the first time this
** function is called and that result is reused for all future calls.
**
** If this function returns NULL then it means that the internal
** buffer is not large enough for the generated JSON. In debug builds
** that will trigger an assert().
** buffer is not large enough for the generated JSON and needs to be
** increased. In debug builds that will trigger an assert().
*/
WASM_KEEP
const char * sqlite3_wasm_enum_json(void){
static char azBuffer[1024 * 12] = {0} /* where the JSON goes */;
static char aBuffer[1024 * 12] = {0} /* where the JSON goes */;
int n = 0, nChildren = 0, nStruct = 0
/* output counters for figuring out where commas go */;
char * zPos = &azBuffer[1] /* skip first byte for now to help protect
char * zPos = &aBuffer[1] /* skip first byte for now to help protect
** against a small race condition */;
char const * const zEnd = &azBuffer[0] + sizeof(azBuffer) /* one-past-the-end */;
if(azBuffer[0]) return azBuffer;
/* Leave azBuffer[0] at 0 until the end to help guard against a tiny
char const * const zEnd = &aBuffer[0] + sizeof(aBuffer) /* one-past-the-end */;
if(aBuffer[0]) return aBuffer;
/* Leave aBuffer[0] at 0 until the end to help guard against a tiny
** race condition. If this is called twice concurrently, they might
** end up both writing to azBuffer, but they'll both write the same
** end up both writing to aBuffer, but they'll both write the same
** thing, so that's okay. If we set byte 0 up front then the 2nd
** instance might return and use the string before the 1st instance
** is done filling it. */
@@ -680,8 +687,8 @@ const char * sqlite3_wasm_enum_json(void){
out("}"/*top-level object*/);
*zPos = 0;
azBuffer[0] = '{'/*end of the race-condition workaround*/;
return azBuffer;
aBuffer[0] = '{'/*end of the race-condition workaround*/;
return aBuffer;
#undef StructBinder
#undef StructBinder_
#undef StructBinder__