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https://github.com/postgres/postgres.git
synced 2025-06-26 12:21:12 +03:00
Simplify and standardize conversions between TEXT datums and ordinary C
strings. This patch introduces four support functions cstring_to_text, cstring_to_text_with_len, text_to_cstring, and text_to_cstring_buffer, and two macros CStringGetTextDatum and TextDatumGetCString. A number of existing macros that provided variants on these themes were removed. Most of the places that need to make such conversions now require just one function or macro call, in place of the multiple notational layers that used to be needed. There are no longer any direct calls of textout or textin, and we got most of the places that were using handmade conversions via memcpy (there may be a few still lurking, though). This commit doesn't make any serious effort to eliminate transient memory leaks caused by detoasting toasted text objects before they reach text_to_cstring. We changed PG_GETARG_TEXT_P to PG_GETARG_TEXT_PP in a few places where it was easy, but much more could be done. Brendan Jurd and Tom Lane
This commit is contained in:
Tom Lane
@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.163 2008/03/13 18:31:56 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.164 2008/03/25 22:42:44 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -48,15 +48,6 @@ typedef struct
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#define PG_GETARG_UNKNOWN_P_COPY(n) DatumGetUnknownPCopy(PG_GETARG_DATUM(n))
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#define PG_RETURN_UNKNOWN_P(x) PG_RETURN_POINTER(x)
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#define PG_TEXTARG_GET_STR(arg_) \
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DatumGetCString(DirectFunctionCall1(textout, PG_GETARG_DATUM(arg_)))
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#define PG_TEXT_GET_STR(textp_) \
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DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp_)))
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#define PG_STR_GET_TEXT(str_) \
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DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(str_)))
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#define TEXTLEN(textp) \
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text_length(PointerGetDatum(textp))
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static int text_cmp(text *arg1, text *arg2);
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static int32 text_length(Datum str);
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static int text_position(text *t1, text *t2);
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@ -67,10 +58,107 @@ static text *text_substring(Datum str,
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int32 start,
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int32 length,
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bool length_not_specified);
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static void appendStringInfoText(StringInfo str, const text *t);
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/*****************************************************************************
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* CONVERSION ROUTINES EXPORTED FOR USE BY C CODE *
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*****************************************************************************/
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/*
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* cstring_to_text
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*
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* Create a text value from a null-terminated C string.
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*
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* The new text value is freshly palloc'd with a full-size VARHDR.
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*/
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text *
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cstring_to_text(const char *s)
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{
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return cstring_to_text_with_len(s, strlen(s));
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}
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/*
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* cstring_to_text_with_len
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*
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* Same as cstring_to_text except the caller specifies the string length;
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* the string need not be null_terminated.
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*/
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text *
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cstring_to_text_with_len(const char *s, int len)
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{
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text *result = (text *) palloc(len + VARHDRSZ);
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SET_VARSIZE(result, len + VARHDRSZ);
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memcpy(VARDATA(result), s, len);
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return result;
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}
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/*
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* text_to_cstring
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*
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* Create a palloc'd, null-terminated C string from a text value.
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*
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* We support being passed a compressed or toasted text value.
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* This is a bit bogus since such values shouldn't really be referred to as
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* "text *", but it seems useful for robustness. If we didn't handle that
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* case here, we'd need another routine that did, anyway.
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*/
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char *
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text_to_cstring(const text *t)
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{
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/* must cast away the const, unfortunately */
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text *tunpacked = pg_detoast_datum_packed((struct varlena *) t);
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int len = VARSIZE_ANY_EXHDR(tunpacked);
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char *result;
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result = (char *) palloc(len + 1);
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memcpy(result, VARDATA_ANY(tunpacked), len);
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result[len] = '\0';
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if (tunpacked != t)
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pfree(tunpacked);
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return result;
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}
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/*
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* text_to_cstring_buffer
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*
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* Copy a text value into a caller-supplied buffer of size dst_len.
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*
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* The text string is truncated if necessary to fit. The result is
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* guaranteed null-terminated (unless dst_len == 0).
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*
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* We support being passed a compressed or toasted text value.
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* This is a bit bogus since such values shouldn't really be referred to as
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* "text *", but it seems useful for robustness. If we didn't handle that
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* case here, we'd need another routine that did, anyway.
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*/
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void
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text_to_cstring_buffer(const text *src, char *dst, size_t dst_len)
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{
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/* must cast away the const, unfortunately */
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text *srcunpacked = pg_detoast_datum_packed((struct varlena *) src);
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size_t src_len = VARSIZE_ANY_EXHDR(srcunpacked);
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if (dst_len > 0)
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{
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dst_len--;
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if (dst_len >= src_len)
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dst_len = src_len;
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else /* ensure truncation is encoding-safe */
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dst_len = pg_mbcliplen(VARDATA_ANY(srcunpacked), src_len, dst_len);
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memcpy(dst, VARDATA_ANY(srcunpacked), dst_len);
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dst[dst_len] = '\0';
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}
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if (srcunpacked != src)
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pfree(srcunpacked);
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}
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/*****************************************************************************
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* USER I/O ROUTINES *
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*****************************************************************************/
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@ -259,16 +347,8 @@ Datum
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textin(PG_FUNCTION_ARGS)
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{
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char *inputText = PG_GETARG_CSTRING(0);
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text *result;
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int len;
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len = strlen(inputText);
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result = (text *) palloc(len + VARHDRSZ);
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SET_VARSIZE(result, len + VARHDRSZ);
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memcpy(VARDATA(result), inputText, len);
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PG_RETURN_TEXT_P(result);
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PG_RETURN_TEXT_P(cstring_to_text(inputText));
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}
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/*
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@ -277,16 +357,9 @@ textin(PG_FUNCTION_ARGS)
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Datum
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textout(PG_FUNCTION_ARGS)
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{
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text *t = PG_GETARG_TEXT_PP(0);
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int len;
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char *result;
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Datum txt = PG_GETARG_DATUM(0);
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len = VARSIZE_ANY_EXHDR(t);
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result = (char *) palloc(len + 1);
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memcpy(result, VARDATA_ANY(t), len);
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result[len] = '\0';
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PG_RETURN_CSTRING(result);
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PG_RETURN_CSTRING(TextDatumGetCString(txt));
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}
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/*
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@ -302,9 +375,7 @@ textrecv(PG_FUNCTION_ARGS)
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str = pq_getmsgtext(buf, buf->len - buf->cursor, &nbytes);
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result = (text *) palloc(nbytes + VARHDRSZ);
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SET_VARSIZE(result, nbytes + VARHDRSZ);
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memcpy(VARDATA(result), str, nbytes);
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result = cstring_to_text_with_len(str, nbytes);
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pfree(str);
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PG_RETURN_TEXT_P(result);
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}
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@ -600,7 +671,7 @@ text_substring(Datum str, int32 start, int32 length, bool length_not_specified)
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* string.
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*/
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if (E < 1)
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return PG_STR_GET_TEXT("");
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return cstring_to_text("");
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L1 = E - S1;
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}
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@ -664,7 +735,7 @@ text_substring(Datum str, int32 start, int32 length, bool length_not_specified)
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* string.
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*/
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if (E < 1)
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return PG_STR_GET_TEXT("");
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return cstring_to_text("");
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/*
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* if E is past the end of the string, the tuple toaster will
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@ -693,7 +764,7 @@ text_substring(Datum str, int32 start, int32 length, bool length_not_specified)
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{
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if (slice != (text *) DatumGetPointer(str))
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pfree(slice);
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return PG_STR_GET_TEXT("");
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return cstring_to_text("");
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}
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/* Now we can get the actual length of the slice in MB characters */
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@ -708,7 +779,7 @@ text_substring(Datum str, int32 start, int32 length, bool length_not_specified)
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{
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if (slice != (text *) DatumGetPointer(str))
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pfree(slice);
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return PG_STR_GET_TEXT("");
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return cstring_to_text("");
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}
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/*
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@ -1759,16 +1830,8 @@ Datum
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name_text(PG_FUNCTION_ARGS)
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{
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Name s = PG_GETARG_NAME(0);
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text *result;
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int len;
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len = strlen(NameStr(*s));
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result = palloc(VARHDRSZ + len);
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SET_VARSIZE(result, VARHDRSZ + len);
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memcpy(VARDATA(result), NameStr(*s), len);
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PG_RETURN_TEXT_P(result);
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PG_RETURN_TEXT_P(cstring_to_text(NameStr(*s)));
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}
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@ -1790,8 +1853,7 @@ textToQualifiedNameList(text *textval)
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/* Convert to C string (handles possible detoasting). */
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/* Note we rely on being able to modify rawname below. */
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rawname = DatumGetCString(DirectFunctionCall1(textout,
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PointerGetDatum(textval)));
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rawname = text_to_cstring(textval);
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if (!SplitIdentifierString(rawname, '.', &namelist))
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ereport(ERROR,
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@ -2103,7 +2165,7 @@ byteacmp(PG_FUNCTION_ARGS)
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* appendStringInfoText
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*
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* Append a text to str.
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* Like appendStringInfoString(str, PG_TEXT_GET_STR(s)) but faster.
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* Like appendStringInfoString(str, text_to_cstring(t)) but faster.
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*/
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static void
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appendStringInfoText(StringInfo str, const text *t)
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@ -2191,7 +2253,7 @@ replace_text(PG_FUNCTION_ARGS)
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text_position_cleanup(&state);
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ret_text = PG_STR_GET_TEXT(str.data);
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ret_text = cstring_to_text_with_len(str.data, str.len);
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pfree(str.data);
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PG_RETURN_TEXT_P(ret_text);
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@ -2458,7 +2520,7 @@ replace_text_regexp(text *src_text, void *regexp,
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appendBinaryStringInfo(&buf, start_ptr, chunk_len);
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}
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ret_text = PG_STR_GET_TEXT(buf.data);
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ret_text = cstring_to_text_with_len(buf.data, buf.len);
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pfree(buf.data);
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pfree(data);
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@ -2503,7 +2565,7 @@ split_text(PG_FUNCTION_ARGS)
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if (inputstring_len < 1)
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{
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text_position_cleanup(&state);
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PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
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PG_RETURN_TEXT_P(cstring_to_text(""));
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}
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/* empty field separator */
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@ -2514,7 +2576,7 @@ split_text(PG_FUNCTION_ARGS)
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if (fldnum == 1)
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PG_RETURN_TEXT_P(inputstring);
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else
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PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
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PG_RETURN_TEXT_P(cstring_to_text(""));
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}
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/* identify bounds of first field */
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@ -2529,7 +2591,7 @@ split_text(PG_FUNCTION_ARGS)
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if (fldnum == 1)
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PG_RETURN_TEXT_P(inputstring);
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else
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PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
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PG_RETURN_TEXT_P(cstring_to_text(""));
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}
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while (end_posn > 0 && --fldnum > 0)
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@ -2551,7 +2613,7 @@ split_text(PG_FUNCTION_ARGS)
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-1,
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true);
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else
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result_text = PG_STR_GET_TEXT("");
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result_text = cstring_to_text("");
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}
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else
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{
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@ -2636,9 +2698,7 @@ text_to_array(PG_FUNCTION_ARGS)
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}
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/* must build a temp text datum to pass to accumArrayResult */
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result_text = (text *) palloc(VARHDRSZ + chunk_len);
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SET_VARSIZE(result_text, VARHDRSZ + chunk_len);
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memcpy(VARDATA(result_text), start_ptr, chunk_len);
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result_text = cstring_to_text_with_len(start_ptr, chunk_len);
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/* stash away this field */
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astate = accumArrayResult(astate,
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@ -2673,7 +2733,7 @@ Datum
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array_to_text(PG_FUNCTION_ARGS)
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{
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ArrayType *v = PG_GETARG_ARRAYTYPE_P(0);
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char *fldsep = PG_TEXTARG_GET_STR(1);
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char *fldsep = text_to_cstring(PG_GETARG_TEXT_PP(1));
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int nitems,
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*dims,
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ndims;
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@ -2695,7 +2755,7 @@ array_to_text(PG_FUNCTION_ARGS)
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/* if there are no elements, return an empty string */
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if (nitems == 0)
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PG_RETURN_TEXT_P(PG_STR_GET_TEXT(""));
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PG_RETURN_TEXT_P(cstring_to_text(""));
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element_type = ARR_ELEMTYPE(v);
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initStringInfo(&buf);
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@ -2773,7 +2833,7 @@ array_to_text(PG_FUNCTION_ARGS)
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}
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}
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PG_RETURN_TEXT_P(PG_STR_GET_TEXT(buf.data));
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PG_RETURN_TEXT_P(cstring_to_text_with_len(buf.data, buf.len));
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}
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#define HEXBASE 16
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@ -2785,7 +2845,6 @@ Datum
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to_hex32(PG_FUNCTION_ARGS)
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{
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uint32 value = (uint32) PG_GETARG_INT32(0);
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text *result_text;
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char *ptr;
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const char *digits = "0123456789abcdef";
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char buf[32]; /* bigger than needed, but reasonable */
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@ -2799,8 +2858,7 @@ to_hex32(PG_FUNCTION_ARGS)
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value /= HEXBASE;
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} while (ptr > buf && value);
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result_text = PG_STR_GET_TEXT(ptr);
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PG_RETURN_TEXT_P(result_text);
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PG_RETURN_TEXT_P(cstring_to_text(ptr));
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}
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/*
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@ -2811,7 +2869,6 @@ Datum
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to_hex64(PG_FUNCTION_ARGS)
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{
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uint64 value = (uint64) PG_GETARG_INT64(0);
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text *result_text;
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char *ptr;
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const char *digits = "0123456789abcdef";
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char buf[32]; /* bigger than needed, but reasonable */
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@ -2825,8 +2882,7 @@ to_hex64(PG_FUNCTION_ARGS)
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value /= HEXBASE;
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} while (ptr > buf && value);
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result_text = PG_STR_GET_TEXT(ptr);
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PG_RETURN_TEXT_P(result_text);
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PG_RETURN_TEXT_P(cstring_to_text(ptr));
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}
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/*
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@ -2842,7 +2898,6 @@ md5_text(PG_FUNCTION_ARGS)
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text *in_text = PG_GETARG_TEXT_PP(0);
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size_t len;
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char hexsum[MD5_HASH_LEN + 1];
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text *result_text;
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/* Calculate the length of the buffer using varlena metadata */
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len = VARSIZE_ANY_EXHDR(in_text);
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@ -2854,8 +2909,7 @@ md5_text(PG_FUNCTION_ARGS)
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errmsg("out of memory")));
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/* convert to text and return it */
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result_text = PG_STR_GET_TEXT(hexsum);
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PG_RETURN_TEXT_P(result_text);
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PG_RETURN_TEXT_P(cstring_to_text(hexsum));
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}
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/*
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@ -2868,7 +2922,6 @@ md5_bytea(PG_FUNCTION_ARGS)
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bytea *in = PG_GETARG_BYTEA_PP(0);
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size_t len;
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char hexsum[MD5_HASH_LEN + 1];
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text *result_text;
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len = VARSIZE_ANY_EXHDR(in);
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if (pg_md5_hash(VARDATA_ANY(in), len, hexsum) == false)
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@ -2876,8 +2929,7 @@ md5_bytea(PG_FUNCTION_ARGS)
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(errcode(ERRCODE_OUT_OF_MEMORY),
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errmsg("out of memory")));
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result_text = PG_STR_GET_TEXT(hexsum);
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PG_RETURN_TEXT_P(result_text);
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PG_RETURN_TEXT_P(cstring_to_text(hexsum));
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}
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/*
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