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Diffstat (limited to 'src/common/relpath.c')
| -rw-r--r-- | src/common/relpath.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/common/relpath.c b/src/common/relpath.c new file mode 100644 index 0000000..636c96e --- /dev/null +++ b/src/common/relpath.c @@ -0,0 +1,210 @@ +/*------------------------------------------------------------------------- + * relpath.c + * Shared frontend/backend code to compute pathnames of relation files + * + * This module also contains some logic associated with fork names. + * + * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/common/relpath.c + * + *------------------------------------------------------------------------- + */ +#ifndef FRONTEND +#include "postgres.h" +#else +#include "postgres_fe.h" +#endif + +#include "catalog/pg_tablespace_d.h" +#include "common/relpath.h" +#include "storage/backendid.h" + + +/* + * Lookup table of fork name by fork number. + * + * If you add a new entry, remember to update the errhint in + * forkname_to_number() below, and update the SGML documentation for + * pg_relation_size(). + */ +const char *const forkNames[] = { + "main", /* MAIN_FORKNUM */ + "fsm", /* FSM_FORKNUM */ + "vm", /* VISIBILITYMAP_FORKNUM */ + "init" /* INIT_FORKNUM */ +}; + +StaticAssertDecl(lengthof(forkNames) == (MAX_FORKNUM + 1), + "array length mismatch"); + +/* + * forkname_to_number - look up fork number by name + * + * In backend, we throw an error for no match; in frontend, we just + * return InvalidForkNumber. + */ +ForkNumber +forkname_to_number(const char *forkName) +{ + ForkNumber forkNum; + + for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++) + if (strcmp(forkNames[forkNum], forkName) == 0) + return forkNum; + +#ifndef FRONTEND + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("invalid fork name"), + errhint("Valid fork names are \"main\", \"fsm\", " + "\"vm\", and \"init\"."))); +#endif + + return InvalidForkNumber; +} + +/* + * forkname_chars + * We use this to figure out whether a filename could be a relation + * fork (as opposed to an oddly named stray file that somehow ended + * up in the database directory). If the passed string begins with + * a fork name (other than the main fork name), we return its length, + * and set *fork (if not NULL) to the fork number. If not, we return 0. + * + * Note that the present coding assumes that there are no fork names which + * are prefixes of other fork names. + */ +int +forkname_chars(const char *str, ForkNumber *fork) +{ + ForkNumber forkNum; + + for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++) + { + int len = strlen(forkNames[forkNum]); + + if (strncmp(forkNames[forkNum], str, len) == 0) + { + if (fork) + *fork = forkNum; + return len; + } + } + if (fork) + *fork = InvalidForkNumber; + return 0; +} + + +/* + * GetDatabasePath - construct path to a database directory + * + * Result is a palloc'd string. + * + * XXX this must agree with GetRelationPath()! + */ +char * +GetDatabasePath(Oid dbNode, Oid spcNode) +{ + if (spcNode == GLOBALTABLESPACE_OID) + { + /* Shared system relations live in {datadir}/global */ + Assert(dbNode == 0); + return pstrdup("global"); + } + else if (spcNode == DEFAULTTABLESPACE_OID) + { + /* The default tablespace is {datadir}/base */ + return psprintf("base/%u", dbNode); + } + else + { + /* All other tablespaces are accessed via symlinks */ + return psprintf("pg_tblspc/%u/%s/%u", + spcNode, TABLESPACE_VERSION_DIRECTORY, dbNode); + } +} + +/* + * GetRelationPath - construct path to a relation's file + * + * Result is a palloc'd string. + * + * Note: ideally, backendId would be declared as type BackendId, but relpath.h + * would have to include a backend-only header to do that; doesn't seem worth + * the trouble considering BackendId is just int anyway. + */ +char * +GetRelationPath(Oid dbNode, Oid spcNode, Oid relNode, + int backendId, ForkNumber forkNumber) +{ + char *path; + + if (spcNode == GLOBALTABLESPACE_OID) + { + /* Shared system relations live in {datadir}/global */ + Assert(dbNode == 0); + Assert(backendId == InvalidBackendId); + if (forkNumber != MAIN_FORKNUM) + path = psprintf("global/%u_%s", + relNode, forkNames[forkNumber]); + else + path = psprintf("global/%u", relNode); + } + else if (spcNode == DEFAULTTABLESPACE_OID) + { + /* The default tablespace is {datadir}/base */ + if (backendId == InvalidBackendId) + { + if (forkNumber != MAIN_FORKNUM) + path = psprintf("base/%u/%u_%s", + dbNode, relNode, + forkNames[forkNumber]); + else + path = psprintf("base/%u/%u", + dbNode, relNode); + } + else + { + if (forkNumber != MAIN_FORKNUM) + path = psprintf("base/%u/t%d_%u_%s", + dbNode, backendId, relNode, + forkNames[forkNumber]); + else + path = psprintf("base/%u/t%d_%u", + dbNode, backendId, relNode); + } + } + else + { + /* All other tablespaces are accessed via symlinks */ + if (backendId == InvalidBackendId) + { + if (forkNumber != MAIN_FORKNUM) + path = psprintf("pg_tblspc/%u/%s/%u/%u_%s", + spcNode, TABLESPACE_VERSION_DIRECTORY, + dbNode, relNode, + forkNames[forkNumber]); + else + path = psprintf("pg_tblspc/%u/%s/%u/%u", + spcNode, TABLESPACE_VERSION_DIRECTORY, + dbNode, relNode); + } + else + { + if (forkNumber != MAIN_FORKNUM) + path = psprintf("pg_tblspc/%u/%s/%u/t%d_%u_%s", + spcNode, TABLESPACE_VERSION_DIRECTORY, + dbNode, backendId, relNode, + forkNames[forkNumber]); + else + path = psprintf("pg_tblspc/%u/%s/%u/t%d_%u", + spcNode, TABLESPACE_VERSION_DIRECTORY, + dbNode, backendId, relNode); + } + } + return path; +} |