1

     2

DROP TABLE IF EXISTS file_tree;

     3

DROP TABLE IF EXISTS inodes;

     4

DROP SEQUENCE IF EXISTS ino_seq;

     5

     6

CREATE SEQUENCE ino_seq START 64;

     7

     8

-- inodes

     9

CREATE TABLE inodes (

    10

    ino int4 primary key DEFAULT nextval('ino_seq'::regclass), 

    11

    type char(3) NOT NULL, 

    12

    mode int2 NOT NULL, 

    13

    data oid,

    14

    link_path varchar(512),

    15

    16

    -- sanity checks

    17

    CONSTRAINT inodes_valid_reg CHECK (data IS NULL OR type = 'REG'),

    18

    CONSTRAINT inodes_valid_lnk CHECK (link_path IS NULL OR type = 'LNK')

    19

);

    20

    21

-- filesystem layout

    22

CREATE TABLE file_tree (

    23

    "offset" serial4 primary key, 

    24

    name varchar(256), 

    25

    ino int4 references inodes(ino) NOT NULL,

    26

    ino_dir int4 references inodes(ino),

    27

    parent int4,

    28

    29

    -- structure

    30

    CONSTRAINT file_tree_uniq_direntry UNIQUE (parent, name),

    31

    CONSTRAINT file_tree_uniq_dir_ino UNIQUE (ino_dir),

    32

    CONSTRAINT file_tree_exist_parent FOREIGN KEY (parent) REFERENCES file_tree(ino_dir),

    33

    34

    -- sanity checks

    35

    CONSTRAINT file_tree_valid_root CHECK ((parent IS NULL AND name IS NULL AND ino = 1) OR (name IS NOT NULL and parent IS NOT NULL AND ino != 1)),

    36

    CONSTRAINT file_tree_valid_dir CHECK (ino_dir IS NULL OR ino_dir = ino)

    37

);

    38

    39

INSERT INTO inodes (ino, type, mode, data) VALUES 

    40

    (1, 'DIR', 365, NULL),

    41

    (2, 'REG', 292, lo_create(0));

    42

    43

INSERT INTO file_tree (name, parent, ino, ino_dir) VALUES 

    44

    (NULL,  NULL,   1,  1       ),

    45

    ('foo', 1,      2,  NULL    );

    46

    47

-- not sure how these work, I guess statements in functions aren't their own transactions

    48

CREATE OR REPLACE FUNCTION lo_pread_oid (IN obj oid, IN len int4, IN "off" int4) RETURNS bytea LANGUAGE SQL STRICT AS 'select lo_open($1, 393216); select lo_lseek(0, $3, 0); select loread(0, $2);';

    49

CREATE OR REPLACE FUNCTION lo_pwrite_oid (IN obj oid, IN buf bytea, IN "off" int4) RETURNS int4 LANGUAGE SQL STRICT AS 'select lo_open($1, 393216); select lo_lseek(0, $3, 0); select lowrite(0, $2);';

    50

    51

CREATE OR REPLACE FUNCTION lo_otruncate (IN obj oid, IN len int4) RETURNS oid LANGUAGE SQL STRICT AS 'select lo_truncate(lo_open($1, 393216), $2); select $1;';

    52

CREATE OR REPLACE FUNCTION lo_size (oid) RETURNS int4 LANGUAGE SQL STABLE RETURNS NULL ON NULL INPUT AS 'select lo_lseek(lo_open($1, 262144), 0, 2);';

    53

CREATE OR REPLACE FUNCTION dbfs_size (type char, oid, link varchar) RETURNS int4 LANGUAGE SQL STABLE AS $$

    54

    SELECT CASE $1 

    55

        WHEN 'LNK' THEN char_length($3) 

    56

        WHEN 'REG' THEN lo_size($2) 

    57

        ELSE 0 

    58

    END;

    59

$$;

    60

    61

CREATE OR REPLACE FUNCTION dbfs_link (

    62

    IN ino int4, IN new_parent int4, IN new_name varchar, 

    63

    OUT ino int4, OUT type char(3), OUT mode int2, OUT size int4, OUT nlink int8

    64

) LANGUAGE SQL VOLATILE AS $$

    65

    INSERT INTO file_tree (name, ino, parent) VALUES ($3, $1, $2);

    66

    SELECT ino, type, mode, dbfs_size(type, data, link_path) AS size, (SELECT COUNT(*) FROM inodes i LEFT JOIN file_tree ft ON (i.ino = ft.ino) WHERE i.ino = inodes.ino) AS nlink

    67

     FROM inodes WHERE ino = $1;

    68

$$;