get_page_at_revision is working

Author: singingwolfboy

diff.sql

@@ -38,7 +38,7 @@ begin
         --raise notice 'i = %, j = %', i, j;
         --raise notice 'hunk = %', hunk;
         --raise notice 'context here = %', context;
-        if i = 1 or j = 1 then
+        if i = 1 and j = 1 then
             -- we're done!
             IF in_hunk THEN
                 context_length := array_length(context, 1);

patch.sql

@@ -27,7 +27,7 @@ begin
     hunk_line := hunk[hunk_ptr];
 
     LOOP
-        RAISE notice 'op = %, hp = %, ol = %, hl = %', orig_ptr, hunk_ptr, orig_line, hunk_line;
+        --RAISE notice 'op = %, hp = %, ol = %, hl = %', orig_ptr, hunk_ptr, orig_line, hunk_line;
         IF hunk_line IS NULL THEN
             -- End of the hunk. Wrap up the rest, and leave.
             RETURN result || original[orig_ptr:orig_length];
@@ -76,3 +76,63 @@ begin
 end;
 $$ language plpgsql
 IMMUTABLE;
+
+create or replace function get_page_at_revision(page_id int, revision int)
+--    returns page as $$
+    returns page_latest as $$
+#variable_conflict use_variable
+declare
+    latest page_latest;
+    diff page_diff;
+    hunk page_diff_hunk;
+    content text[];
+    cur_rev int := -1;
+    line_offset int := 0;
+    result page_latest;
+begin
+    IF revision < 1 THEN
+        RAISE 'Revision must be positive (got %)', revision;
+    END IF;
+    SELECT * INTO latest FROM page_latest WHERE id = page_id;
+    IF NOT FOUND THEN
+        RAISE 'Page % not found', id;
+    END IF;
+    IF revision > latest.revision THEN
+        RAISE 'Revision does not exist (requested %, latest is %)', revision,
+            latest.revision;
+    END IF;
+    IF revision = latest.revision THEN
+        result := latest::page_latest;
+        RETURN result;
+    END IF;
+    SELECT * INTO diff FROM page_diff AS pd
+        WHERE pd.page_id = page_id
+        AND pd.revision = revision;
+    IF NOT FOUND THEN
+        RAISE 'Revision % for page % not found', revision, page_id;
+    END IF;
+    content = string_to_array(latest.content, E'\n');
+    FOR hunk IN SELECT * FROM page_diff_hunk AS pdh 
+                WHERE pdh.page_id = page_id
+                AND pdh.revision >= revision
+                ORDER BY pdh.revision desc, pdh.start asc
+    LOOP
+        IF cur_rev != hunk.revision THEN
+            line_offset := 0;
+            cur_rev := hunk.revision;
+        END IF;
+        --raise notice 'start = %, offset = %, rev = %', hunk.start, line_offset, cur_rev;
+        content := apply_hunk(content,
+            string_to_array(hunk.content, E'\n'),
+            hunk.start + line_offset,
+            TRUE);
+        line_offset := line_offset + hunk.lines_added - hunk.lines_deleted;
+    END LOOP;
+    result := (latest.id, latest.title, latest.slug, latest.namespace,
+        array_to_string(content, E'\n'), diff.comment,
+        array_length(content, 1), revision, diff.editor, latest.markup,
+        latest.language, diff.created_on);
+    RETURN result;
+end;
+$$ language plpgsql
+STABLE STRICT;

tables.sql

@@ -17,7 +17,7 @@ CREATE TABLE page_latest (
     content text DEFAULT '',
     comment text DEFAULT '',
     num_lines int NOT NULL,
-    revision int DEFAULT 0 CONSTRAINT "revision must be positive" CHECK (revision >= 0),
+    revision int DEFAULT 1 CONSTRAINT "revision must be positive" CHECK (revision > 0),
     editor int REFERENCES "user"(id),
     markup varchar(64) DEFAULT 'plain',
     language varchar(8) NOT NULL,
@@ -39,7 +39,7 @@ DROP TABLE IF EXISTS page_diff_hunk;
 CREATE TABLE page_diff_hunk (
     page_id int,
     revision int,
-    start int NOT NULL CONSTRAINT "start must be positive" CHECK (start >= 0),
+    start int NOT NULL CONSTRAINT "start must be positive" CHECK (start > 0),
     content text NOT NULL DEFAULT '',
     lines_added int NOT NULL DEFAULT 0,
     lines_deleted int NOT NULL DEFAULT 0,

test.sql

@@ -1,31 +1,50 @@
 truncate page_latest, page_diff, page_diff_hunk;
 INSERT INTO user(id, username, email) VALUES (1, 'foo', 'foo');
 INSERT INTO page_latest(id, title, slug, num_lines, editor, language, content)
-    VALUES (1, 'page', 'page', 15, 1, 'en-us', 
+    VALUES (1, 'page', 'page', 3, 1, 'en-us', 
 'a
 b
+c');
+
+SELECT update_page(1, 'b
 c
+d', 1);
+SELECT update_page(1, 'c
 d
+e', 1);
+SELECT update_page(1, 'd
 e
+f', 1);
+
+
+SELECT update_page(1, 
+'a
+b
+c
+d
+carrot
 f
 g
 h
 i
-j
+u
 k
 l
 m
-n
+stick
 o
-p');
+p', 1);
 
+INSERT INTO page_latest(id, title, slug, num_lines, editor, language, content)
+    VALUES (2, 'short', 'short', 3, 1, 'en-us', E'a\nb\nc');
+SELECT update_page(2, E'a\nx\nc\nd', 1);
 
-SELECT update_page(1, 
-'a
+
+select apply_hunk('a
 b
 c
 d
-carrot
+e
 f
 g
 h
@@ -34,10 +53,23 @@ j
 k
 l
 m
-stick
+n
 o
-p', 1);
-
-INSERT INTO page_latest(id, title, slug, num_lines, editor, language, content)
-    VALUES (2, 'short', 'short', 3, 1, 'en-us', E'a\nb\nc');
-SELECT update_page(2, E'a\nx\nc\nd', 1);
+p', ' b
+ c
+ d
++carrot
+-e
+ f
+ g
+ h
+ i
++u
+-j
+ k
+ l
+ m
++stick
+-n
+ o
+ p', 2);