Implement data inlined with the index file

This patch allows you to optionally inline data bytes with the
revlog index file.  It saves considerable space and checkout
time by reducing the number of inodes, wasted partial blocks and
system calls.

To use the inline data add this to your .hgrc

[revlog]
# inline data only works with revlogng
format=1
# inline is the only valid flag right now.
flags=inline

mercurial/localrepo.py

@@ -43,12 +43,23 b' class localrepository(object):'
 
         v = self.ui.revlogopts
         self.revlogversion = int(v.get('format', 0))
+        flags = 0
         for x in v.get('flags', "").split():
-            self.revlogversion |= revlog.flagstr(x)
+            flags |= revlog.flagstr(x)
+
+        v = self.revlogversion | flags
+        self.manifest = manifest.manifest(self.opener, v)
+        self.changelog = changelog.changelog(self.opener, v)
 
-        self.manifest = manifest.manifest(self.opener, self.revlogversion)
-        self.changelog = changelog.changelog(self.opener, self.revlogversion)
-        self.revlogversion = self.changelog.version
+        # the changelog might not have the inline index flag
+        # on.  If the format of the changelog is the same as found in
+        # .hgrc, apply any flags found in the .hgrc as well.
+        # Otherwise, just version from the changelog
+        v = self.changelog.version
+        if v == self.revlogversion:
+            v |= flags
+        self.revlogversion = v
+
         self.tagscache = None
         self.nodetagscache = None
         self.encodepats = None

mercurial/revlog.py

@@ -20,6 +20,14 b' demandload(globals(), "sha struct zlib")'
 REVLOGV0 = 0
 REVLOGNG = 1
 
+# revlog flags
+REVLOGNGINLINEDATA = (1 << 16)
+
+def flagstr(flag):
+    if flag == "inline":
+        return REVLOGNGINLINEDATA
+    raise RevlogError(_("unknown revlog flag %s" % flag))
+
 def hash(text, p1, p2):
     """generate a hash from the given text and its parent hashes
 
@@ -234,13 +242,19 b' class revlog(object):'
                 self.indexstat = st
                 if len(i) > 0:
                     v = struct.unpack(versionformat, i[:4])[0]
-                    if v != 0:
-                        flags = v & ~0xFFFF
-                        fmt = v & 0xFFFF
-                        if fmt != REVLOGNG or (flags & ~(REVLOGNGINLINEDATA)):
-                            raise RevlogError(
-                             _("unknown version format %d or flags %x on %s") %
-                             (v, flags, self.indexfile))
+        flags = v & ~0xFFFF
+        fmt = v & 0xFFFF
+        if fmt == 0:
+            if flags:
+                raise RevlogError(_("index %s invalid flags %x for format v0" %
+                                   (self.indexfile, flags)))
+        elif fmt == REVLOGNG:
+            if flags & ~REVLOGNGINLINEDATA:
+                raise RevlogError(_("index %s invalid flags %x for revlogng" %
+                                   (self.indexfile, flags)))
+        else:
+            raise RevlogError(_("index %s invalid format %d" %
+                               (self.indexfile, fmt)))
         self.version = v
         if v == 0:
             self.indexformat = indexformatv0
@@ -248,13 +262,17 b' class revlog(object):'
             self.indexformat = indexformatng
 
         if i:
-            if st and st.st_size > 10000:
+            if not self.inlinedata() and st and st.st_size > 10000:
                 # big index, let's parse it on demand
                 parser = lazyparser(i, self, self.indexformat)
                 self.index = lazyindex(parser)
                 self.nodemap = lazymap(parser)
             else:
                 self.parseindex(i)
+            if self.inlinedata():
+                # we've already got the entire data file read in, save it
+                # in the chunk data
+                self.chunkcache = (0, i)
             if self.version != 0:
                 e = list(self.index[0])
                 type = self.ngtype(e[0])
@@ -270,6 +288,7 b' class revlog(object):'
         l = len(data)
         self.index = []
         self.nodemap =  {nullid: -1}
+        inline = self.inlinedata()
         off = 0
         n = 0
         while off < l:
@@ -278,6 +297,8 b' class revlog(object):'
             self.nodemap[e[-1]] = n
             n += 1
             off += s
+            if inline:
+                off += e[1]
 
     def ngoffset(self, q):
         if q & 0xFFFF:
@@ -297,6 +318,7 b' class revlog(object):'
             p = self.index.p
             p.load()
 
+    def inlinedata(self): return self.version & REVLOGNGINLINEDATA
     def tip(self): return self.node(len(self.index) - 1)
     def count(self): return len(self.index)
     def node(self, rev):
@@ -568,11 +590,17 b' class revlog(object):'
 
     def chunk(self, rev, df=None, cachelen=4096):
         start, length = self.start(rev), self.length(rev)
+        inline = self.inlinedata()
+        if inline:
+            start += (rev + 1) * struct.calcsize(self.indexformat)
         end = start + length
         def loadcache(df):
             cache_length = max(cachelen, length) # 4k
             if not df:
-                df = self.opener(self.datafile)
+                if inline:
+                    df = self.opener(self.indexfile)
+                else:
+                    df = self.opener(self.datafile)
             df.seek(start)
             self.chunkcache = (start, df.read(cache_length))
 
@@ -620,7 +648,11 b' class revlog(object):'
         rev = self.rev(node)
         base = self.base(rev)
 
-        df = self.opener(self.datafile)
+        if self.inlinedata():
+            # we probably have the whole chunk cached
+            df = None
+        else:
+            df = self.opener(self.datafile)
 
         # do we have useful data cached?
         if self.cache and self.cache[1] >= base and self.cache[1] < rev:
@@ -643,6 +675,40 b' class revlog(object):'
         self.cache = (node, rev, text)
         return text
 
+    def checkinlinesize(self, fp, tr):
+        if not self.inlinedata():
+            return
+        size = fp.tell()
+        if size < 131072:
+            return
+        tr.add(self.datafile, 0)
+        df = self.opener(self.datafile, 'w')
+        calc = struct.calcsize(self.indexformat)
+        for r in xrange(self.count()):
+            start = self.start(r) + (r + 1) * calc
+            length = self.length(r)
+            fp.seek(start)
+            d = fp.read(length)
+            df.write(d)
+        fp.close()
+        df.close()
+        fp = self.opener(self.indexfile, 'w', atomic=True)
+        self.version &= ~(REVLOGNGINLINEDATA)
+        if self.count():
+            x = self.index[0]
+            e = struct.pack(self.indexformat, *x)[4:]
+            l = struct.pack(versionformat, self.version)
+            fp.write(l)
+            fp.write(e)
+
+        for i in xrange(1, self.count()):
+            x = self.index[i]
+            e = struct.pack(self.indexformat, *x)
+            fp.write(e)
+
+        fp.close()
+        self.chunkcache = None
+
     def addrevision(self, text, transaction, link, p1=None, p2=None, d=None):
         """add a revision to the log
 
@@ -698,13 +764,17 b' class revlog(object):'
         self.nodemap[node] = n
         entry = struct.pack(self.indexformat, *e)
 
-        transaction.add(self.datafile, offset)
-        transaction.add(self.indexfile, n * len(entry))
-        f = self.opener(self.datafile, "a")
-        if data[0]:
-            f.write(data[0])
-        f.write(data[1])
-        f = self.opener(self.indexfile, "a")
+        if not self.inlinedata():
+            transaction.add(self.datafile, offset)
+            transaction.add(self.indexfile, n * len(entry))
+            f = self.opener(self.datafile, "a")
+            if data[0]:
+                f.write(data[0])
+            f.write(data[1])
+            f = self.opener(self.indexfile, "a")
+        else:
+            f = self.opener(self.indexfile, "a+")
+            transaction.add(self.indexfile, f.tell())
 
         if len(self.index) == 1 and self.version != 0:
             l = struct.pack(versionformat, self.version)
@@ -713,6 +783,11 b' class revlog(object):'
 
         f.write(entry)
 
+        if self.inlinedata():
+            f.write(data[0])
+            f.write(data[1])
+            self.checkinlinesize(f, transaction)
+
         self.cache = (node, n, text)
         return node
 
@@ -830,8 +905,11 b' class revlog(object):'
 
         ifh = self.opener(self.indexfile, "a+")
         transaction.add(self.indexfile, ifh.tell())
-        transaction.add(self.datafile, end)
-        dfh = self.opener(self.datafile, "a")
+        if self.inlinedata():
+            dfh = None
+        else:
+            transaction.add(self.datafile, end)
+            dfh = self.opener(self.datafile, "a")
 
         # loop through our set of deltas
         chain = None
@@ -885,8 +963,21 b' class revlog(object):'
                          link, self.rev(p1), self.rev(p2), node)
                 self.index.append(e)
                 self.nodemap[node] = r
-                dfh.write(cdelta)
-                ifh.write(struct.pack(self.indexformat, *e))
+                if self.inlinedata():
+                    ifh.write(struct.pack(self.indexformat, *e))
+                    ifh.write(cdelta)
+                    self.checkinlinesize(ifh, transaction)
+                    if not self.inlinedata():
+                        dfh = self.opener(self.datafile, "a")
+                        ifh = self.opener(self.indexfile, "a")
+                else:
+                    if not dfh:
+                        # addrevision switched from inline to conventional
+                        # reopen the index
+                        dfh = self.opener(self.datafile, "a")
+                        ifh = self.opener(self.indexfile, "a")
+                    dfh.write(cdelta)
+                    ifh.write(struct.pack(self.indexformat, *e))
 
             t, r, chain, prev = r, r + 1, node, node
             base = self.base(t)
@@ -915,9 +1006,12 b' class revlog(object):'
 
         # first truncate the files on disk
         end = self.start(rev)
-        df = self.opener(self.datafile, "a")
-        df.truncate(end)
-        end = rev * struct.calcsize(self.indexformat)
+        if not self.inlinedata():
+            df = self.opener(self.datafile, "a")
+            df.truncate(end)
+            end = rev * struct.calcsize(self.indexformat)
+        else:
+            end += rev * struct.calcsize(self.indexformat)
 
         indexf = self.opener(self.indexfile, "a")
         indexf.truncate(end)
@@ -952,6 +1046,12 b' class revlog(object):'
             s = struct.calcsize(self.indexformat)
             i = actual / s
             di = actual - (i * s)
+            if self.inlinedata():
+                databytes = 0
+                for r in xrange(self.count()):
+                    databytes += self.length(r)
+                dd = 0
+                di = actual - self.count() * s - databytes
         except IOError, inst:
             if inst.errno != errno.ENOENT:
                 raise