Signature matching

migration/ids_signature.7.cr

@@ -0,0 +1,50 @@
+class IDSignature < MG::Base
+  def up : String
+    <<-SQL
+    ALTER TABLE ids ADD COLUMN signature TEXT;
+    SQL
+  end
+
+  def down : String
+    <<-SQL
+    -- remove signature column from ids
+    ALTER TABLE ids RENAME TO tmp;
+
+    CREATE TABLE ids (
+      path TEXT NOT NULL,
+      id TEXT NOT NULL
+    );
+
+    INSERT INTO ids
+    SELECT path, id
+    FROM tmp;
+
+    DROP TABLE tmp;
+
+    -- recreate the indices
+    CREATE UNIQUE INDEX path_idx ON ids (path);
+    CREATE UNIQUE INDEX id_idx ON ids (id);
+
+    -- recreate the foreign key constraint on thumbnails
+    ALTER TABLE thumbnails RENAME TO tmp;
+
+    CREATE TABLE thumbnails (
+      id TEXT NOT NULL,
+      data BLOB NOT NULL,
+      filename TEXT NOT NULL,
+      mime TEXT NOT NULL,
+      size INTEGER NOT NULL,
+      FOREIGN KEY (id) REFERENCES ids (id)
+        ON UPDATE CASCADE
+        ON DELETE CASCADE
+    );
+
+    INSERT INTO thumbnails
+    SELECT * FROM tmp;
+
+    DROP TABLE tmp;
+
+    CREATE UNIQUE INDEX tn_index ON thumbnails (id);
+    SQL
+  end
+end

migration/relative_path.8.cr

@@ -0,0 +1,31 @@
+class RelativePath < MG::Base
+  def up : String
+    base = Config.current.library_path
+    base = base[...-1] if base.ends_with? "/"
+
+    <<-SQL
+    -- update the path column in ids to relative paths
+    UPDATE ids
+    SET path = REPLACE(path, '#{base}', '');
+
+    -- update the path column in titles to relative paths
+    UPDATE titles
+    SET path = REPLACE(path, '#{base}', '');
+    SQL
+  end
+
+  def down : String
+    base = Config.current.library_path
+    base = base[...-1] if base.ends_with? "/"
+
+    <<-SQL
+    -- update the path column in ids to absolute paths
+    UPDATE ids
+    SET path = '#{base}' || path;
+
+    -- update the path column in titles to absolute paths
+    UPDATE titles
+    SET path = '#{base}' || path;
+    SQL
+  end
+end

src/library/entry.cr

@@ -11,13 +11,14 @@ class Entry
     @title = File.basename @zip_path, File.extname @zip_path
     @encoded_title = URI.encode @title
     @size = (File.size @zip_path).humanize_bytes
-    id = storage.get_id @zip_path, false
+    id = storage.get_entry_id @zip_path, File.signature(@zip_path)
     if id.nil?
       id = random_str
       storage.insert_id({
-        path:     @zip_path,
-        id:       id,
-        is_title: false,
+        path:            @zip_path,
+        id:              id,
+        title_signature: nil,
+        entry_signature: File.signature(@zip_path).to_s,
       })
     end
     @id = id

src/library/library.cr

@@ -42,16 +42,6 @@ class Library
         end
       end
     end
-
-    db_interval = Config.current.db_optimization_interval_hours
-    unless db_interval < 1
-      spawn do
-        loop do
-          Storage.default.optimize
-          sleep db_interval.hours
-        end
-      end
-    end
   end
 
   def titles
@@ -119,6 +109,7 @@ class Library
     storage.close
 
     Logger.debug "Scan completed"
+    Storage.default.optimize
   end
 
   def get_continue_reading_entries(username)

src/library/title.cr

@@ -3,19 +3,21 @@ require "../archive"
 class Title
   getter dir : String, parent_id : String, title_ids : Array(String),
     entries : Array(Entry), title : String, id : String,
-    encoded_title : String, mtime : Time, signature : UInt64 = 0
+    encoded_title : String, mtime : Time, signature : UInt64
 
   @entry_display_name_cache : Hash(String, String)?
 
   def initialize(@dir : String, @parent_id)
     storage = Storage.default
-    id = storage.get_id @dir, true
+    @signature = Dir.signature dir
+    id = storage.get_title_id dir, signature
     if id.nil?
       id = random_str
       storage.insert_id({
-        path:     @dir,
-        id:       id,
-        is_title: true,
+        path:            dir,
+        id:              id,
+        title_signature: signature.to_s,
+        entry_signature: nil,
       })
     end
     @id = id
@@ -25,8 +27,6 @@ class Title
     @entries = [] of Entry
     @mtime = File.info(dir).modification_time
 
-    signatures = [] of UInt64
-
     Dir.entries(dir).each do |fn|
       next if fn.starts_with? "."
       path = File.join dir, fn
@@ -35,18 +35,14 @@ class Title
         next if title.entries.size == 0 && title.titles.size == 0
         Library.default.title_hash[title.id] = title
         @title_ids << title.id
-        signatures << title.signature
         next
       end
       if [".zip", ".cbz", ".rar", ".cbr"].includes? File.extname path
         entry = Entry.new path, self
         @entries << entry if entry.pages > 0 || entry.err_msg
-        signatures << File.size entry.zip_path
       end
     end
 
-    @signature = Digest::CRC32.checksum(signatures.sort.join "").to_u64
-
     mtimes = [@mtime]
     mtimes += @title_ids.map { |e| Library.default.title_hash[e].mtime }
     mtimes += @entries.map { |e| e.mtime }

src/storage.cr

@@ -20,9 +20,11 @@ class Storage
   @path : String
   @db : DB::Database?
 
-  alias IDTuple = NamedTuple(path: String,
+  alias IDTuple = NamedTuple(
+    path: String,
     id: String,
-    is_title: Bool)
+    entry_signature: String?,
+    title_signature: String?)
 
   use_default
 
@@ -230,16 +232,82 @@ class Storage
     end
   end
 
-  def get_id(path, is_title)
+  def get_title_id(path, signature)
     id = nil
+    path = Path.new(path).relative_to(Config.current.library_path).to_s
     MainFiber.run do
       get_db do |db|
-        if is_title
-          id = db.query_one? "select id from titles where path = (?)", path,
-            as: String
-        else
-          id = db.query_one? "select id from ids where path = (?)", path,
-            as: String
+        # First attempt to find the matching title in DB using BOTH path
+        #   and signature
+        id = db.query_one? "select id from titles where path = (?) and " \
+                           "signature = (?)", path, signature.to_s, as: String
+
+        should_update = id.nil?
+        # If it fails, try to match using the path only. This could happen
+        #   for example when a new entry is added to the title
+        id ||= db.query_one? "select id from titles where path = (?)", path,
+          as: String
+
+        # If it still fails, we will have to rely on the signature values.
+        #   This could happen when the user moved or renamed the title, or
+        #   a title containing the title
+        unless id
+          # If there are multiple rows with the same signature (this could
+          #   happen simply by bad luck, or when the user copied a title),
+          #   pick the row that has the most similar path to the give path
+          rows = [] of Tuple(String, String)
+          db.query "select id, path from titles where signature = (?)",
+            signature.to_s do |rs|
+            rs.each do
+              rows << {rs.read(String), rs.read(String)}
+            end
+          end
+          row = rows.max_by?(&.[1].components_similarity(path))
+          id = row[0] if row
+        end
+
+        # At this point, `id` would still be nil if there's no row matching
+        #   either the path or the signature
+
+        # If we did identify a matching title, save the path and signature
+        #   values back to the DB
+        if id && should_update
+          db.exec "update titles set path = (?), signature = (?) " \
+                  "where id = (?)", path, signature.to_s, id
+        end
+      end
+    end
+    id
+  end
+
+  # See the comments in `#get_title_id` to see how this method works.
+  def get_entry_id(path, signature)
+    id = nil
+    path = Path.new(path).relative_to(Config.current.library_path).to_s
+    MainFiber.run do
+      get_db do |db|
+        id = db.query_one? "select id from ids where path = (?) and " \
+                           "signature = (?)", path, signature.to_s, as: String
+
+        should_update = id.nil?
+        id ||= db.query_one? "select id from ids where path = (?)", path,
+          as: String
+
+        unless id
+          rows = [] of Tuple(String, String)
+          db.query "select id, path from ids where signature = (?)",
+            signature.to_s do |rs|
+            rs.each do
+              rows << {rs.read(String), rs.read(String)}
+            end
+          end
+          row = rows.max_by?(&.[1].components_similarity(path))
+          id = row[0] if row
+        end
+
+        if id && should_update
+          db.exec "update ids set path = (?), signature = (?) " \
+                  "where id = (?)", path, signature.to_s, id
         end
       end
     end
@@ -256,11 +324,14 @@ class Storage
         db.transaction do |tran|
           conn = tran.connection
           @@insert_ids.each do |tp|
-            if tp[:is_title]
-              conn.exec "insert into titles values (?, ?, null)", tp[:id],
-                tp[:path]
+            path = Path.new(tp[:path])
+              .relative_to(Config.current.library_path).to_s
+            if tp[:title_signature]
+              conn.exec "insert into titles values (?, ?, ?)", tp[:id],
+                path, tp[:title_signature].to_s
             else
-              conn.exec "insert into ids values (?, ?)", tp[:path], tp[:id]
+              conn.exec "insert into ids values (?, ?, ?)", path, tp[:id],
+                tp[:entry_signature].to_s
             end
           end
         end
@@ -363,7 +434,8 @@ class Storage
         db.query "select path, id from ids" do |rs|
           rs.each do
             path = rs.read String
-            trash_ids << rs.read String unless File.exists? path
+            fullpath = Path.new(path).expand(Config.current.library_path).to_s
+            trash_ids << rs.read String unless File.exists? fullpath
           end
         end
 
@@ -377,7 +449,8 @@ class Storage
         db.query "select path, id from titles" do |rs|
           rs.each do
             path = rs.read String
-            trash_titles << rs.read String unless Dir.exists? path
+            fullpath = Path.new(path).expand(Config.current.library_path).to_s
+            trash_titles << rs.read String unless Dir.exists? fullpath
           end
         end
 

src/util/signature.cr

@@ -0,0 +1,50 @@
+class File
+  abstract struct Info
+    def inode
+      @stat.st_ino
+    end
+  end
+
+  # Returns the signature of the file at filename.
+  # When it is not a supported file, returns 0. Otherwise, calculate the
+  #   signature by combining its inode value, file size and mtime. This
+  #   ensures that moving (unless to another device) and renaming the file
+  #   preserves the signature, while copying or editing the file changes it.
+  def self.signature(filename) : UInt64
+    return 0u64 unless %w(.zip .rar .cbz .cbr).includes? File.extname filename
+    info = File.info filename
+    signatures = [
+      info.inode,
+      File.size(filename),
+      info.modification_time.to_unix,
+    ]
+    Digest::CRC32.checksum(signatures.sort.join).to_u64
+  end
+end
+
+class Dir
+  # Returns the signature of the directory at dirname.
+  # The signature is calculated by combining its mtime and the signatures of
+  #   all directories and files in it. This ensures that moving (unless to
+  #   another device) and renaming the directory preserves the signature,
+  #   while copying or editing its content changes it.
+  def self.signature(dirname) : UInt64
+    signatures = [] of (UInt64 | Int64)
+    signatures << File.info(dirname).modification_time.to_unix
+    self.open dirname do |dir|
+      dir.entries.each do |fn|
+        next if fn.starts_with? "."
+        path = File.join dirname, fn
+        if File.directory? path
+          signatures << Dir.signature path
+        else
+          _sig = File.signature path
+          # Only add its signature value to `signatures` when it is a
+          #   supported file
+          signatures << _sig if _sig > 0
+        end
+      end
+    end
+    Digest::CRC32.checksum(signatures.sort.join).to_u64
+  end
+end

src/util/util.cr

@@ -92,3 +92,18 @@ def sort_titles(titles : Array(Title), opt : SortOptions, username : String)
 
   ary
 end
+
+class String
+  # Returns the similarity (in [0, 1]) of two paths.
+  # For the two paths, separate them into arrays of components, count the
+  #   number of matching components backwards, and divide the count by the
+  #   number of components of the shorter path.
+  def components_similarity(other : String) : Float64
+    s, l = [self, other]
+      .map { |str| Path.new(str).parts }
+      .sort_by &.size
+
+    match = s.reverse.zip(l.reverse).count { |a, b| a == b }
+    match / s.size
+  end
+end