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authornobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2004-07-01 14:15:38 +0000
committernobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2004-07-01 14:15:38 +0000
commit7800d8ad76bfda9884f5127c576ba08b1fe82583 (patch)
tree60f53b0878437539143899edaaa35a54635b3182 /lib/pstore.rb
parentc7bd86ed15eb4baf2dcb9a7b732891de4619d88a (diff)
* lib/pstore.rb (transaction): safer backup scheme. [ruby-list:39102]
* lib/pstore.rb (commit_new): use FileUtils.copy_stream for Cygwin. [ruby-dev:23157] * lib/pstore.rb (transaction): allow overriding dump and load. [ruby-dev:23567] * lib/pstore.rb (PStore#transaction): get rid of opening in write mode when read only transaction. [ruby-dev:23842] * lib/yaml/store.rb: follow lib/pstore.rb's change. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@6562 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'lib/pstore.rb')
-rw-r--r--lib/pstore.rb98
1 files changed, 63 insertions, 35 deletions
diff --git a/lib/pstore.rb b/lib/pstore.rb
index 9379549..c4c6dd5 100644
--- a/lib/pstore.rb
+++ b/lib/pstore.rb
@@ -12,7 +12,7 @@
# p db["root"]
# end
-require "ftools"
+require "fileutils"
require "digest/md5"
class PStore
@@ -35,7 +35,11 @@ class PStore
def in_transaction
raise PStore::Error, "not in transaction" unless @transaction
end
- private :in_transaction
+ def in_transaction_wr()
+ in_transaction()
+ raise PStore::Error, "in read-only transaction" if @rdonly
+ end
+ private :in_transaction, :in_transaction_wr
def [](name)
in_transaction
@@ -52,11 +56,11 @@ class PStore
self[name]
end
def []=(name, value)
- in_transaction
+ in_transaction_wr()
@table[name] = value
end
def delete(name)
- in_transaction
+ in_transaction_wr()
@table.delete name
end
@@ -86,27 +90,35 @@ class PStore
def transaction(read_only=false)
raise PStore::Error, "nested transaction" if @transaction
begin
+ @rdonly = read_only
+ @abort = false
@transaction = true
value = nil
- backup = @filename+"~"
- begin
- file = File::open(@filename, read_only ? "rb" : "rb+")
- orig = true
- rescue Errno::ENOENT
- raise if read_only
- file = File::open(@filename, "wb+")
+ new_file = @filename + ".new"
+
+ content = nil
+ unless read_only
+ file = File.open(@filename, File::RDWR | File::CREAT)
+ file.flock(File::LOCK_EX)
+ commit_new(file) if FileTest.exist?(new_file)
+ content = file.read()
+ else
+ file = File.open(@filename, File::RDONLY)
+ file.flock(File::LOCK_SH)
+ content = (File.read(new_file) rescue file.read())
end
- file.flock(read_only ? File::LOCK_SH : File::LOCK_EX)
- if read_only
- @table = Marshal::load(file)
- elsif orig and (content = file.read) != ""
- @table = Marshal::load(content)
- size = content.size
- md5 = Digest::MD5.digest(content)
- content = nil # unreference huge data
+
+ if content != ""
+ @table = load(content)
+ if !read_only
+ size = content.size
+ md5 = Digest::MD5.digest(content)
+ end
else
@table = {}
end
+ content = nil # unreference huge data
+
begin
catch(:pstore_abort_transaction) do
value = yield(self)
@@ -116,24 +128,17 @@ class PStore
raise
ensure
if !read_only and !@abort
- file.rewind
- content = Marshal::dump(@table)
+ tmp_file = @filename + ".tmp"
+ content = dump(@table)
if !md5 || size != content.size || md5 != Digest::MD5.digest(content)
- File::copy @filename, backup
- begin
- file.write(content)
- file.truncate(file.pos)
- content = nil # unreference huge data
- rescue
- File::rename backup, @filename if File::exist?(backup)
- raise
- end
- end
- end
- if @abort and !orig
- File.unlink(@filename)
+ File.open(tmp_file, "w") {|t|
+ t.write(content)
+ }
+ File.rename(tmp_file, new_file)
+ commit_new(file)
+ end
+ content = nil # unreference huge data
end
- @abort = false
end
ensure
@table = nil
@@ -142,6 +147,29 @@ class PStore
end
value
end
+
+ def dump(table)
+ Marshal::dump(table)
+ end
+
+ def load(content)
+ Marshal::load(content)
+ end
+
+ def load_file(file)
+ Marshal::load(file)
+ end
+
+ private
+ def commit_new(f)
+ f.truncate(0)
+ f.rewind
+ new_file = @filename + ".new"
+ File.open(new_file) do |nf|
+ FileUtils.copy_stream(nf, f)
+ end
+ File.unlink(new_file)
+ end
end
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