Can I get logs based on content?
Let's say I want to know who introduced the code for a function, I will have to check the logs and their comments (checkin messages). If someone forgot to put in a log message, I will have to check each diff which would take a lot of time.
Could some tool, like FishEye, do it?
Look at svn blame FILE or svn ann FILE. This will give you the file's contents, however with each line preceeded by the revision number and author of who last changed it.
TortoiseSVN and most other SVN GUI Clients have annotation software built in, as well as IDEs.
FishEye is repository browsing application by Atlassian and does it by default when opening the file. I just tried it in the sandbox, you'll see everything is highlighted by default: http://sandbox.fisheye.atlassian.com/browse/antlr/BUILD.txt?r=6087