Figure 10- 67 Branch
The branch condition R0 comes from the return value of the 2nd objc_msgSend. Search
upwards, we can find R5 in figure 10-60; it’s determining if the iMessage “hasContent” again.
Therefore, branch right and arrive at figure 10-68.
Figure 10- 68 Branch
This is an informative figure. If you look close, you’ll discover that most objc_msgSends are
just refreshing UI, making the last objc_msgSend, i.e. [R4 sendMessage:R2] more eye-catching.
What’s R4 and R2? Look upwards, you’ll see they’re CKTranscriptController and the argument
of [self sendComposition:], respectively. Let’s continue analyzing from [CKTranscriptController